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README.md
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1
2 C and C++ XML Data Bindings {#mainpage}
3 ===========================
4
5 [TOC]
6
7 Introduction {#intro}
8 ============
9
10 This article presents a detailed overview of the gSOAP XML data bindings for C
11 and C++. The XML data bindings for C and C++ are extensively used with gSOAP
12 Web services to serialize C and C++ data in XML as part of the SOAP/XML Web
13 services payloads. Also REST XML with gSOAP relies on XML serialization of C
14 and C++ data via XML data bindings.
15
16 The major advantage of XML data bindings is that your application data is
17 always **type safe** in C and C++ by binding XML schema types to C/C++ types.
18 So integers in XML are bound to C integers, strings in XML are bound to C or
19 C++ strings, complex types in XML are bound to C structs or C++ classes, and so
20 on. The structured data you create and accept will fit the data model and is
21 **static type safe**. In other words, by leveraging strong typing in C/C++,
22 your XML data meets **XML schema validation requirements** and satisfies **XML
23 interoperability requirements**.
24
25 In fact, gSOAP data bindings are more powerful than simply representing C/C++
26 data in XML. The gSOAP tools implement true and tested **structure-preserving
27 serialization** of C/C++ data in XML, including the serialization of cyclic
28 graph structures with id-ref XML attributes. The gSOAP tools also generate
29 routines for deep copying and deep deletion of C/C++ data structures to
30 simplify memory management. In addition, C/C++ structures are deserialized
31 into managed memory, managed by the gSOAP `soap` context.
32
33 At the end of this article two examples are given to illustrate the application
34 of XML data bindings. The first simple example `address.cpp` shows how to use
35 wsdl2h to bind an XML schema to C++. The C++ application reads and writes an
36 XML file into and from a C++ "address book" data structure as a simple example.
37 The C++ data structure is an STL vector of address objects. The second example
38 `graph.cpp` shows how C++ data can be accurately serialized as a tree, digraph,
39 and cyclic graph in XML. The digraph and cyclic graph serialization rules
40 implement SOAP 1.1/1.2 multi-ref encoding with id-ref attributes to link
41 elements through IDREF XML references, creating a an XML graph with pointers to
42 XML nodes that preserves the structural integrity of the serialized C++ data.
43
44 These examples demonstrate XML data bindings only for relatively simple data
45 structures and types. The gSOAP tools support more than just these type of
46 structures to serialize in XML. There are practically no limits to the
47 serialization of C and C++ data types in XML.
48
49 Also the support for XML schema (XSD) components is unlimited. The wsdl2h tool
50 maps schemas to C and C++ using built-in intuitive mapping rules, while
51 allowing the mappings to be customized using a `typemap.dat` file with mapping
52 instructions for wsdl2h.
53
54 The information in this article is applicable to gSOAP 2.8.26 and later
55 versions that support C++11 features. However, C++11 is not required. The
56 material and the examples in this article use plain C and C++, until the point
57 where we introduce C++11 smart pointers and scoped enumerations. While most of
58 the examples in this article are given in C++, the concepts also apply to C
59 with the exception of containers, smart pointers, classes and their methods.
60 None of these exceptions limit the use of the gSOAP tools for C in any way.
61
62 The data binding concepts described in this article were first envisioned in
63 1999 by Prof. Robert van Engelen at the Florida State University. An
64 implementation was created in 2000, named "stub/skeleton compiler". The first
65 articles on its successor version "gSOAP" appeared in 2002. The principle of
66 mapping XSD components to C/C++ types and vice versa is now widely adopted in
67 systems and programming languages, including Java web services and by C# WCF.
68
69 We continue to be committed to our goal to empower C/C++ developers with
70 powerful autocoding tools for XML. Our commitment started in the very early
71 days of SOAP by actively participating in
72 [SOAP interoperability testing](http://www.whitemesa.com/interop.htm),
73 participating in the development and testing of the
74 [W3C XML Schema Patterns for Databinding Interoperability](http://www.w3.org/2002/ws/databinding),
75 and continues by contributing to the development of
76 [OASIS open standards](https://www.oasis-open.org) in partnership with leading
77 IT companies in the world.
78
79 🔝 [Back to table of contents](#)
80
81 Mapping WSDL and XML schemas to C/C++ {#tocpp}
82 =====================================
83
84 To convert WSDL and XML schemas (XSD files) to code, we use the wsdl2h command
85 on the command line (or command prompt), after opening a terminal. The wsdl2h
86 command generates the data binding interface code that is saved to a special
87 gSOAP header file with extension `.h` that contains the WSDL service
88 declarations and the data binding interface declarations in a familiar C/C++
89 format:
90
91 wsdl2h [options] -o file.h ... XSD and WSDL files ...
92
93 This command converts WSDL and XSD files to C++ (or pure C with wsdl2h option
94 `-c`) and saves the data binding interface to a gSOAP header file `file.h` that
95 uses familiar C/C++ syntax extended with `//gsoap` [directives](#directives)
96 and annotations. Notational conventions are used in the data binding interface
97 to declare serializable C/C++ types and functions for Web service operations.
98
99 The WSDL 1.1/2.0, SOAP 1.1/1.2, and XSD 1.0/1.1 standards are supported by the
100 gSOAP tools. In addition, the most popular WS specifications are also
101 supported, including WS-Addressing, WS-ReliableMessaging, WS-Discovery,
102 WS-Security, WS-Policy, WS-SecurityPolicy, and WS-SecureConversation.
103
104 This article focusses mainly on XML data bindings. XML data bindings for C/C++
105 bind XML schema types to C/C++ types. So integers in XML are bound to C
106 integers, strings in XML are bound to C or C++ strings, complex types in XML
107 are bound to C structs or C++ classes, and so on.
108
109 A data binding is dual, meaning supporting a two way direction for development.
110 Either you start with WSDLs and/or XML schemas that are mapped to equivalent
111 C/C++ types, or you start with C/C++ types that are mapped to XSD types.
112 Either way, the end result is that you can serialize C/C++ types in XML such
113 that your XML is an instance of XML schema(s) and is validated against these
114 schema(s).
115
116 This covers all of the following standard XSD components with their optional
117 attributes and properties:
118
119 XSD component | attributes and properties
120 -------------- | -------------------------
121 schema | targetNamespace, version, elementFormDefault, attributeFormDefault, defaultAttributes
122 attribute | name, ref, type, use, default, fixed, form, targetNamespace, wsdl:arrayType
123 element | name, ref, type, default, fixed, form, nillable, abstract, substitutionGroup, minOccurs, maxOccurs, targetNamespace
124 simpleType | name
125 complexType | name, abstract, mixed, defaultAttributesApply
126 all | *n/a*
127 choice | minOccurs, maxOccurs
128 sequence | minOccurs, maxOccurs
129 group | name, ref, minOccurs, maxOccurs
130 attributeGroup | name, ref
131 any | minOccurs, maxOccurs
132 anyAttribute | *n/a*
133
134 And also the following standard XSD directives are covered:
135
136 directive | description
137 ---------- | -----------
138 import | Imports a schema into the importing schema for referencing
139 include | Include schema component definitions into a schema
140 override | Override by replacing schema component definitions
141 redefine | Extend or restrict schema component definitions
142 annotation | Annotates a component
143
144 The XSD facets and their mappings to C/C++ are:
145
146 XSD facet | maps to
147 -------------- | -------
148 enumeration | `enum`
149 simpleContent | class/struct wrapper with `__item` member
150 complexContent | class/struct
151 list | `enum*` bitmask (`enum*` enumerates up to 64 bit masks)
152 extension | class/struct inheritance/extension
153 restriction | `typedef` and class/struct inheritance/redeclaration
154 length | `typedef` with restricted content length annotation
155 minLength | `typedef` with restricted content length annotation
156 maxLength | `typedef` with restricted content length annotation
157 minInclusive | `typedef` with numerical value range restriction annotation
158 maxInclusive | `typedef` with numerical value range restriction annotation
159 minExclusive | `typedef` with numerical value range restriction annotation
160 maxExclusive | `typedef` with numerical value range restriction annotation
161 precision | `typedef` with pattern annotation (pattern used for output, but input is not validated)
162 scale | `typedef` with pattern annotation (pattern used for output, but input is not validated)
163 totalDigits | `typedef` with pattern annotation (pattern used for output, but input is not validated)
164 fractionDigits | `typedef` with pattern annotation (pattern used for output, but input is not validated)
165 pattern | `typedef` with pattern annotation (define `soap::fsvalidate` callback to validate patterns)
166 union | string with union of value
167
168 All primitive XSD types are supported, including but not limited to the
169 following XSD types:
170
171 XSD type | maps to
172 ---------------- | -------
173 any/anyType | `_XML` string with literal XML content (or enable DOM with wsdl2h option `-d`)
174 anyURI | string (i.e. `char*`, `wchar_t*`, `std::string`, `std::wstring`)
175 string | string (i.e. `char*`, `wchar_t*`, `std::string`, `std::wstring`)
176 boolean | `bool` (C++) or `enum xsd__boolean` (C)
177 byte | `char` (i.e. `int8_t`)
178 short | `short` (i.e. `int16_t`)
179 int | `int` (i.e. `int32_t`)
180 long | `LONG64` (i.e. `long long` and `int64_t`)
181 unsignedByte | `unsigned char` (i.e. `uint8_t`)
182 unsignedShort | `unsigned short` (i.e. `uint16_t`)
183 unsignedInt | `unsigned int` (i.e. `uint32_t`)
184 unsignedLong | `ULONG64` (i.e. `unsigned long long` and `uint64_t`)
185 float | `float`
186 double | `double`
187 integer | string or `#import "custom/int128.h"` to use 128 bit `xsd__integer`
188 decimal | string or `#import "custom/long_double.h"` to use `long double`
189 precisionDecimal | string
190 duration | string or `#import "custom/duration.h"` to use 64 bit `xsd__duration`
191 dateTime | `time_t` or `#import "custom/struct_tm.h"` to use `struct tm` for `xsd__dateTime`
192 time | string or `#import "custom/long_time.h"` to use 64 bit `xsd__time`
193 date | string or `#import "custom/struct_tm_date.h"` to use `struct tm` for `xsd__date`
194 hexBinary | special class/struct `xsd__hexBinary`
195 base64Bianry | special class/struct `xsd__base64Binary`
196 QName | `_QName` string (URI normalization rules are applied)
197
198 All other primitive XSD types not listed above are mapped to strings, by
199 wsdl2h generating a typedef to string for these types. For example,
200 `xsd:token` is bound to a C++ or C string:
201
202 ```cpp
203 typedef std::string xsd__token; // C++
204 typedef char *xsd__token; // C (wsdl2h option -c)
205 ```
206
207 This associates a compatible value space to the type with the appropriate XSD
208 type name used by the soapcpp2-generated serializers.
209
210 It is possible to remap types by adding the appropriate mapping rules to
211 `typemap.dat` as we will explain in more detail in the next section.
212
213 Imported custom serializers are intended to extend the C/C++ type bindings when
214 the default binding to string is not satisfactory to your taste and if the
215 target platform supports these C/C++ types. To add custom serializers to
216 `typemap.dat` for wsdl2h, see [adding custom serializers](#custom) below.
217
218 🔝 [Back to table of contents](#)
219
220 Using typemap.dat to customize data bindings {#typemap}
221 ============================================
222
223 Use a `typemap.dat` file to redefine namespace prefixes and to customize type
224 bindings for the the generated header files produced by the wsdl2h tool. The
225 `typemap.dat` is the default file processed by wsdl2h. Use wsdl2h option `-t`
226 to specify a different file.
227
228 Declarations in `typemap.dat` can be broken up over multiple lines by
229 continuing on the next line by ending each line to be continued with a
230 backslash `\`. The limit is 4095 characters per line, whether the line is
231 broken up or not.
232
233 🔝 [Back to table of contents](#)
234
235 XML namespace bindings {#typemap1}
236 ----------------------
237
238 The wsdl2h tool generates C/C++ type declarations that use `ns1`, `ns2`, etc.
239 as schema-binding URI prefixes. These default prefixes are generated somewhat
240 arbitrarily for each schema targetNamespace URI, meaning that their ordering
241 may change depending on the WSDL and XSD order of processing with wsdl2h.
242
243 Therefore, it is **strongly recommended** to declare your own prefix for each
244 schema URI in `typemap.dat` to reduce maintaince effort of your code. This
245 is more robust when anticipating possible changes of the schema(s) and/or the
246 binding URI(s) and/or the tooling algorithms.
247
248 The first and foremost important thing to do is to define prefix-URI bindings
249 for our C/C++ code by adding the following line(s) to our `typemap.dat` or make
250 a copy of this file and add the line(s) that bind our choice of prefix name to
251 each URI:
252
253 prefix = "URI"
254
255 For example, to use `g` as a prefix for the "urn:graph" XML namespace:
256
257 g = "urn:graph"
258
259 This produces `g__name` C/C++ type names that are bound to the "urn:graph"
260 schema by association of `g` to the generated C/C++ types.
261
262 This means that `<g:name xmlns:g="urn:graph">` is parsed as an instance of a
263 `g__name` C/C++ type. Also `<x:name xmlns:x="urn:graph">` parses as an
264 instance of `g__name`, because the prefix `x` has the same URI value
265 `urn:graph`. Prefixes in XML have local scopes (like variables in a block).
266
267 The first run of wsdl2h will reveal the XML namespace URIs, so you do not need
268 to search WSDLs and XSD files for all of the target namespaces. Just copy them
269 from the generated header file after the first run into `typemap.dat` for
270 editing.
271
272 @note Only define a namespace prefix once in `typemap.dat`. That is, do not
273 use the same prefix for multiple XML namespace URIs. This is to avoid
274 namespace conflicts that may cause failed builds and failures in XML parsing
275 and XML schema validation.
276
277 🔝 [Back to table of contents](#)
278
279 XSD type bindings {#typemap2}
280 -----------------
281
282 Custom C/C++ type bindings can be declared in `typemap.dat` to associate C/C++
283 types with specific schema types. These type bindings have four parts:
284
285 prefix__type = declaration | use | ptruse
286
287 where
288
289 - `prefix__type` is the schema type to be customized (the `prefix__type` name
290 uses the common double underscore naming convention);
291 - `declaration` declares the C/C++ type in the wsdl2h-generated header file.
292 This part can be empty if no explicit declaration is needed;
293 - `use` is an optional part that specifies how the C/C++ type is used in the
294 code. When omitted, it is the same as `prefix__type`;
295 - `ptruse` is an optional part that specifies how the type is used as a pointer
296 type. By default it is the `use` type name with a `*` or C++11
297 `std::shared_ptr<>` when enabled (see further below). If `use` is already a
298 pointer type by the presence of a `*` in the `use` part, then the default
299 `ptruse` type is the same as the `use` type (that is, no double pointer `**`
300 will be created in this case).
301
302 For example, to map `xsd:duration` to a `long long` (`LONG64`) type that holds
303 millisecond duration values, we can use the custom serializer declared in
304 `custom/duration.h` by adding the following line to `typemap.dat`:
305
306 xsd__duration = #import "custom/duration.h"
307
308 Here, we omitted the second and third parts, because `xsd__duration` is the
309 name that wsdl2h uses for this type in our generated code so we should leave
310 the `use` part unspecified. The third part is omitted to let wsdl2h use
311 `xsd__duration *` for pointers or `std::shared_ptr<xsd__duration>` if smart
312 pointers are enabled.
313
314 To map `xsd:string` to `wchar_t*` wide strings:
315
316 xsd__string = | wchar_t* | wchar_t*
317
318 Note that the first part is empty, because `wchar_t` is a C type and does not
319 need to be declared. A `ptruse` part is also defined in this example, but does
320 not need to be because the `use` part `wchar_t*` is already a pointer.
321
322 When the auto-generated declaration should be preserved but the `use` or
323 `ptruse` parts replaced, then we use an ellipsis for the declaration part:
324
325 prefix__type = ... | use | ptruse
326
327 This is useful to map schema polymorphic types to C types for example, where we
328 need to be able to both handle a base type and its extensions as per schema
329 extensibility. Say we have a base type called `ns:base` that is extended, then
330 we can remap this to a C type that permits referening the extended types via a
331 `void*` as follows:
332
333 ns__base = ... | int __type_base; void*
334
335 such that `__type_base` and `void*` will be used to (de)serialize any data
336 type, including base and its derived types. The `__type_base` integer is set
337 to a `SOAP_TYPE_T` value to indicate what type of data the `void*` pointer
338 points to.
339
340 🔝 [Back to table of contents](#)
341
342 Custom serializers for XSD types {#custom}
343 --------------------------------
344
345 In the previous part we saw how a custom serializer is used to bind
346 `xsd:duration` to a `long long` (`LONG64` or `int64_t`) type to store millisecond
347 duration values:
348
349 xsd__duration = #import "custom/duration.h"
350
351 The `xsd__duration` type is an alias of `long long` (`LONG64` or `int64_t`).
352
353 While wsdl2h will use this binding declared in `typemap.dat` automatically, you
354 will also need to compile `custom/duration.c`. Each custom serializer has a
355 header file and an implementation file written in C. You can compile these in
356 C++ (rename files to `.cpp` if needed).
357
358 We will discuss the custom serializers that are available to you.
359
360 🔝 [Back to table of contents](#)
361
362 ### xsd:integer {#custom-1}
363
364 The wsdl2h tool maps `xsd:integer` to a string by default. To map `xsd:integer` to
365 the 128 bit big int type `__int128_t`:
366
367 xsd__integer = #import "custom/int128.h"
368
369 The `xsd__integer` type is an alias of `__int128_t`.
370
371 @warning Beware that the `xsd:integer` value space of integers is in principle
372 unbounded and values can be of arbitrary length. A value range fault
373 `SOAP_TYPE` (value exceeds native representation) or `SOAP_LENGTH` (value
374 exceeds range bounds) will be thrown by the deserializer if the value is out of
375 range.
376
377 Other XSD integer types that are restrictions of `xsd:integer`, are
378 `xsd:nonNegativeInteger` and `xsd:nonPositiveInteger`, which are further restricted
379 by `xsd:positiveInteger` and `xsd:negativeInteger`. To bind these types to
380 `__int128_t` add the following definitions to `typemap.dat`:
381
382 xsd__nonNegativeInteger = typedef xsd__integer xsd__nonNegativeInteger 0 : ;
383 xsd__nonPositiveInteger = typedef xsd__integer xsd__nonPositiveInteger : 0 ;
384 xsd__positiveInteger = typedef xsd__integer xsd__positiveInteger 1 : ;
385 xsd__negativeInteger = typedef xsd__integer xsd__negativeInteger : -1 ;
386
387 Or simply uncomment these definitions in `typemap.dat` when you are using the
388 latest gSOAP releases.
389
390 @note If `__int128_t` 128 bit integers are not supported on your platform and if it
391 is certain that `xsd:integer` values are within 64 bit value bounds for your
392 application's use, then you can map this type to `LONG64`:
393
394 xsd__integer = typedef LONG64 xsd__integer;
395
396 @note Again, a value range fault `SOAP_TYPE` or `SOAP_LENGTH` will be thrown by
397 the deserializer if the value is out of range.
398
399 After running wsdl2h and soapcpp2, compile `custom/int128.c` with your project.
400
401 @see Section [numerical types](#toxsd5).
402
403 🔝 [Back to table of contents](#)
404
405 ### xsd:decimal {#custom-2}
406
407 The wsdl2h tool maps `xsd:decimal` to a string by default. To map `xsd:decimal` to
408 extended precision floating point:
409
410 xsd__decimal = #import "custom/long_double.h" | long double
411
412 By contrast to all other custom serializers, this serializer enables `long
413 double` natively without requiring a new binding name (`xsd__decimal` is NOT
414 defined).
415
416 If your system supports `<quadmath.h>` quadruple precision floating point
417 `__float128`, you can map `xsd:decimal` to `xsd__decimal` that is an alias of
418 `__float128`:
419
420 xsd__decimal = #import "custom/float128.h"
421
422 @warning Beware that `xsd:decimal` is in principle a decimal value with arbitraty
423 lengths. A value range fault `SOAP_TYPE` will be thrown by the deserializer if
424 the value is out of range.
425
426 In the XML payload the special values `INF`, `-INF`, `NaN` represent plus or
427 minus infinity and not-a-number, respectively.
428
429 After running wsdl2h and soapcpp2, compile `custom/long_double.c` with your
430 project.
431
432 @see Section [numerical types](#toxsd5).
433
434 🔝 [Back to table of contents](#)
435
436 ### xsd:dateTime {#custom-3}
437
438 The wsdl2h tool maps `xsd:dateTime` to `time_t` by default.
439
440 The trouble with `time_t` when represented as 32 bit `long` integers is that it
441 is limited to dates between 1970 and 2038. A 64 bit `time_t` is safe to use if
442 the target platform supports it, but lack of 64 bit `time_t` portability may
443 still cause date range issues.
444
445 For this reason `struct tm` should be used to represent wider date ranges. This
446 custom serializer avoids using date and time information in `time_t`. You get
447 the raw date and time information. You only lose the day of the week
448 information. It is always Sunday (`tm_wday=0`).
449
450 To map `xsd:dateTime` to `xsd__dateTime` which is an alias of `struct tm`:
451
452 xsd__dateTime = #import "custom/struct_tm.h"
453
454 If the limited date range of `time_t` is not a problem but you want to increase
455 the time precision with fractional seconds, then we suggest to map `xsd:dateTime`
456 to `struct timeval`:
457
458 xsd__dateTime = #import "custom/struct_timeval.h"
459
460 If the limited date range of `time_t` is not a problem but you want to use the
461 C++11 time point type `std::chrono::system_clock::time_point` (which internally
462 uses `time_t`):
463
464 xsd__dateTime = #import "custom/chrono_time_point.h"
465
466 Again, we should make sure that the dates will not exceed the date range when
467 using the default `time_t` binding for `xsd:dateTime` or when binding
468 `xsd:dateTime` to `struct timeval` or to `std::chrono::system_clock::time_point`.
469 These are safe to use in applications that use `xsd:dateTime` to record date
470 stamps within a given window. Otherwise, we recommend the `struct tm` custom
471 serializer.
472
473 After running wsdl2h and soapcpp2, compile `custom/struct_tm.c` with your
474 project.
475
476 You could even map `xsd:dateTime` to a plain string (use `char*` with C and
477 `std::string` with C++). For example:
478
479 xsd__dateTime = | char*
480
481 @see Section [date and time types](#toxsd7).
482
483 🔝 [Back to table of contents](#)
484
485 ### xsd:date {#custom-4}
486
487 The wsdl2h tool maps `xsd:date` to a string by default. We can map `xsd:date` to
488 `struct tm`:
489
490 xsd__date = #import "custom/struct_tm_date.h"
491
492 The `xsd__date` type is an alias of `struct tm`. The serializer ignores the
493 time part and the deserializer only populates the date part of the struct,
494 setting the time to 00:00:00. There is no unreasonable limit on the date range
495 because the year field is stored as an integer (`int`).
496
497 After running wsdl2h and soapcpp2, compile `custom/struct_tm_date.c` with your
498 project.
499
500 @see Section [date and time types](#toxsd7).
501
502 🔝 [Back to table of contents](#)
503
504 ### xsd:time {#custom-5}
505
506 The wsdl2h tool maps `xsd:time` to a string by default. We can map `xsd:time` to
507 an `unsigned long long` (`ULONG64` or `uint64_t`) integer with microsecond time
508 precision:
509
510 xsd__time = #import "custom/long_time.h"
511
512 This type represents 00:00:00.000000 to 23:59:59.999999, from `0` to an upper
513 bound of `86399999999`. A microsecond resolution means that a 1 second
514 increment requires an increment of 1000000 in the integer value. The serializer
515 adds a UTC time zone.
516
517 After running wsdl2h and soapcpp2, compile `custom/long_time.c` with your
518 project.
519
520 @see Section [date and time types](#toxsd7).
521
522 🔝 [Back to table of contents](#)
523
524 ### xsd:duration {#custom-6}
525
526 The wsdl2h tool maps `xsd:duration` to a string by default, unless `xsd:duration`
527 is mapped to a `long long` (`LONG64` or `int64_t`) type with with millisecond
528 (ms) time duration precision:
529
530 xsd__duration = #import "custom/duration.h"
531
532 The `xsd__duration` type is a 64 bit signed integer that can represent
533 106,751,991,167 days forwards (positive) and backwards (negative) in time in
534 increments of 1 ms (1/1000 of a second).
535
536 Rescaling of the duration value by may be needed when adding the duration value
537 to a `time_t` value, because `time_t` may or may not have a seconds resolution,
538 depending on the platform and possible changes to `time_t`.
539
540 Rescaling is done automatically when you add a C++11 `std::chrono::nanoseconds`
541 value to a `std::chrono::system_clock::time_point` value. To use
542 `std::chrono::nanoseconds` as `xsd:duration`:
543
544 xsd__duration = #import "custom/chrono_duration.h"
545
546 This type can represent 384,307,168 days (2^63 nanoseconds) forwards and
547 backwards in time in increments of 1 ns (1/1,000,000,000 of a second).
548
549 Certain observations with respect to receiving durations in years and months
550 apply to both of these serializer decoders for `xsd:duration`.
551
552 After running wsdl2h and soapcpp2, compile `custom/duration.c` with your
553 project.
554
555 @see Section [time duration types](#toxsd8).
556
557 🔝 [Back to table of contents](#)
558
559 Custom Qt serializers for XSD types {#qt}
560 -----------------------------------
561
562 The gSOAP distribution includes several custom serializers for Qt types. Also
563 Qt container classes are supported, see
564 [the built-in typemap.dat variables $CONTAINER and $POINTER](#typemap5).
565
566 This feature requires gSOAP 2.8.34 or higher and Qt 4.8 or higher.
567
568 Each Qt custom serializer has an interface header file for soapcpp2 and a C++
569 implementation file to be compiled with your project.
570
571 Other Qt primitive types that are Qt typedefs of C/C++ types do not require a
572 custom serializer.
573
574 🔝 [Back to table of contents](#)
575
576 ### xsd:string {#qt-1}
577
578 To use Qt strings instead of C++ strings, add the following definition to
579 `typemap.dat`:
580
581 xsd__string = #import "custom/qstring.h"
582
583 After running wsdl2h and soapcpp2, compile `custom/qstring.cpp` with your
584 project.
585
586 🔝 [Back to table of contents](#)
587
588 ### xsd:base64Binary {#qt-2}
589
590 To use Qt byte arrays for `xsd:base64Binary` instead of the
591 `xsd__base64Binary` class, add the following definition to `typemap.dat`:
592
593 xsd__base64Binary = #import "custom/qbytearray_base64.h"
594
595 After running wsdl2h and soapcpp2, compile `custom/qbytearray_base64.cpp` with
596 your project.
597
598 🔝 [Back to table of contents](#)
599
600 ### xsd:hexBinary {#qt-3}
601
602 To use Qt byte arrays for `xsd:hexBinary` instead of the `xsd__base64Binary`
603 class, add the following definition to `typemap.dat`:
604
605 xsd__hexBinary = #import "custom/qbytearray_hex.h"
606
607 After running wsdl2h and soapcpp2, compile `custom/qbytearray_hex.cpp` with
608 your project.
609
610 🔝 [Back to table of contents](#)
611
612 ### xsd:dateTime {#qt-4}
613
614 To use Qt QDateTime for `xsd:dateTime`, add the following definition to
615 `typemap.dat`:
616
617 xsd__dateTime = #import "custom/datetime.h"
618
619 After running wsdl2h and soapcpp2, compile `custom/qdatetime.cpp` with
620 your project.
621
622 🔝 [Back to table of contents](#)
623
624 ### xsd:date {#qt-5}
625
626 To use Qt QDate for `xsd:date`, add the following definition to
627 `typemap.dat`:
628
629 xsd__date = #import "custom/qdate.h"
630
631 After running wsdl2h and soapcpp2, compile `custom/qdate.cpp` with your
632 project.
633
634 🔝 [Back to table of contents](#)
635
636 ### xsd:time {#qt-6}
637
638 To use Qt QDate for `xsd:time`, add the following definition to
639 `typemap.dat`:
640
641 xsd__time = #import "custom/qtime.h"
642
643 After running wsdl2h and soapcpp2, compile `custom/qtime.cpp` with your
644 project.
645
646 🔝 [Back to table of contents](#)
647
648 Class/struct member additions {#typemap3}
649 -----------------------------
650
651 All generated classes and structs can be augmented with additional
652 members such as methods, constructors and destructors, and private members:
653
654 prefix__type = $ member-declaration
655
656 For example, we can add method declarations and private members to a class, say
657 `ns__record` as follows:
658
659 ns__record = $ ns__record(const ns__record &); // copy constructor
660 ns__record = $ void print(); // a print method
661 ns__record = $ private: int status; // a private member
662
663 Note that method declarations cannot include any code, because soapcpp2's input
664 permits only type declarations, not code.
665
666 🔝 [Back to table of contents](#)
667
668 Replacing XSD types by equivalent alternatives {#typemap4}
669 ----------------------------------------------
670
671 Type replacements can be given to replace one type entirely with another given
672 type:
673
674 prefix__type1 == prefix__type2
675
676 This replaces all `prefix__type1` by `prefix__type2` in the wsdl2h output.
677
678 @warning Do not agressively replace types, because this can cause XML schema
679 validation to fail when a value-type mismatch is encountered in the XML input.
680 Therefore, only replace similar types with other similar types that are wider
681 (e.g. `short` by `int` and `float` by `double`).
682
683 🔝 [Back to table of contents](#)
684
685 The built-in typemap.dat variables $CONTAINER and $POINTER {#typemap5}
686 ----------------------------------------------------------
687
688 The `typemap.dat` `$CONTAINER` variable defines the container to emit in the
689 generated declarations, which is `std::vector` by default. For example, to emit
690 `std::list` as the container in the wsdl2h-generated declarations:
691
692 $CONTAINER = std::list
693
694 The `typemap.dat` `$POINTER` variable defines the smart pointer to emit in the
695 generated declarations, which replaces the use of `*` pointers. For example:
696
697 $POINTER = std::shared_ptr
698
699 Not all pointers in the generated output can be replaced by smart pointers.
700 Regular pointers are still used as union members and for pointers to arrays of
701 objects.
702
703 @note The standard smart pointer `std::shared_ptr` is generally safe to use.
704 Other smart pointers such as `std::unique_ptr` and `std::auto_ptr` may cause
705 compile-time errors when classes have smart pointer members but no copy
706 constructor (a default copy constructor). A copy constructor is required for
707 non-shared smart pointer copying or swapping.
708
709 Alternatives to `std::shared_ptr` of the form `NAMESPACE::shared_ptr` can be
710 assigned to `$POINTER` when the namespace `NAMESPACE` also implements
711 `NAMESPACE::make_shared` and when the shared pointer class provides `reset()`
712 and`get()` methods and the dereference operator. For example Boost
713 `boost::shared_ptr`:
714
715 [
716 #include <boost/shared_ptr.hpp>
717 ]
718 $POINTER = boost::shared_ptr
719
720 The user-defined content between `[` and `]` ensures that we include the Boost
721 header files that are needed to support `boost::shared_ptr` and
722 `boost::make_shared`.
723
724 A Qt container can be used instead of the default `std::vector`, for example
725 `QVector`:
726
727 [
728 #include <QVector>
729 ]
730 $CONTAINER = QVector
731
732 🔝 [Back to table of contents](#)
733
734 User-defined content {#typemap6}
735 --------------------
736
737 Any other content to be generated by wsdl2h can be included in `typemap.dat` by
738 enclosing it within brackets `[` and `]` anywhere in the `typemap.dat` file.
739 Each of the two brackets MUST appear at the start of a new line.
740
741 For example, we can add an `#import "wsa5.h"` to the wsdl2h-generated output as
742 follows:
743
744 [
745 #import "import/wsa5.h"
746 ]
747
748 which emits the `#import "import/wsa5.h"` literally at the start of the
749 wsdl2h-generated header file.
750
751 🔝 [Back to table of contents](#)
752
753 Mapping C/C++ to XML schema {#toxsd}
754 ===========================
755
756 The soapcpp2 command generates the data binding implementation code from a data
757 binding interface `file.h`:
758
759 soapcpp2 [options] file.h
760
761 where `file.h` is a gSOAP header file that declares the XML data binding
762 interface. The `file.h` is typically generated by wsdl2h, but you can also
763 declare one yourself. If so, add `//gsaop` [directives](#directives) and
764 declare in this file all our C/C++ types you want to serialize in XML.
765
766 You can also declare functions that will be converted to Web service operations
767 by soapcpp2. Global function declarations define service operations, which are
768 of the form:
769
770 ```cpp
771 int prefix__func(arg1, arg2, ..., argn, result);
772 ```
773
774 where `arg1`, `arg2`, ..., `argn` are formal argument declarations of the input
775 and `result` is a formal argument for the output, which must be a pointer or
776 reference to the result object to be populated. More information can be found
777 in the [gSOAP user guide.](http://www.genivia.com/doc/soapdoc2.html)
778
779 🔝 [Back to table of contents](#)
780
781 Overview of serializable C/C++ types {#toxsd1}
782 ------------------------------------
783
784 The following C/C++ types are supported by soapcpp2 and mapped to XSD types
785 and constructs. See the subsections below for more details or follow the links.
786
787 🔝 [Back to table of contents](#)
788
789 ### List of Boolean types
790
791 Boolean Type | Notes
792 ----------------------------- | -----
793 `bool` | C++ bool
794 `enum xsd__boolean` | C alternative to C++ `bool` with `false_` and `true_`
795
796 @see Section [C++ bool and C alternative](#toxsd3).
797
798 🔝 [Back to table of contents](#)
799
800 ### List of enumeration and bitmask types
801
802 Enumeration Type | Notes
803 ----------------------------- | -----
804 `enum` | enumeration
805 `enum class` | C++11 scoped enumeration (soapcpp2 `-c++11`)
806 `enum*` | a bitmask that enumerates values 1, 2, 4, 8, ...
807 `enum* class` | C++11 scoped enumeration bitmask (soapcpp2 `-c++11`)
808
809 @see Section [enumerations and bitmasks](#toxsd4).
810
811 🔝 [Back to table of contents](#)
812
813 ### List of numerical types
814
815 Numerical Type | Notes
816 ----------------------------- | -----
817 `char` | byte
818 `short` | 16 bit integer
819 `int` | 32 bit integer
820 `long` | 32 bit integer
821 `LONG64` | 64 bit integer
822 `xsd__integer` | 128 bit integer, use `#import "custom/int128.h"`
823 `long long` | same as `LONG64`
824 `unsigned char` | unsigned byte
825 `unsigned short` | unsigned 16 bit integer
826 `unsigned int` | unsigned 32 bit integer
827 `unsigned long` | unsigned 32 bit integer
828 `ULONG64` | unsigned 64 bit integer
829 `unsigned long long` | same as `ULONG64`
830 `int8_t` | same as `char`
831 `int16_t` | same as `short`
832 `int32_t` | same as `int`
833 `int64_t` | same as `LONG64`
834 `uint8_t` | same as `unsigned char`
835 `uint16_t` | same as `unsigned short`
836 `uint32_t` | same as `unsigned int`
837 `uint64_t` | same as `ULONG64`
838 `size_t` | transient type (not serializable)
839 `float` | 32 bit float
840 `double` | 64 bit float
841 `long double` | extended precision float, use `#import "custom/long_double.h"`
842 `xsd__decimal` | `<quadmath.h>` 128 bit quadruple precision float, use `#import "custom/float128.h"`
843 `typedef` | declares a type name, with optional value range and string length bounds
844
845 @see Section [numerical types](#toxsd5).
846
847 🔝 [Back to table of contents](#)
848
849 ### List of string types
850
851 String Type | Notes
852 ----------------------------- | -----
853 `char*` | string (may contain UTF-8 with flag `SOAP_C_UTFSTRING`)
854 `wchar_t*` | wide string
855 `std::string` | C++ string (may contain UTF-8 with flag `SOAP_C_UTFSTRING`)
856 `std::wstring` | C++ wide string
857 `char[N]` | fixed-size string, requires soapcpp2 option `-b`
858 `_QName` | normalized QName content
859 `_XML` | literal XML string content with wide characters in UTF-8
860 `typedef` | declares a new string type name, may restrict string length
861
862 @see Section [string types](#toxsd6).
863
864 🔝 [Back to table of contents](#)
865
866 ### List of date and time types
867
868 Date and Time Type | Notes
869 --------------------------------------- | -----
870 `time_t` | date and time point since epoch
871 `struct tm` | date and time point, use `#import "custom/struct_tm.h"`
872 `struct tm` | date point, use `#import "custom/struct_tm_date.h"`
873 `struct timeval` | date and time point, use `#import "custom/struct_timeval.h"`
874 `unsigned long long` | time point in microseconds, use `#import "custom/long_time.h"`
875 `std::chrono::system_clock::time_point` | date and time point, use `#import "custom/chrono_time_point.h"`
876
877 @see Section [date and time types](#toxsd7).
878
879 🔝 [Back to table of contents](#)
880
881 ### List of time duration types
882
883 Time Duration Type | Notes
884 ----------------------------- | -----
885 `long long` | duration in milliseconds, use `#import "custom/duration.h"`
886 `std::chrono::nanoseconds` | duration in nanoseconds, use `#import "custom/chrono_duration.h"`
887
888 @see Section [time duration types](#toxsd8).
889
890 🔝 [Back to table of contents](#)
891
892 ### List of classes and structs
893
894 Classes, Structs, and Members | Notes
895 ----------------------------- | -----
896 `class` | C++ class with single inheritance only
897 `struct` | C struct or C++ struct without inheritance
898 `std::shared_ptr<T>` | C++11 smart shared pointer
899 `std::unique_ptr<T>` | C++11 smart pointer
900 `std::auto_ptr<T>` | C++ smart pointer
901 `std::deque<T>` | use `#import "import/stldeque.h"`
902 `std::list<T>` | use `#import "import/stllist.h"`
903 `std::vector<T>` | use `#import "import/stlvector.h"`
904 `std::set<T>` | use `#import "import/stlset.h"`
905 `template<T> class` | a container with `begin()`, `end()`, `size()`, `clear()`, and `insert()` methods
906 `T*` | data member: pointer to data of type `T` or points to array of `T` of size `__size`
907 `T[N]` | data member: fixed-size array of type `T`
908 `union` | data member: requires a variant selector member `__union`
909 `void*` | data member: requires a `__type` member to indicate the type of object pointed to
910
911 @see Section [classes and structs](#toxsd9).
912
913 🔝 [Back to table of contents](#)
914
915 ### List of special classes and structs
916
917 Special Classes and Structs | Notes
918 ----------------------------- | -----
919 Special Array class/struct | single and multidimensional SOAP Arrays
920 Special Wrapper class/struct | complexTypes with simpleContent, wraps `__item` member
921 `xsd__hexBinary` | binary content
922 `xsd__base64Binary` | binary content and optional MIME/MTOM attachments
923 `xsd__anyType` | DOM elements, use `#import "dom.h"`
924 `@xsd__anyAttribute` | DOM attributes, use `#import "dom.h"`
925
926 @see Section [special classes and structs](#toxsd10).
927
928 🔝 [Back to table of contents](#)
929
930 Colon notation versus name prefixing with XML tag name translation {#toxsd2}
931 ------------------------------------------------------------------
932
933 To bind C/C++ type names to XSD types, a simple form of name prefixing is used
934 by the gSOAP tools by prepending the XML namespace prefix to the C/C++ type
935 name with a pair of undescrores. This also ensures that name clashes cannot
936 occur when multiple WSDL and XSD files are converted to C/C++. Also, C++
937 namespaces are not sufficiently rich to capture XML schema namespaces
938 accurately, for example when class members are associated with schema elements
939 defined in another XML namespace and thus the XML namespace scope of the
940 member's name is relevant, not just its type.
941
942 However, from a C/C++ centric point of view this can be cumbersome. Therefore,
943 colon notation is an alternative to physically augmenting C/C++ names with
944 prefixes.
945
946 For example, the following class uses colon notation to bind the `record` class
947 to the `urn:types` schema:
948
949 ```cpp
950 //gsoap ns schema namespace: urn:types
951 class ns:record // binding 'ns:' to a type name
952 {
953 public:
954 std::string name;
955 uint64_t SSN;
956 ns:record *spouse; // using 'ns:' with the type name
957 ns:record(); // using 'ns:' here too
958 ~ns:record(); // and here
959 };
960 ```
961
962 The colon notation is stripped away by soapcpp2 when generating the data
963 binding implementation code for our project. So the final code just uses
964 `record` to identify this class and its constructor/destructor.
965
966 When using colon notation make sure to be consistent and not use colon notation
967 mixed with prefixed forms. The name `ns:record` differs from `ns__record`,
968 because `ns:record` is compiled to an unqualified `record` name.
969
970 Colon notation also facilitates overruling the elementFormDefault and
971 attributeFormDefault declaration that is applied to local elements and
972 attributes, when declared as members of classes, structs, and unions. For more
973 details, see [qualified and unqualified members](#toxsd9-6).
974
975 A C/C++ identifier name (a type name, member name, function name, or parameter
976 name) is translated to an XML tag name by the following rules:
977
978 - Two leading underscores indicates that the identifier name has no XML tag
979 name, i.e. this name is not visible in XML and is not translated.
980 - A leading underscore is removed, but the underscore indicates that: **a**) a
981 struct/class member name or parameter name has a wildcard XML tag name (i.e.
982 matches any XML tag), or **b**) a type name that has a
983 [document root element definition](#toxsd9-7).
984 - Trailing underscores are removed (i.e. trailing underscores can be used to
985 avoid name clashes with keywords).
986 - Underscores within names are translated to hyphens (hyphens are more common
987 in XML tags).
988 - `_USCORE` is translated to an underscore in the translated XML tag name.
989 - `_DOT` is translated to a dot (`.`) in the translated XML tag name.
990 - `_xHHHH` is translated to the Unicode character with code point HHHH (hex).
991 - C++11 Unicode identifier name characters in UTF-8 are translated as-is.
992
993 For example, the C/C++ namespace qualified identifier name `s_a__my_way` is
994 translated to the XML tag name `s-a:my-way` by translating the prefix `s_a`
995 and the local name `my_way`.
996
997 Struct/class member and parameter name translation can be overruled by using
998 [backtick XML tags](#toxsd9-5) (with gSOAP 2.8.30 and later versions).
999
1000 🔝 [Back to table of contents](#)
1001
1002 C++ Bool and C alternatives {#toxsd3}
1003 ---------------------------
1004
1005 The C++ `bool` type is bound to built-in XSD type `xsd:boolean`.
1006
1007 The C alternative is to define an enumeration:
1008
1009 ```cpp
1010 enum xsd__boolean { false_, true_ };
1011 ```
1012
1013 or by defining an enumeration in C with pseudo-scoped enumeration constants:
1014
1015 ```cpp
1016 enum xsd__boolean { xsd__boolean__false, xsd__boolean__true };
1017 ```
1018
1019 The XML value space of these types is `false` and `true`, but also accepted
1020 are `0` and `1` values for false and true, respectively.
1021
1022 To prevent name clashes, `false_` and `true_` have an underscore. Trailing
1023 underscores are removed from the XML value space.
1024
1025 🔝 [Back to table of contents](#)
1026
1027 Enumerations and bitmasks {#toxsd4}
1028 -------------------------
1029
1030 Enumerations are mapped to XSD simpleType enumeration restrictions of
1031 `xsd:string`, `xsd:QName`, and `xsd:long`.
1032
1033 Consider for example:
1034
1035 ```cpp
1036 enum ns__Color { RED, WHITE, BLUE };
1037 ```
1038
1039 which maps to a simpleType restriction of `xsd:string` in the soapcpp2-generated
1040 schema:
1041
1042 <div class="alt">
1043 ```xml
1044 <simpleType name="Color">
1045 <restriction base="xsd:string">
1046 <enumeration value="RED"/>
1047 <enumeration value="WHITE"/>
1048 <enumeration value="BLUE"/>
1049 </restriction>
1050 </simpleType>
1051 ```
1052 </div>
1053
1054 Enumeration name constants can be pseudo-scoped to prevent name clashes,
1055 because enumeration name constants have a global scope in C and C++:
1056
1057 ```cpp
1058 enum ns__Color { ns__Color__RED, ns__Color__WHITE, ns__Color__BLUE };
1059 ```
1060
1061 You can also use C++11 scoped enumerations to prevent name clashes:
1062
1063 ```cpp
1064 enum class ns__Color : int { RED, WHITE, BLUE };
1065 ```
1066
1067 Here, the enumeration class base type `: int` is optional. In place of `int`
1068 in the example above, we can also use `int8_t`, `int16_t`, `int32_t`, or
1069 `int64_t`.
1070
1071 The XML value space of the enumertions defined above is `RED`, `WHITE`, and
1072 `BLUE`.
1073
1074 Prefix-qualified enumeration name constants are mapped to simpleType
1075 restrictions of `xsd:QName`, for example:
1076
1077 ```cpp
1078 enum ns__types { xsd__int, xsd__float };
1079 ```
1080
1081 which maps to a simpleType restriction of `xsd:QName` in the soapcpp2-generated
1082 schema:
1083
1084 <div class="alt">
1085 ```xml
1086 <simpleType name="types">
1087 <restriction base="xsd:QName">
1088 <enumeration value="xsd:int"/>
1089 <enumeration value="xsd:float"/>
1090 </restriction>
1091 </simpleType>
1092 ```
1093 </div>
1094
1095 Enumeration name constants can be pseudo-numeric as follows:
1096
1097 ```cpp
1098 enum ns__Primes { _3 = 3, _5 = 5, _7 = 7, _11 = 11 };
1099 ```
1100
1101 which maps to a simpleType restriction of `xsd:long`:
1102
1103 <div class="alt">
1104 ```xml
1105 <simpleType name="Color">
1106 <restriction base="xsd:long">
1107 <enumeration value="3"/>
1108 <enumeration value="5"/>
1109 <enumeration value="7"/>
1110 <enumeration value="11"/>
1111 </restriction>
1112 </simpleType>
1113 ```
1114 </div>
1115
1116 The XML value space of this type is `3`, `5`, `7`, and `11`.
1117
1118 Besides (pseudo-) scoped enumerations, another way to prevent name clashes
1119 accross enumerations is to start an enumeration name constant with one
1120 underscore or followed it by any number of underscores, which makes it
1121 unique. The leading and trailing underscores are removed from the XML value
1122 space.
1123
1124 ```cpp
1125 enum ns__ABC { A, B, C };
1126 enum ns__BA { B, A }; // BAD: B = 1 but B is already defined as 2
1127 enum ns__BA_ { B_, A_ }; // OK
1128 ```
1129
1130 The gSOAP soapcpp2 tool permits reusing enumeration name constants across
1131 (non-scoped) enumerations as long as these values are assigned the same
1132 constant. Therefore, the following is permitted:
1133
1134 ```cpp
1135 enum ns__Primes { _3 = 3, _5 = 5, _7 = 7, _11 = 11 };
1136 enum ns__Throws { _1 = 1, _2 = 2, _3 = 3, _4 = 4, _5 = 5, _6 = 6 };
1137 ```
1138
1139 A bitmask type is an `enum*` "product" enumeration with a geometric,
1140 power-of-two sequence of values assigned to the enumeration constants:
1141
1142 ```cpp
1143 enum* ns__Options { SSL3, TLS10, TLS11, TLS12 };
1144 ```
1145
1146 where the product enum assigns 1 to `SSL3`, 2 to `TLS10`, 4 to `TLS11`, and 8
1147 to `TLS12`, which allows these enumeration constants to be used in composing
1148 bitmasks with `|` (bitwise or) `&` (bitwise and), and `~` (bitwise not):
1149
1150 ```cpp
1151 enum ns__Options options = (enum ns__Options)(SSL3 | TLS10 | TLS11 | TLS12);
1152 if (options & SSL3) // if SSL3 is an option, warn and remove from options
1153 {
1154 warning();
1155 options &= ~SSL3;
1156 }
1157 ```
1158
1159 The bitmask type maps to a simpleType list restriction of `xsd:string` in the
1160 soapcpp2-generated schema:
1161
1162 <div class="alt">
1163 ```xml
1164 <simpleType name="Options">
1165 <list>
1166 <restriction base="xsd:string">
1167 <enumeration value="SSL3"/>
1168 <enumeration value="TLS10"/>
1169 <enumeration value="TLS11"/>
1170 <enumeration value="TLS12"/>
1171 </restriction>
1172 </list>
1173 </simpleType>
1174 ```
1175 </div>
1176
1177 The XML value space of this type consists of all 16 possible subsets of the
1178 four values, represented by an XML string with space-separated values. For
1179 example, the bitmask `TLS10 | TLS11 | TLS12` equals 14 and is represented by
1180 the XML string `TLS10 TLS11 TLS12`.
1181
1182 You can also use C++11 scoped enumerations with bitmasks:
1183
1184 ```cpp
1185 enum* class ns__Options { SSL3, TLS10, TLS11, TLS12 };
1186 ```
1187
1188 The base type of a scoped enumeration bitmask, when explicitly given, is
1189 ignored. The base type is either `int` or `int64_t`, depending on the number
1190 of constants enumerated in the bitmask.
1191
1192 To convert `enum` name constants and bitmasks to a string, we use the
1193 auto-generated function for enum `T`:
1194
1195 ```cpp
1196 const char *soap_T2s(struct soap*, enum T val)
1197 ```
1198
1199 The string returned is stored in an internal buffer of the current `soap`
1200 context, so you MUST copy it to keep it from being overwritten. For example,
1201 use `char *soap_strdup(struct soap*, const char*)`.
1202
1203 To convert a string to an `enum` constant or bitmask, we use the auto-generated
1204 function
1205
1206 ```cpp
1207 int soap_s2T(struct soap*, const char *str, enum T *val)
1208 ```
1209
1210 This function takes the name (or names, space-separated for bitmasks) of
1211 the enumeration constant in a string `str`. Names should be given without the
1212 pseudo-scope prefix and without trailing underscores. The function sets `val`
1213 to the corresponding integer enum constant or to a bitmask. The function
1214 returns `SOAP_OK` (zero) on success or an error if the string is not a valid
1215 enumeration name.
1216
1217 🔝 [Back to table of contents](#)
1218
1219 Numerical types {#toxsd5}
1220 ---------------
1221
1222 Integer and floating point types are mapped to the equivalent built-in XSD
1223 types with the same sign and bit width.
1224
1225 The `size_t` type is transient (not serializable) because its width is platform
1226 dependent. We recommend to use `uint64_t` instead.
1227
1228 The XML value space of integer types are their decimal representations without
1229 loss of precision.
1230
1231 The XML value space of floating point types are their decimal representations.
1232 The decimal representations are formatted with the printf format string "%.9G"
1233 for floats and the printf format string "%.17lG" for double. To change the
1234 format strings, we can assign new strings to the following `struct soap`
1235 context members:
1236
1237 ```cpp
1238 soap.float_format = "%g";
1239 soap.double_format = "%lg";
1240 soap.long_double_format = "%Lg";
1241 ```
1242
1243 Note that decimal representations may result in a loss of precision of the
1244 least significant decimal. Therefore, the format strings that are used by
1245 default are sufficiently precise to avoid loss, but this may result in long
1246 decimal fractions in the XML value space.
1247
1248 The `long double` extended floating point type requires a custom serializer:
1249
1250 ```cpp
1251 #import "custom/long_double.h"
1252 ... use long double ...
1253 ```
1254
1255 You can now use `long double`, which has a serializer that serializes this type
1256 as `xsd:decimal`. Compile and link your code with `custom/long_double.c`.
1257
1258 The value space of floating point values includes the special values `INF`,
1259 `-INF`, and `NaN`. You can check a value for plus or minus infinity and
1260 not-a-number as follows:
1261
1262 ```cpp
1263 soap_isinf(x) && x > 0 // is x INF?
1264 soap_isinf(x) && x < 0 // is x -INF?
1265 soap_isnan(x) // is x NaN?
1266 ```
1267
1268 To assign these values, use:
1269
1270 ```cpp
1271 // x is float // x is double, long double, or __float128
1272 x = FLT_PINFY; x = DBL_PINFTY;
1273 x = FLT_NINFY; x = DBL_NINFTY;
1274 x = FLT_NAN; x = DBL_NAN;
1275 ```
1276
1277 If your system supports `__float128` then you can also use this 128 bit
1278 floating point type with a custom serializer:
1279
1280 ```cpp
1281 #import "custom/float128.h"
1282 ... use xsd__decimal ...
1283 ```
1284
1285 Then use the `xsd__decimal` alias of `__float128`, which has a serializer. Do
1286 not use `__float128` directly, which is transient (not serializable).
1287
1288 To check for `INF`, `-INF`, and `NaN` of a `__float128` value use:
1289
1290 ```cpp
1291 isinfq(x) && x > 0 // is x INF?
1292 isinfq(x) && x < 0 // is x -INF?
1293 isnanq(x) // is x NaN?
1294 ```
1295
1296 The range of a typedef-defined numerical type can be restricted using the range
1297 `:` operator with inclusive lower and upper bounds. For example:
1298
1299 ```cpp
1300 typedef int ns__narrow -10 : 10;
1301 ```
1302
1303 This maps to a simpleType restriction of `xsd:int` in the soapcpp2-generated
1304 schema:
1305
1306 <div class="alt">
1307 ```xml
1308 <simpleType name="narrow">
1309 <restriction base="xsd:int">
1310 <minInclusive value="-10"/>
1311 <maxInclusive value="10"/>
1312 </restriction>
1313 </simpleType>
1314 ```
1315 </div>
1316
1317 The lower and upper bound of a range are optional. When omitted, values are
1318 not bound from below or from above, respectively.
1319
1320 The range of a floating point typedef-defined type can be restricted within
1321 floating point constant bounds.
1322
1323 Also with a floating point typedef a printf format pattern can be given of the
1324 form `"%[width][.precision]f"` to format decimal values using the given width
1325 and precision fields:
1326
1327 ```cpp
1328 typedef float ns__PH "%5.2f" 0.0 : 14.0;
1329 ```
1330
1331 This maps to a simpleType restriction of `xsd:float` in the soapcpp2-generated
1332 schema:
1333
1334 <div class="alt">
1335 ```xml
1336 <simpleType name="PH">
1337 <restriction base="xsd:float">
1338 <totalDigits value="5"/>
1339 <fractionDigits value="2"/>
1340 <minInclusive value="0"/>
1341 <maxInclusive value="14"/>
1342 </restriction>
1343 </simpleType>
1344 ```
1345 </div>
1346
1347 For exclusive bounds, we use the `<` operator instead of the `:` range
1348 operator:
1349
1350 ```cpp
1351 typedef float ns__epsilon 0.0 < 1.0;
1352 ```
1353
1354 Values `eps` of `ns__epsilon` are restricted between `0.0 < eps < 1.0`.
1355
1356 This maps to a simpleType restriction of `xsd:float` in the soapcpp2-generated
1357 schema:
1358
1359 <div class="alt">
1360 ```xml
1361 <simpleType name="epsilon">
1362 <restriction base="xsd:float">
1363 <minExclusive value="0"/>
1364 <maxExclusive value="1"/>
1365 </restriction>
1366 </simpleType>
1367 ```
1368 </div>
1369
1370 To make just one of the bounds exclusive, while keeping the other bound
1371 inclusive, we add a `<` on the left or on the right side of the range ':'
1372 operator. For example:
1373
1374 ```cpp
1375 typedef float ns__pos 0.0 < : ; // 0.0 < pos
1376 typedef float ns__neg : < 0.0 ; // neg < 0.0
1377 ```
1378
1379 It is valid to make both left and right side exclusive with `< : <` which is in
1380 fact identical to the exlusive range `<` operator:
1381
1382 ```cpp
1383 typedef float ns__epsilon 0.0 < : < 1.0; // 0.0 < eps < 1.0
1384 ```
1385
1386 It helps to think of the `:` as a placeholder of the value between the two
1387 bounds, which is easier to memorize than the shorthand forms of bounds from
1388 which the `:` is removed:
1389
1390 | Bounds | Validation Check | Shorthand |
1391 | ---------- | ---------------- | --------- |
1392 | 1 : | 1 <= x | 1 |
1393 | 1 : 10 | 1 <= x <= 10 | |
1394 | : 10 | x <= 10 | |
1395 | 1 < : < 10 | 1 < x < 10 | 1 < 10 |
1396 | 1 : < 10 | 1 <= x < 10 | |
1397 | : < 10 | x < 10 | < 10 |
1398 | 1 < : | 1 < x | 1 < |
1399 | 1 < : 10 | 1 < x <= 10 | |
1400
1401 Besides `float`, also `double` and `long double` values can be restricted. For
1402 example, consider a nonzero probability extended floating point precision type:
1403
1404 ```cpp
1405 #import "custom/long_double.h"
1406 typedef long double ns__probability "%16Lg" 0.0 < : 1.0;
1407 ```
1408
1409 Value range restrictions are validated by the parser for all inbound XML data.
1410 A type fault `SOAP_TYPE` will be thrown by the deserializer if the value is out
1411 of range.
1412
1413 Finally, if your system supports `__int128_t` then you can also use this 128
1414 bit integer type with a custom serializer:
1415
1416 ```cpp
1417 #import "custom/int128.h"
1418 ... use xsd__integer ...
1419 ```
1420
1421 Use the `xsd__integer` alias of `__int128_t`, which has a serializer. Do not
1422 use `__int128_t` directly, which is transient (not serializable).
1423
1424 To convert numeric values to a string, we use the auto-generated function for
1425 numeric type `T`:
1426
1427 ```cpp
1428 const char *soap_T2s(struct soap*, T val)
1429 ```
1430
1431 For numeric types `T`, the string returned is stored in an internal buffer of
1432 the current `soap` context, so you MUST copy it to keep it from being
1433 overwritten. For example, use `char *soap_strdup(struct soap*, const char*)`.
1434
1435 To convert a string to a numeric value, we use the auto-generated function
1436
1437 ```cpp
1438 int soap_s2T(struct soap*, const char *str, T *val)
1439 ```
1440
1441 where `T` is for example `int`, `LONG64`, `float`, `decimal` (the custom
1442 serializer name of `long double`) or `xsd__integer` (the custom serializer name
1443 of `__int128_t`). The function `soap_s2T` returns `SOAP_OK` on success or an
1444 error when the value is not numeric. For floating point types, "INF", "-INF"
1445 and "NaN" are valid strings to convert to numbers.
1446
1447 🔝 [Back to table of contents](#)
1448
1449 String types {#toxsd6}
1450 ------------
1451
1452 String types are mapped to the built-in `xsd:string` and `xsd:QName` XSD types.
1453
1454 The wide strings `wchar_t*` and `std::wstring` may contain Unicode that is
1455 preserved in the XML value space.
1456
1457 Strings `char*` and `std::string` can only contain extended Latin, but we can
1458 store UTF-8 content that is preserved in the XML value space when the `struct
1459 soap` context is initialized with the flag `SOAP_C_UTFSTRING`.
1460
1461 @warning Beware that many XML 1.0 parsers reject all control characters (those
1462 between `#x1` and `#x1F`) except for `#x9`, `#xA`, and `#xD`. With the
1463 newer XML 1.1 version parsers (including gSOAP) you should be fine.
1464
1465 The length of a string of a typedef-defined string type can be restricted:
1466
1467 ```cpp
1468 typedef std::string ns__password 6 : 16;
1469 ```
1470
1471 which maps to a simpleType restriction of `xsd:string` in the soapcpp2-generated
1472 schema:
1473
1474 <div class="alt">
1475 ```xml
1476 <simpleType name="password">
1477 <restriction base="xsd:string">
1478 <minLength value="6"/>
1479 <maxLength value="16"/>
1480 </restriction>
1481 </simpleType>
1482 ```
1483 </div>
1484
1485 String length restrictions are validated by the parser for inbound XML data.
1486 A value length fault `SOAP_LENGTH` will be thrown by the deserializer if the
1487 string is too long or too short.
1488
1489 In addition, an XSD regex pattern restriction can be associated with a string
1490 typedef:
1491
1492 ```cpp
1493 typedef std::string ns__password "([a-zA-Z]|[0-9]|-)+" 6 : 16;
1494 ```
1495
1496 which maps to a simpleType restriction of `xsd:string` in the soapcpp2-generated
1497 schema:
1498
1499 <div class="alt">
1500 ```xml
1501 <simpleType name="password">
1502 <restriction base="xsd:string">
1503 <pattern value="([a-zA-Z0-9]|-)+"/>
1504 <minLength value="6"/>
1505 <maxLength value="16"/>
1506 </restriction>
1507 </simpleType>
1508 ```
1509 </div>
1510
1511 Pattern restrictions are validated by the parser for inbound XML data only if
1512 the `soap::fsvalidate` and `soap::fwvalidate` callbacks are defined, see the
1513 [gSOAP user guide.](http://www.genivia.com/doc/soapdoc2.html)
1514
1515 Exclusive length bounds can be used with strings:
1516
1517 ```cpp
1518 typedef std::string ns__string255 : < 256; // same as 0 : 255
1519 ```
1520
1521 Fixed-size strings (`char[N]`) are rare occurrences in the wild, but apparently
1522 still used in some projects to store strings. To facilitate fixed-size string
1523 serialization, use soapcpp2 option `-b`. For example:
1524
1525 ```cpp
1526 typedef char ns__buffer[10]; // requires soapcpp2 option -b
1527 ```
1528
1529 which maps to a simpleType restriction of `xsd:string` in the soapcpp2-generated
1530 schema:
1531
1532 <div class="alt">
1533 ```xml
1534 <simpleType name="buffer">
1535 <restriction base="xsd:string">
1536 <maxLength value="9"/>
1537 </restriction>
1538 </simpleType>
1539 ```
1540 </div>
1541
1542 Note that fixed-size strings MUST contain NUL-terminated text and SHOULD NOT
1543 contain raw binary data. Also, the length limitation is more restrictive for
1544 UTF-8 content (enabled with the `SOAP_C_UTFSTRING`) that requires multibyte
1545 character encodings. As a consequence, UTF-8 content may be truncated to fit.
1546
1547 Note that raw binary data can be stored in a `xsd__base64Binary` or
1548 `xsd__hexBinary` structure, or transmitted as a MIME attachment.
1549
1550 The built-in `_QName` type is a regular C string type (`char*`) that maps to
1551 `xsd:QName` but has the added advantage that it holds normalized qualified names.
1552 There are actually two forms of normalized QName content, to ensure any QName
1553 is represented accurately and uniquely:
1554
1555 ```cpp
1556 "prefix:name"
1557 "\"URI\":name"
1558 ```
1559
1560 The first form of string is used when the prefix (and the binding URI) is
1561 defined in the namespace table and is bound to a URI (see the .nsmap file).
1562 The second form is used when the URI is not defined in the namespace table and
1563 therefore no prefix is available to bind and normalize the URI to.
1564
1565 A `_QName` string may contain a sequence of space-separated QName values, not
1566 just one, and all QName values are normalized to the format shown above.
1567
1568 To define a `std::string` base type for `xsd:QName`, we use a typedef:
1569
1570 ```cpp
1571 typedef std::string xsd__QName;
1572 ```
1573
1574 The `xsd__QName` string content is normalized, just as with the `_QName`
1575 normalization.
1576
1577 To serialize strings that contain literal XML content to be reproduced in the
1578 XML value space, use the built-in `_XML` string type, which is a regular C
1579 string type (`char*`) that maps to plain XML CDATA.
1580
1581 To define a `std::string` base type for literal XML content, use a typedef:
1582
1583 ```cpp
1584 typedef std::string XML;
1585 ```
1586
1587 Strings can hold any of the values of the XSD built-in primitive types. We can
1588 use a string typedef to declare the use of the string type as a XSD built-in
1589 type:
1590
1591 ```cpp
1592 typedef std::string xsd__token;
1593 ```
1594
1595 You MUST ensure that the string values we populate in this type conform to the
1596 XML standard, which in case of `xsd:token` is the lexical and value spaces of
1597 `xsd:token` are the sets of all strings after whitespace replacement of any
1598 occurrence of `#x9`, `#xA` , and `#xD` by `#x20` and collapsing.
1599
1600 As of version 2.8.49, the gSOAP parser will automatically collapse or replace
1601 the white space content when receiving data for XSD types that require white
1602 space collapsed or replaced. This normalization is applied to strings
1603 directly. The decision to collapse or replace is based on the `typedef` name
1604 corresponding to the built-in string-based XSD type.
1605
1606 To copy `char*` or `wchar_t*` strings with a context that manages the allocated
1607 memory, use functions
1608
1609 ```cpp
1610 char *soap_strdup(struct soap*, const char*)
1611 wchar_t *soap_wstrdup(struct soap*, const wchar_t*)
1612 ```
1613
1614 To convert a wide string to a UTF-8 encoded string, use function
1615
1616 ```cpp
1617 const char* SOAP_FMAC2 soap_wchar2s(struct soap*, const wchar_t *s)
1618 ```
1619
1620 The function allocates and returns a string, with its memory being managed by
1621 the context.
1622
1623 To convert a UTF-8 encoded string to a wide string, use function
1624
1625 ```cpp
1626 int soap_s2wchar(struct soap*, const char *from, wchar_t **to, long minlen, long maxlen)
1627 ```
1628
1629 where `to` is set to point to an allocated `wchar_t*` string. Pass `-1` for
1630 `minlen` and `maxlen` to ignore length constraints on the target string. The
1631 function returns `SOAP_OK` or an error when the length constraints are not met.
1632
1633 🔝 [Back to table of contents](#)
1634
1635 Date and time types {#toxsd7}
1636 -------------------
1637
1638 The C/C++ `time_t` type is mapped to the built-in `xsd:dateTime` XSD type that
1639 represents a date and time within a time zone (typically UTC).
1640
1641 The XML value space contains ISO 8601 Gregorian time instances of the form
1642 `[-]CCYY-MM-DDThh:mm:ss.sss[Z|(+|-)hh:mm]`, where `Z` is the UTC time zone
1643 or a time zone offset `(+|-)hh:mm]` from UTC is used.
1644
1645 A `time_t` value is considered and represented in UTC by the serializer.
1646
1647 Because the `time_t` value range is restricted to dates after 01/01/1970 and
1648 before 2038 assuming `time_t` is a `long` 32 bit, care must be taken to ensure
1649 the range of `xsd:dateTime` values in XML exchanges do not exceed the `time_t`
1650 range.
1651
1652 This restriction does not hold for `struct tm` (`<time.h>`), which we can use
1653 to store and exchange a date and time in UTC without date range restrictions.
1654 The serializer uses the `struct tm` members directly for the XML value space of
1655 `xsd:dateTime`:
1656
1657 ```cpp
1658 struct tm
1659 {
1660 int tm_sec; // seconds (0 - 60)
1661 int tm_min; // minutes (0 - 59)
1662 int tm_hour; // hours (0 - 23)
1663 int tm_mday; // day of month (1 - 31)
1664 int tm_mon; // month of year (0 - 11)
1665 int tm_year; // year - 1900
1666 int tm_wday; // day of week (Sunday = 0) (NOT USED)
1667 int tm_yday; // day of year (0 - 365) (NOT USED)
1668 int tm_isdst; // is summer time in effect?
1669 char* tm_zone; // abbreviation of timezone (NOT USED)
1670 };
1671 ```
1672
1673 You will lose the day of the week information. It is always Sunday
1674 (`tm_wday=0`) and the day of the year is not set either. The time zone is UTC.
1675
1676 This `struct tm` type is mapped to the built-in `xsd:dateTime` XSD type and
1677 serialized with the custom serializer `custom/struct_tm.h` that declares a
1678 `xsd__dateTime` type:
1679
1680 ```cpp
1681 #import "custom/struct_tm.h" // import typedef struct tm xsd__dateTime;
1682 ... use xsd__dateTime ...
1683 ```
1684
1685 Compile and link your code with `custom/struct_tm.c`.
1686
1687 The `struct timeval` (`<sys/time.h>`) type is mapped to the built-in
1688 `xsd:dateTime` XSD type and serialized with the custom serializer
1689 `custom/struct_timeval.h` that declares a `xsd__dateTime` type:
1690
1691 ```cpp
1692 #import "custom/struct_timeval.h" // import typedef struct timeval xsd__dateTime;
1693 ... use xsd__dateTime ...
1694 ```
1695
1696 Compile and link your code with `custom/struct_timeval.c`.
1697
1698 Note that the same value range restrictions apply to `struct timeval` as they
1699 apply to `time_t`. The added benefit of `struct timeval` is the addition of
1700 a microsecond-precise clock:
1701
1702 ```cpp
1703 struct timeval
1704 {
1705 time_t tv_sec; // seconds since Jan. 1, 1970
1706 suseconds_t tv_usec; // and microseconds
1707 };
1708 ```
1709
1710 A C++11 `std::chrono::system_clock::time_point` type is mapped to the built-in
1711 `xsd:dateTime` XSD type and serialized with the custom serializer
1712 `custom/chrono_time_point.h` that declares a `xsd__dateTime` type:
1713
1714 ```cpp
1715 #import "custom/chrono_time_point.h" // import typedef std::chrono::system_clock::time_point xsd__dateTime;
1716 ... use xsd__dateTime ...
1717 ```
1718
1719 Compile and link your code with `custom/chrono_time_point.cpp`.
1720
1721 The `struct tm` type is mapped to the built-in `xsd:date` XSD type and serialized
1722 with the custom serializer `custom/struct_tm_date.h` that declares a
1723 `xsd__date` type:
1724
1725 ```cpp
1726 #import "custom/struct_tm_date.h" // import typedef struct tm xsd__date;
1727 ... use xsd__date ...
1728 ```
1729
1730 Compile and link your code with `custom/struct_tm_date.c`.
1731
1732 The XML value space of `xsd:date` are Gregorian calendar dates of the form
1733 `[-]CCYY-MM-DD[Z|(+|-)hh:mm]` with a time zone.
1734
1735 The serializer ignores the time part and the deserializer only populates the
1736 date part of the struct, setting the time to 00:00:00. There is no unreasonable
1737 limit on the date range because the year field is stored as an integer (`int`).
1738
1739 An `unsigned long long` (`ULONG64` or `uint64_t`) type that contains a 24 hour
1740 time in microseconds UTC is mapped to the built-in `xsd:time` XSD type and
1741 serialized with the custom serializer `custom/long_time.h` that declares a
1742 `xsd__time` type:
1743
1744 ```cpp
1745 #import "custom/long_time.h" // import typedef unsigned long long xsd__time;
1746 ... use xsd__time ...
1747 ```
1748
1749 Compile and link your code with `custom/long_time.c`.
1750
1751 This type represents `00:00:00.000000` to `23:59:59.999999`, from 0 to an
1752 upper bound of 86,399,999,999. A microsecond resolution means that a 1 second
1753 increment requires an increment of 1,000,000 in the integer value.
1754
1755 The XML value space of `xsd:time` are points in time recurring each day of the
1756 form `hh:mm:ss.sss[Z|(+|-)hh:mm]`, where `Z` is the UTC time zone or a time
1757 zone offset from UTC is used. The `xsd__time` value is always considered and
1758 represented in UTC by the serializer.
1759
1760 To convert date and/or time values to a string, we use the auto-generated
1761 function for type `T`:
1762
1763 ```cpp
1764 const char *soap_T2s(struct soap*, T val)
1765 ```
1766
1767 For date and time types `T`, the string returned is stored in an internal
1768 buffer of the current `soap` context, so you MUST copy it to keep it from being
1769 overwritten. For example, use `char *soap_strdup(struct soap*, const char*)`.
1770
1771 To convert a string to a date/time value, we use the auto-generated function
1772
1773 ```cpp
1774 int soap_s2T(struct soap*, const char *str, T *val)
1775 ```
1776
1777 where `T` is for example `dateTime` (for `time_t`), `xsd__dateTime` (for
1778 `struct tm`, `struct timeval`, or `std::chrono::system_clock::time_point`).
1779 The function `soap_s2T` returns `SOAP_OK` on success or an error when the value
1780 is not a date/time.
1781
1782 🔝 [Back to table of contents](#)
1783
1784 Time duration types {#toxsd8}
1785 -------------------
1786
1787 The XML value space of `xsd:duration` are values of the form `PnYnMnDTnHnMnS`
1788 where the capital letters are delimiters. Delimiters may be omitted when the
1789 corresponding member is not used.
1790
1791 A `long long` (`LONG64` or `int64_t`) type that contains a duration (time
1792 lapse) in milliseconds is mapped to the built-in `xsd:duration` XSD type and
1793 serialized with the custom serializer `custom/duration.h` that declares a
1794 `xsd__duration` type:
1795
1796 ```cpp
1797 #import "custom/duration.h" // import typedef long long xsd__duration;
1798 ... use xsd__duration ...
1799 ```
1800
1801 Compile and link your code with `custom/duration.c`.
1802
1803 The duration type `xsd__duration` can represent 106,751,991,167 days forward
1804 and backward with millisecond precision.
1805
1806 Durations that exceed a month are always output in days, rather than months to
1807 avoid days-per-month conversion inacurracies.
1808
1809 Durations that are received in years and months instead of total number of days
1810 from a reference point are not well defined, since there is no accepted
1811 reference time point (it may or may not be the current time). The decoder
1812 simple assumes that there are 30 days per month. For example, conversion of
1813 "P4M" gives 120 days. Therefore, the durations "P4M" and "P120D" are assumed
1814 to be identical, which is not necessarily true depending on the reference point
1815 in time.
1816
1817 Rescaling of the duration value by may be needed when adding the duration value
1818 to a `time_t` value, because `time_t` may or may not have a seconds resolution,
1819 depending on the platform and possible changes to `time_t`.
1820
1821 Rescaling is done automatically when you add a C++11 `std::chrono::nanoseconds`
1822 value to a `std::chrono::system_clock::time_point` value. To use
1823 `std::chrono::nanoseconds` as `xsd:duration`:
1824
1825 ```cpp
1826 #import "custom/chrono_duration.h" // import typedef std::chrono::duration xsd__duration;
1827 ... use xsd__duration ...
1828 ```
1829
1830 Compile and link your code with `custom/chrono_duration.cpp`.
1831
1832 This type can represent 384,307,168 days (2^63 nanoseconds) forwards and
1833 backwards in time in increments of 1 ns (1/1000000000 second).
1834
1835 The same observations with respect to receiving durations in years and months
1836 apply to this serializer's decoder.
1837
1838 To convert duration values to a string, we use the auto-generated function
1839
1840 ```cpp
1841 const char *soap_xsd__duration2s(struct soap*, xsd__duration val)
1842 ```
1843
1844 The string returned is stored in an internal buffer, so you MUST copy it to
1845 keep it from being overwritten, Use `soap_strdup(struct soap*, const char*)`
1846 for example to copy this string.
1847
1848 To convert a string to a duration value, we use the auto-generated function
1849
1850 ```cpp
1851 int soap_s2xsd__dateTime(struct soap*, const char *str, xsd__dateTime *val)
1852 ```
1853
1854 The function returns `SOAP_OK` on success or an error when the value is not a
1855 duration.
1856
1857 🔝 [Back to table of contents](#)
1858
1859 Classes and structs {#toxsd9}
1860 -------------------
1861
1862 Classes and structs are mapped to XSD complexTypes. The XML value space
1863 consists of XML elements with attributes and subelements, possibly constrained
1864 by XML schema validation rules that enforce element and attribute occurrence
1865 contraints, numerical value range constraints, and string length and pattern
1866 constraints.
1867
1868 Classes that are declared with the gSOAP tools are limited to single
1869 inheritence only. Structs cannot be inherited.
1870
1871 The class and struct name is bound to an XML namespace by means of the prefix
1872 naming convention or by using [colon notation](#toxsd1):
1873
1874 ```cpp
1875 //gsoap ns schema namespace: urn:types
1876 class ns__record
1877 {
1878 public:
1879 std::string name;
1880 uint64_t SSN;
1881 ns__record *spouse;
1882 ns__record();
1883 ~ns__record();
1884 protected:
1885 struct soap *soap;
1886 };
1887 ```
1888
1889 In the example above, we also added a context pointer to the `struct soap` that
1890 manages this instance. It is set when the instance is created in the engine's
1891 context, for example when deserialized and populated by the engine.
1892
1893 The class maps to a complexType in the soapcpp2-generated schema:
1894
1895 <div class="alt">
1896 ```xml
1897 <complexType name="record">
1898 <sequence>
1899 <element name="name" type="xsd:string" minOccurs="1" maxOccurs="1"/>
1900 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
1901 <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1" nillable="true"/>
1902 </sequence>
1903 </complexType>
1904 ```
1905 </div>
1906
1907 🔝 [Back to table of contents](#)
1908
1909 ### Serializable versus transient types and data members {#toxsd9-1}
1910
1911 Public data members of a class or struct are serialized. Private and protected
1912 members are transient and not serializable.
1913
1914 Also `const` and `static` members are not serializable, with the exception of
1915 `const char*` and `const wchar_t*`. Types and specific class/struct members
1916 can also be made transient with the `extern` qualifier:
1917
1918 ```cpp
1919 extern class std::ostream; // declare 'std::ostream' transient
1920 class ns__record
1921 {
1922 public:
1923 extern int num; // not serialized
1924 std::ostream out; // not serialized
1925 static const int MAX = 1024; // not serialized
1926 };
1927 ```
1928
1929 By declaring `std::ostream` transient with `extern` you can use this type
1930 wherever you need it without soapcpp2 complaining that this class is not
1931 defined.
1932
1933 🔝 [Back to table of contents](#)
1934
1935 ### Volatile classes and structs {#toxsd9-2}
1936
1937 Classes and structs can be declared `volatile` with the gSOAP tools. This means
1938 that they are already declared elsewhere in your project's source code and you
1939 do not want soapcpp2 to generate code with a second declaration of these types.
1940
1941 For example, `struct tm` is declared in `<time.h>`. You can make it serializable
1942 and include a partial list of data members that you want to serialize:
1943
1944 ```cpp
1945 volatile struct tm
1946 {
1947 int tm_sec; // seconds (0 - 60)
1948 int tm_min; // minutes (0 - 59)
1949 int tm_hour; // hours (0 - 23)
1950 int tm_mday; // day of month (1 - 31)
1951 int tm_mon; // month of year (0 - 11)
1952 int tm_year; // year - 1900
1953 };
1954 ```
1955
1956 You can declare classes and structs `volatile` for any such types you want to
1957 serialize by only providing the public data members you want to serialize.
1958
1959 In addition, [colon notation](#toxsd2) is a simple and effective way to bind an
1960 existing class or struct to a schema. For example, you can change the `tm` name
1961 as follows without affecting the code that uses `struct tm` generated by
1962 soapcpp2:
1963
1964 ```cpp
1965 volatile struct ns:tm { ... }
1966 ```
1967
1968 This struct maps to a complexType in the soapcpp2-generated schema:
1969
1970 <div class="alt">
1971 ```xml
1972 <complexType name="tm">
1973 <sequence>
1974 <element name="tm-sec" type="xsd:int" minOccurs="1" maxOccurs="1"/>
1975 <element name="tm-min" type="xsd:int" minOccurs="1" maxOccurs="1"/>
1976 <element name="tm-hour" type="xsd:int" minOccurs="1" maxOccurs="1"/>
1977 <element name="tm-mday" type="xsd:int" minOccurs="1" maxOccurs="1"/>
1978 <element name="tm-mon" type="xsd:int" minOccurs="1" maxOccurs="1"/>
1979 <element name="tm-year" type="xsd:int" minOccurs="1" maxOccurs="1"/>
1980 </sequence>
1981 </complexType>
1982 ```
1983 </div>
1984
1985 🔝 [Back to table of contents](#)
1986
1987 ### Mutable classes and structs {#toxsd9-3}
1988
1989 Classes and structs can be declared `mutable` with the gSOAP tools. This means
1990 that their definition can be spread out over the source code. This promotes the
1991 concept of a class or struct as a *row of named values*, also known as a *named
1992 tuple*, that can be extended at compile time in your source code with additional
1993 members. Because these types differ from the traditional object-oriented
1994 principles and design concepts of classes and objects, constructors and
1995 destructors cannot be defined (also because we cannot guarantee merging these
1996 into one such that all members will be initialized). A default constructor,
1997 copy constructor, assignment operation, and destructor will be assigned
1998 automatically by soapcpp2.
1999
2000 ```cpp
2001 mutable struct ns__tuple
2002 {
2003 @std::string id;
2004 };
2005
2006 mutable struct ns__tuple
2007 {
2008 std::string name;
2009 std::string value;
2010 };
2011 ```
2012
2013 The members are collected into one definition generated by soapcpp2. Members
2014 may be repeated from one definition to another, but only if their associated
2015 types are identical. So, for example, a third extension with a `value` member
2016 with a different type fails:
2017
2018 ```cpp
2019 mutable struct ns__tuple
2020 {
2021 float value; // BAD: value is already declared std::string
2022 };
2023 ```
2024
2025 The `mutable` concept has proven to be very useful when declaring and
2026 collecting SOAP Headers for multiple services, which are collected into one
2027 `struct SOAP_ENV__Header` by the soapcpp2 tool.
2028
2029 🔝 [Back to table of contents](#)
2030
2031 ### Default and fixed member values {#toxsd9-4}
2032
2033 Class and struct data members in C and C++ may be declared with an optional
2034 default initialization value that is provided "inline" with the declaration of
2035 the member:
2036
2037 ```cpp
2038 class ns__record
2039 {
2040 public:
2041 std::string name = "Joe";
2042 ...
2043 };
2044 ```
2045
2046 Alternatively, use C++11 default initialization syntax:
2047
2048 ```cpp
2049 class ns__record
2050 {
2051 public:
2052 std::string name { "Joe" };
2053 ...
2054 };
2055 ```
2056
2057 These initializations are made by the default constructor that is added by
2058 soapcpp2 to each class and struct (in C++ only). A constructor is only added
2059 when a default constructor is not already defined with the class declaration.
2060
2061 You can explicitly (re)initialize an object with these initial values by using
2062 the soapcpp2 auto-generated functions:
2063
2064 - `void T::soap_default(struct soap*)` for `class T` (C++ only)
2065 - `void soap_default_T(struct soap*, T*)` for `struct T` (C and C++).
2066
2067 Default value initializations can be provided for members that have primitive
2068 types (`bool`, `enum`, `time_t`, numeric and string types).
2069
2070 Default value initializations of pointer members is permitted, but the effect
2071 is different. To conform to XML schema validation, an attribute member that is
2072 a pointer to a primitive type will be assigned the default value when parsed
2073 from XML. An element member that is a pointer to a primitive type will be
2074 assigned when the element is empty when parsed from XML.
2075
2076 As of gSOAP 2.8.48 and greater, a fixed value can be assigned with a `==`. A
2077 fixed value is also verified by the parser's validator.
2078
2079 Default and fixed values for members with or without pointers are best
2080 explained with the following two example fragments.
2081
2082 A record class (can be a struct in C) with default values for attributes and
2083 elements is declared as follows:
2084
2085 ```cpp
2086 class ns__record_with_default
2087 {
2088 public:
2089 @std::string a = "A"; // optional XML attribute with default value "A"
2090 @std::string b 1 = "B"; // required XML attribute with default value "B"
2091 @std::string *c = "C"; // optional XML attribute with default value "C"
2092 std::string d 0 = "D"; // optional XML element with default value "D"
2093 std::string e = "E"; // required XML element with default value "E"
2094 std::string *f = "F"; // optional XML element with default value "F"
2095 ...
2096 };
2097 ```
2098
2099 Note that attributes are optional unless marked as required with the occurrence
2100 constraint `1`. Elements are required unless the member type is a pointer or
2101 if the member is marked optional with occurrence constraint `0`.
2102
2103 Instead of default values, fixed values indicate that the attribute or element
2104 must contain that value, and only that value, when provided in XML. A fixed
2105 value is specified with a `==`.
2106
2107 A record class (can be a struct in C) with fixed values for attributes and
2108 elements is declared as follows:
2109
2110 ```cpp
2111 class ns__record_with_fixed
2112 {
2113 public:
2114 @std::string g == "G"; // optional XML attribute with fixed value "G"
2115 @std::string h 1 == "H"; // required XML attribute with fixed value "H"
2116 @std::string *i == "I"; // optional XML attribute with fixed value "I"
2117 std::string j 0 == "J"; // optional XML element with fixed value "J"
2118 std::string k == "K"; // required XML element with fixed value "K"
2119 std::string *l == "L"; // optional XML element with fixed value "L"
2120 ...
2121 };
2122 ```
2123
2124 The XML schema validation rules for the two example classes above are as
2125 follows:
2126
2127 Member | Notes
2128 ------ | ---------------------------------------------------------------------
2129 `a` | attribute may appear once; if it does not appear its value is "A", otherwise its value is that given (also note: instantiating `ns__record_with_default` assigns the default value "A")
2130 `b` | has no effect when parsing XML (but note: instantiating `ns__record_with_default` assigns the default value "B")
2131 `c` | attribute may appear once; if it does not appear its value is "C", otherwise its value is that given (also note: instantiating `ns__record_with_default` assigns NULL)
2132 `d` | element may appear once; if it does not appear or if it is empty, its value is "D"; otherwise its value is that given (also note: instantiating `ns__record_with_default` assigns the default value "D")
2133 `e` | has no effect when parsing XML (but note: instantiating `ns__record_with_default` assigns the default value "E")
2134 `f` | element may appear once; if it does not appear it is not provided; if it does appear and it is empty, its value is "F"; otherwise its value is that given (also note: instantiating `ns__record_with_default` assigns NULL)
2135 `g` | attribute may appear once; if it does not appear its value is "G", if it does not appear its value is "G" (also note: instantiating `ns__record_with_fixed` assigns the fixed value "G")
2136 `h` | attribute must appear once, its value must be "H" (also note: instantiating `ns__record_with_fixed` assigns the fixed value "H")
2137 `i` | attribute may appear once; if it does not appear its value is "I", if it does not appear its value is "I" (also note: instantiating `ns__record_with_fixed` assigns NULL)
2138 `j` | element may appear once, if it does not appear it is not provided; if it does appear and it is empty, its value is "J"; if it does appear and it is not empty, its value must be "J" (also note: instantiating `ns__record_with_fixed` assigns the fixed value "J")
2139 `k` | element must appear once, its value must be "K" (also note: instantiating `ns__record_with_fixed` assigns the fixed value "K")
2140 `l` | element may appear once, if it does not appear it is not provided; if it does appear and it is empty, its value is "J"; if it does appear and it is not empty, its value must be "J" (also note: instantiating `ns__record_with_fixed` assigns NULL)
2141
2142 @see Section [operations on classes and structs](#toxsd9-13).
2143
2144 🔝 [Back to table of contents](#)
2145
2146 ### Attribute members and backtick XML tags {#toxsd9-5}
2147
2148 Class and struct data members are declared as XML attributes by annotating
2149 their type with a `@` qualifier:
2150
2151 ```cpp
2152 class ns__record
2153 {
2154 public:
2155 @std::string name; // required (non-pointer means required)
2156 @uint64_t SSN; // required (non-pointer means required)
2157 ns__record *spouse; // optional (pointer means minOccurs=0)
2158 };
2159 ```
2160
2161 This class maps to a complexType in the soapcpp2-generated schema:
2162
2163 <div class="alt">
2164 ```xml
2165 <complexType name="record">
2166 <sequence>
2167 <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1" nillable="true"/>
2168 </sequence>
2169 <attribute name="name" type="xsd:string" use="required"/>
2170 <attribute name="SSN" type="xsd:unsignedLong" use="required"/>
2171 </complexType>
2172 ```
2173 </div>
2174
2175 An example XML instance of `ns__record` is:
2176
2177 <div class="alt">
2178 ```xml
2179 <ns:record xmlns:ns="urn:types" name="Joe" SSN="1234567890">
2180 <spouse name="Jane" SSN="1987654320">
2181 </spouse>
2182 </ns:record>
2183 ```
2184 </div>
2185
2186 Attribute data members are restricted to primitive types (`bool`, `enum`,
2187 `time_t`, numeric and string types), `xsd__hexBinary`, `xsd__base64Binary`, and
2188 custom serializers, such as `xsd__dateTime`. Custom serializers for types that
2189 may be used as attributes MUST define `soap_s2T` and `soap_T2s` functions that
2190 convert values of type `T` to strings and back.
2191
2192 Attribute data members can be pointers and smart pointers to these types, which
2193 permits attributes to be optional.
2194
2195 The XML tag name of a class/struct member is the name of the member with the
2196 usual XML tag translation, see [colon notation](#toxsd2).
2197
2198 To override the standard translation of identifier names to XML tag names of
2199 attributes and elements, add the XML tag name in backticks (requires gSOAP
2200 2.8.30 and later versions):
2201
2202 ```cpp
2203 class ns__record
2204 {
2205 public:
2206 @std::string name `full-name`;
2207 @uint64_t SSN `tax-id`;
2208 ns__record *spouse `married-to`;
2209 };
2210 ```
2211
2212 This class maps to a complexType in the soapcpp2-generated schema:
2213
2214 <div class="alt">
2215 ```xml
2216 <complexType name="record">
2217 <sequence>
2218 <element name="married-to" type="ns:record" minOccurs="0" maxOccurs="1"/>
2219 </sequence>
2220 <attribute name="full-name" type="xsd:string" use="required"/>
2221 <attribute name="tax-id" type="xsd:unsignedLong" use="required"/>
2222 </complexType>
2223 ```
2224 </div>
2225
2226 An example XML instance of `ns__record` is:
2227
2228 <div class="alt">
2229 ```xml
2230 <ns:record xmlns:ns="urn:types" full-name="Joe" tax-id="1234567890">
2231 <married-to full-name="Jane" tax-id="1987654320">
2232 </married-to>
2233 </ns:record>
2234 ```
2235 </div>
2236
2237 A backtick XML tag name may contain any non-empty sequence of ASCII and UTF-8
2238 characters except white space and the backtick character. A backtick tag can
2239 be combined with member constraints and default member initializers:
2240
2241 @uint64_t SSN `tax-id` 0:1 = 999;
2242
2243 🔝 [Back to table of contents](#)
2244
2245 ### Qualified and unqualified members {#toxsd9-6}
2246
2247 Class, struct, and union data members are mapped to namespace qualified or
2248 unqualified tag names of local elements and attributes. If a data member has
2249 no prefix then the default form of qualification is applied based on the
2250 element/attribute form that is declared with the schema of the class, struct,
2251 or union type. If the member name has a namespace prefix by colon notation,
2252 then the prefix overrules the default (un)qualified form. Therefore,
2253 [colon notation](#toxsd2) is an effective mechanism to control qualification of
2254 tag names of individual members of classes, structs, and unions.
2255
2256 The XML schema elementFormDefault and attributeFormDefault declarations control
2257 the tag name qualification of local elements and attributes, respectively.
2258
2259 - "unqualified" indicates that local elements/attributes are not qualified with
2260 the namespace prefix.
2261
2262 - "qualified" indicates that local elements/attributes must be qualified with
2263 the namespace prefix.
2264
2265 Individual schema declarations of local elements and attributes may overrule
2266 this by using the form declaration in a schema and by using colon notation to
2267 add namespace prefixes to class, struct, and union members in the header file
2268 for soapcpp2.
2269
2270 Consider for example an `ns__record` class in the `ns` namespace in which local
2271 elements are qualified and local attributes are unqualified by default:
2272
2273 ```cpp
2274 //gsoap ns schema namespace: urn:types
2275 //gsoap ns schema elementForm: qualified
2276 //gsoap ns schema attributeForm: unqualified
2277 class ns__record
2278 {
2279 public:
2280 @std::string name;
2281 @uint64_t SSN;
2282 ns__record *spouse;
2283 };
2284 ```
2285
2286 This class maps to a complexType in the soapcpp2-generated schema with
2287 targetNamespace "urn:types", elementFormDefault qualified and
2288 attributeFormDefault unqualified:
2289
2290 <div class="alt">
2291 ```xml
2292 <schema targetNamespace="urn:types"
2293 ...
2294 elementFormDefault="qualified"
2295 attributeFormDefault="unqualified"
2296 ... >
2297 <complexType name="record">
2298 <sequence>
2299 <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1"/>
2300 </sequence>
2301 <attribute name="name" type="xsd:string" use="required"/>
2302 <attribute name="SSN" type="xsd:unsignedLong" use="required"/>
2303 </complexType>
2304 </schema>
2305 ```
2306 </div>
2307
2308 An example XML instance of `ns__record` is:
2309
2310 <div class="alt">
2311 ```xml
2312 <ns:record xmlns:ns="urn:types" name="Joe" SSN="1234567890">
2313 <ns:spouse> name="Jane" SSN="1987654320">
2314 </ns:spouse>
2315 </ns:record>
2316 ```
2317 </div>
2318
2319 Note that the root element `<ns:record>` is qualified because it is a root element
2320 of the schema with target namespace "urn:types". Its local element `<ns:spouse>`
2321 is namespace qualified because the elementFormDefault of local elements is
2322 qualified. Attributes are unqualified.
2323
2324 The default namespace (un)qualification of local elements and attributes can be
2325 overruled by adding a prefix to the member name by using colon notation:
2326
2327 ```cpp
2328 //gsoap ns schema namespace: urn:types
2329 //gsoap ns schema elementForm: qualified
2330 //gsoap ns schema attributeForm: unqualified
2331 class ns__record
2332 {
2333 public:
2334 @std::string ns:name; // 'ns:' qualified
2335 @uint64_t SSN;
2336 ns__record *:spouse; // ':' unqualified (empty prefix)
2337 };
2338 ```
2339
2340 The colon notation for member `ns:name` forces qualification of its attribute
2341 tag in XML. The colon notation for member `:spouse` removes qualification from
2342 its local element tag:
2343
2344 <div class="alt">
2345 ```xml
2346 <schema targetNamespace="urn:types"
2347 ...
2348 elementFormDefault="unqualified"
2349 attributeFormDefault="unqualified"
2350 ... >
2351 <complexType name="record">
2352 <sequence>
2353 <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1" form="unqualified"/>
2354 </sequence>
2355 <attribute name="name" type="xsd:string" use="required" form="qualified"/>
2356 <attribute name="SSN" type="xsd:unsignedLong" use="required"/>
2357 </complexType>
2358 </schema>
2359 ```
2360 </div>
2361
2362 XML instances of `ns__record` have unqualified spouse elements and qualified
2363 ns:name attributes:
2364
2365 <div class="alt">
2366 ```xml
2367 <ns:record xmlns:ns="urn:types" ns:name="Joe" SSN="1234567890">
2368 <spouse> ns:name="Jane" SSN="1987654320">
2369 </spouse>
2370 </ns:record>
2371 ```
2372 </div>
2373
2374 Note that data members can also be prefixed using the `prefix__name`
2375 convention. However, this has a different effect by referring to global (root)
2376 elements and attributes, see [document root element definitions](#toxsd9-7).
2377
2378 [Backtick tag names](#toxsd9-5) can be used in place of the member name
2379 annotations and will achieve the same effect as described when these tag names
2380 are (un)qualified (requires gSOAP 2.8.30 and later versions).
2381
2382 @note You must declare a target namespace with a `//gsoap ns schema namespace:`
2383 directive to enable the `elementForm` and `attributeForm` directives in order
2384 to generate valid schemas with soapcpp2. See [directives](#directives) for
2385 more details.
2386
2387 🔝 [Back to table of contents](#)
2388
2389 ### Defining document root elements {#toxsd9-7}
2390
2391 To define and reference XML document root elements we use type names that start
2392 with an underscore:
2393
2394 ```cpp
2395 class _ns__record
2396 ```
2397
2398 Alternatively, we can use a typedef to define a document root element with a
2399 given type:
2400
2401 ```cpp
2402 typedef ns__record _ns__record;
2403 ```
2404
2405 This typedef maps to a global root element that is added to the
2406 soapcpp2-generated schema:
2407
2408 <div class="alt">
2409 ```xml
2410 <element name="record" type="ns:record"/>
2411 ```
2412 </div>
2413
2414 An example XML instance of `_ns__record` is:
2415
2416 <div class="alt">
2417 ```xml
2418 <ns:record xmlns:ns="urn:types">
2419 <name>Joe</name>
2420 <SSN>1234567890</SSN>
2421 <spouse>
2422 <name>Jane</name>
2423 <SSN>1987654320</SSN>
2424 </spouse>
2425 </ns:record>
2426 ```
2427 </div>
2428
2429 Global-level element/attribute definitions are also referenced and/or added to
2430 the generated schema when serializable data members reference these by their
2431 qualified name:
2432
2433 ```cpp
2434 typedef std::string _ns__name 1 : 100;
2435 class _ns__record
2436 {
2437 public:
2438 @_QName xsi__type; // built-in XSD attribute xsi:type
2439 _ns__name ns__name; // ref to global ns:name element
2440 uint64_t SSN;
2441 _ns__record *spouse;
2442 };
2443 ```
2444
2445 These types map to the following comonents in the soapcpp2-generated schema:
2446
2447 <div class="alt">
2448 ```xml
2449 <simpleType name="name">
2450 <restriction base="xsd:string">
2451 <minLength value="1"/>
2452 <maxLength value="100"/>
2453 </restriction>
2454 </simpleType>
2455 <element name="name" type="ns:name"/>
2456 <complexType name="record">
2457 <sequence>
2458 <element ref="ns:name" minOccurs="1" maxOccurs="1"/>
2459 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
2460 <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1"/>
2461 </sequence>
2462 <attribute ref="xsi:type" use="optional"/>
2463 </complexType>
2464 <element name="record" type="ns:record"/>
2465 ```
2466 </div>
2467
2468 Use only use qualified member names when their types match the global-level
2469 element types that they refer to. For example:
2470
2471 ```cpp
2472 typedef std::string _ns__name; // global element ns:name of type xsd:string
2473 class _ns__record
2474 {
2475 public:
2476 int ns__name; // BAD: global element ns:name is NOT type int
2477 _ns__record ns__record; // OK: ns:record is a global-level root element
2478 ...
2479 };
2480 ```
2481
2482 Therefore, we recommend to use qualified member names only when necessary to
2483 refer to standard XSD elements and attributes, such as `xsi__type`, and
2484 `xsd__lang`.
2485
2486 By contrast, colon notation has the desired effect to (un)qualify local tag
2487 names by overruling the default element/attribute namespace qualification, see
2488 [qualified and unqualified members](#toxsd9-6).
2489
2490 As an alternative to prefixing member names, use the backtick tag (requires
2491 gSOAP 2.8.30 and later versions):
2492
2493 ```cpp
2494 typedef std::string _ns__name 1 : 100;
2495 class _ns__record
2496 {
2497 public:
2498 @_QName t `xsi:type`; // built-in XSD attribute xsi:type
2499 _ns__name s `ns:name`; // ref to global ns:name element
2500 uint64_t SSN;
2501 _ns__record *spouse;
2502 };
2503 ```
2504
2505 🔝 [Back to table of contents](#)
2506
2507 ### (Smart) pointer members and their occurrence constraints {#toxsd9-8}
2508
2509 A public pointer-typed data member is serialized by following its (smart)
2510 pointer(s) to the value pointed to. To serialize pointers to dynamic arrays of
2511 data, please see the next section on
2512 [container and array members and their occurrence constraints](#toxsd9-9).
2513
2514 Pointers that are NULL and smart pointers that are empty are serialized to
2515 produce omitted element and attribute values, unless an element is required
2516 and is nillable (struct/class members marked with `nullptr`) in which case the
2517 element is rendered as an empty element with `xsi:nil="true"`.
2518
2519 To control the occurrence requirements of pointer-based data members,
2520 occurrence constraints are associated with data members in the form of a range
2521 `minOccurs : maxOccurs`. For non-repeatable (meaning, not a container or array)
2522 data members, there are only three reasonable occurrence constraints:
2523
2524 - `0:0` means that this element or attribute is prohibited.
2525 - `0:1` means that this element or attribute is optional.
2526 - `1:1` means that this element or attribute is required.
2527
2528 Pointer-based data members have a default `0:1` occurrence constraint, making
2529 them optional, and their XML schema local element/attribute definition is
2530 marked as nillable. Non-pointer data members have a default `1:1` occurence
2531 constraint, making them required.
2532
2533 A `nullptr` occurrence constraint may be applicable to required elements that
2534 are nillable pointer types, thus `nullptr 1:1`. This indicates that the
2535 element is nillable (can be `NULL` or `nullptr`). A pointer data member that
2536 is explicitly marked as required and nillable with `nullptr 1:1` will be
2537 serialized as an element with an `xsi:nil` attribute, thus effectively
2538 revealing the NULL property of its value.
2539
2540 A non-pointer data member that is explicitly marked as optional with `0:1` will
2541 be set to its default value when no XML value is presented to the deserializer.
2542 A default value can be assigned to a data member that has a primitive type or
2543 is a (smart) pointer to primitive type.
2544
2545 Consider for example:
2546
2547 ```cpp
2548 class ns__record
2549 {
2550 public:
2551 std::shared_ptr<std::string> name; // optional (pointer means minOccurs=0)
2552 uint64_t SSN 0:1 = 999; // force optional with default 999
2553 ns__record *spouse nullptr 1:1; // force required and nillabe when absent
2554 };
2555 ```
2556
2557 This class maps to a complexType in the soapcpp2-generated schema:
2558
2559 <div class="alt">
2560 ```xml
2561 <complexType name="record">
2562 <sequence>
2563 <element name="name" type="xsd:string" minOccurs="0" maxOccurs="1" nillable="true"/>
2564 <element name="SSN" type="xsd:unsignedLong" minOccurs="0" maxOccurs="1" default="999"/>
2565 <element name="spouse" type="ns:record" minOccurs="1" maxOccurs="1" nillable="true"/>
2566 </sequence>
2567 </complexType>
2568 ```
2569 </div>
2570
2571 An example XML instance of `ns__record` with its `name` string value set to
2572 `Joe`, `SSN` set to its default, and `spouse` set to NULL:
2573
2574 <div class="alt">
2575 ```xml
2576 <ns:record xmlns:ns="urn:types" ...>
2577 <name>Joe</name>
2578 <SSN>999</SSN>
2579 <spouse xsi:nil="true"/>
2580 </ns:record>
2581 ```
2582 </div>
2583
2584 @note In general, a smart pointer is simply declared as a `volatile` template
2585 in a gSOAP header file for soapcpp2:
2586
2587 ```cpp
2588 volatile template <class T> class NAMESPACE::shared_ptr;
2589 ```
2590
2591 @note The soapcpp2 tool generates code that uses `NAMESPACE::shared_ptr` and
2592 `NAMESPACE::make_shared` to create shared pointers to objects, where
2593 `NAMESPACE` is any valid C++ namespace such as `std` and `boost` if you have
2594 Boost installed.
2595
2596 🔝 [Back to table of contents](#)
2597
2598 ### Container and array members and their occurrence constraints {#toxsd9-9}
2599
2600 Class and struct data member types that are containers `std::deque`,
2601 `std::list`, `std::vector` and `std::set` are serialized as a collection of
2602 the values they contain. You can also serialize dynamic arrays, which is the
2603 alternative for C to store collections of data. Let's start with STL containers.
2604
2605 You can use `std::deque`, `std::list`, `std::vector`, and `std::set` containers
2606 by importing:
2607
2608 ```cpp
2609 #import "import/stl.h" // import all containers
2610 #import "import/stldeque.h" // import deque
2611 #import "import/stllist.h" // import list
2612 #import "import/stlvector.h" // import vector
2613 #import "import/stlset.h" // import set
2614 ```
2615
2616 For example, to use a vector data mamber to store names in a record:
2617
2618 ```cpp
2619 #import "import/stlvector.h"
2620 class ns__record
2621 {
2622 public:
2623 std::vector<std::string> names;
2624 uint64_t SSN;
2625 };
2626 ```
2627
2628 To limit the number of names in the vector within reasonable bounds, occurrence
2629 constraints are associated with the container. Occurrence constraints are of
2630 the form `minOccurs : maxOccurs`:
2631
2632 ```cpp
2633 #import "import/stlvector.h"
2634 class ns__record
2635 {
2636 public:
2637 std::vector<std::string> names 1:10;
2638 uint64_t SSN;
2639 };
2640 ```
2641
2642 This class maps to a complexType in the soapcpp2-generated schema:
2643
2644 <div class="alt">
2645 ```xml
2646 <complexType name="record">
2647 <sequence>
2648 <element name="name" type="xsd:string" minOccurs="1" maxOccurs="10"/>
2649 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1""/>
2650 </sequence>
2651 </complexType>
2652 ```
2653 </div>
2654
2655 @note In general, a container is simply declared as a template in a gSOAP
2656 header file for soapcpp2. All class templates are considered containers
2657 (except when declared `volatile`, see smart pointers). For example,
2658 `std::vector` is declared in `gsoap/import/stlvector.h` as:
2659
2660 ```cpp
2661 template <class T> class std::vector;
2662 ```
2663
2664 @note You can define and use your own containers. The soapcpp2 tool generates
2665 code that uses the following members of the `template <typename T> class C`
2666 container:
2667
2668 ```cpp
2669 void C::clear()
2670 C::iterator C::begin()
2671 C::const_iterator C::begin() const
2672 C::iterator C::end()
2673 C::const_iterator C::end() const
2674 size_t C::size() const
2675 C::iterator C::insert(C::iterator pos, const T& val)
2676 ```
2677
2678 @note For more details see the example `simple_vector` container with
2679 documentation in the package under `gsoap/samples/template`.
2680
2681 Because C does not support a container template library, we can use a
2682 dynamically-sized array of values. This array is declared as a size-pointer
2683 pair of members within a struct or class. The array size information is stored
2684 in a special size tag member with the name `__size` or `__sizeX`, where `X` can
2685 be any name, or by an `$int` member to identify the member as a special size
2686 tag:
2687
2688 ```cpp
2689 struct ns__record
2690 {
2691 $int sizeofnames; // array size
2692 char* *names; // array of char* names
2693 uint64_t SSN;
2694 };
2695 ```
2696
2697 This class maps to a complexType in the soapcpp2-generated schema:
2698
2699 <div class="alt">
2700 ```xml
2701 <complexType name="record">
2702 <sequence>
2703 <element name="name" type="xsd:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/>
2704 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1""/>
2705 </sequence>
2706 </complexType>
2707 ```
2708 </div>
2709
2710 To limit the number of names in the array within reasonable bounds, occurrence
2711 constraints are associated with the array size member. Occurrence constraints
2712 are of the form `minOccurs : maxOccurs`:
2713
2714 ```cpp
2715 struct ns__record
2716 {
2717 $int sizeofnames 1:10; // array size 1..10
2718 char* *names; // array of one to ten char* names
2719 uint64_t SSN;
2720 };
2721 ```
2722
2723 This class maps to a complexType in the soapcpp2-generated schema:
2724
2725 <div class="alt">
2726 ```xml
2727 <complexType name="record">
2728 <sequence>
2729 <element name="name" type="xsd:string" minOccurs="1" maxOccurs="10" nillable="true"/>
2730 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1""/>
2731 </sequence>
2732 </complexType>
2733 ```
2734 </div>
2735
2736 🔝 [Back to table of contents](#)
2737
2738 ### Tagged union members {#toxsd9-10}
2739
2740 A union member in a class or in a struct cannot be serialized unless a
2741 discriminating *variant selector* member is provided that tells the serializer
2742 which union field to serialize. This effectively creates a *tagged union*.
2743
2744 The variant selector is associated with the union as a selector-union pair of members.
2745 The variant selector is a member with the name `__union` or `__unionX`, where
2746 `X` can be any name, or by an `$int` member to identify the member as a variant
2747 selector tag:
2748
2749 ```cpp
2750 class ns__record
2751 {
2752 public:
2753 $int xORnORs; // variant selector with values SOAP_UNION_fieldname
2754 union choice
2755 {
2756 float x;
2757 int n;
2758 char *s;
2759 } u;
2760 std::string name;
2761 };
2762 ```
2763
2764 The variant selector values are auto-generated based on the union name `choice`
2765 and the names of its members `x`, `n`, and `s`:
2766
2767 - `xORnORs = SOAP_UNION_choice_x` when `u.x` is valid.
2768 - `xORnORs = SOAP_UNION_choice_n` when `u.n` is valid.
2769 - `xORnORs = SOAP_UNION_choice_s` when `u.s` is valid.
2770 - `xORnORs = 0` when none are valid (should only be used with great care,
2771 because XSD validation may fail when content is required but absent).
2772
2773 This class maps to a complexType with a sequence and choice in the
2774 soapcpp2-generated schema:
2775
2776 <div class="alt">
2777 ```xml
2778 <complexType name="record">
2779 <sequence>
2780 <choice>
2781 <element name="x" type="xsd:float" minOccurs="1" maxOccurs="1"/>
2782 <element name="n" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2783 <element name="s" type="xsd:string" minOccurs="0" maxOccurs="1" nillable="true"/>
2784 </choice>
2785 <element name="names" type="xsd:string" minOccurs="1" maxOccurs="1" nillable="true"/>
2786 </sequence>
2787 </complexType>
2788 ```
2789 </div>
2790
2791 An STL container or dynamic array of a union requires wrapping the variant
2792 selector and union member in a struct:
2793
2794 ```cpp
2795 class ns__record
2796 {
2797 public:
2798 std::vector<
2799 struct ns__data // data with a choice of x, n, or s
2800 {
2801 $int xORnORs; // variant selector with values SOAP_UNION_fieldname
2802 union choice
2803 {
2804 float x;
2805 int n;
2806 char *s;
2807 } u;
2808 }> data; // vector with data
2809 };
2810 ```
2811
2812 and an equivalent definition with a dynamic array instead of a `std::vector`
2813 (you can use this in C with structs):
2814
2815 ```cpp
2816 class ns__record
2817 {
2818 public:
2819 $int sizeOfdata; // size of dynamic array
2820 struct ns__data // data with a choice of x, n, or s
2821 {
2822 $int xORnORs; // variant selector with values SOAP_UNION_fieldname
2823 union choice
2824 {
2825 float x;
2826 int n;
2827 char *s;
2828 } u;
2829 } *data; // points to the data array of length sizeOfdata
2830 };
2831 ```
2832
2833 This maps to two complexTypes in the soapcpp2-generated schema:
2834
2835 <div class="alt">
2836 ```xml
2837 <complexType name="data">
2838 <choice>
2839 <element name="x" type="xsd:float" minOccurs="1" maxOccurs="1"/>
2840 <element name="n" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2841 <element name="s" type="xsd:string" minOccurs="0" maxOccurs="1" nillable="true"/>
2842 </choice>
2843 </complexType>
2844 <complexType name="record">
2845 <sequence>
2846 <element name="data" type="ns:data" minOccurs="0" maxOccurs="unbounded"/>
2847 </sequence>
2848 </complexType>
2849 ```
2850 </div>
2851
2852 The XML value space consists of a sequence of item elements each wrapped in an
2853 data element:
2854
2855 <div class="alt">
2856 ```xml
2857 <ns:record xmlns:ns="urn:types" ...>
2858 <data>
2859 <n>123</n>
2860 </data>
2861 <data>
2862 <x>3.1</x>
2863 </data>
2864 <data>
2865 <s>hello</s>
2866 </data>
2867 <data>
2868 <s>world</s>
2869 </data>
2870 </ns:record>
2871 ```
2872 </div>
2873
2874 To remove the wrapping data element, simply rename the wrapping struct and
2875 member to `__data` to make this member invisible to the serializer with the
2876 double underscore prefix naming convention. Also use a dynamic array instead
2877 of a STL container (you can use this in C with structs):
2878
2879 ```cpp
2880 class ns__record
2881 {
2882 public:
2883 $int sizeOfdata; // size of dynamic array
2884 struct __data // contains choice of x, n, or s
2885 {
2886 $int xORnORs; // variant selector with values SOAP_UNION_fieldname
2887 union choice
2888 {
2889 float x;
2890 int n;
2891 char *s;
2892 } u;
2893 } *__data; // points to the data array of length sizeOfdata
2894 };
2895 ```
2896
2897 This maps to a complexType in the soapcpp2-generated schema:
2898
2899 <div class="alt">
2900 ```xml
2901 <complexType name="record">
2902 <sequence minOccurs="0" maxOccurs="unbounded">
2903 <choice>
2904 <element name="x" type="xsd:float" minOccurs="1" maxOccurs="1"/>
2905 <element name="n" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2906 <element name="s" type="xsd:string" minOccurs="0" maxOccurs="1" nillable="true"/>
2907 </choice>
2908 </sequence>
2909 </complexType>
2910 ```
2911 </div>
2912
2913 The XML value space consists of a sequence of `<x>`, `<n>`, and/or `<s>`
2914 elements:
2915
2916 <div class="alt">
2917 ```xml
2918 <ns:record xmlns:ns="urn:types" ...>
2919 <n>123</n>
2920 <x>3.1</x>
2921 <s>hello</s>
2922 <s>world</s>
2923 </ns:record>
2924 ```
2925 </div>
2926
2927 Please note that structs, classes, and unions are unnested by soapcpp2 (as in
2928 the C standard of nested structs and unions). Therefore, the `choice` union in
2929 the `ns__record` class is redeclared at the top level despite its nesting
2930 within the `ns__record` class. This means that you will have to choose a
2931 unique name for each nested struct, class, and union.
2932
2933 🔝 [Back to table of contents](#)
2934
2935 ### Tagged void pointer members {#toxsd9-11}
2936
2937 To serialize data pointed to by `void*` requires run-time type information that
2938 tells the serializer what type of data to serialize by means of a *tagged void
2939 pointer*. This type information is stored in a special type tag member of a
2940 struct/class with the name `__type` or `__typeX`, where `X` can be any name, or
2941 alternatively by an `$int` special member of any name as a type tag:
2942
2943 ```cpp
2944 class ns__record
2945 {
2946 public:
2947 $int typeOfdata; // type tag with values SOAP_TYPE_T
2948 void *data; // points to some data of type T
2949 };
2950 ```
2951
2952 A type tag member has nonzero values `SOAP_TYPE_T` where `T` is the name of a
2953 struct/class or the name of a primitive type, such as `int`, `std__string` (for
2954 `std::string`), `string` (for `char*`).
2955
2956 This class maps to a complexType with a sequence in the soapcpp2-generated
2957 schema:
2958
2959 <div class="alt">
2960 ```xml
2961 <complexType name="record">
2962 <sequence>
2963 <element name="data" type="xsd:anyType" minOccurs="0" maxOccurs="1"/>
2964 </sequence>
2965 </complexType>
2966 ```
2967 </div>
2968
2969 The XML value space consists of the XML value space of the type with the
2970 addition of an `xsi:type` attribute to the enveloping element:
2971
2972 <div class="alt">
2973 ```xml
2974 <ns:record xmlns:ns="urn:types" ...>
2975 <data xsi:type="xsd:int">123</data>
2976 </ns:record>
2977 ```
2978 </div>
2979
2980 This `xsi:type` attribute is important for the receiving end to distinguish
2981 the type of data to instantiate. The receiver cannot deserialize the data
2982 without an `xsd:type` attribute.
2983
2984 You can find the `SOAP_TYPE_T` name of each serializable type in the
2985 auto-generated soapStub.h file.
2986
2987 Also all serializable C++ classes have a virtual `int T::soap_type()` member
2988 that returns their `SOAP_TYPE_T` value that you can use.
2989
2990 When the `void*` pointer is NULL or when `typeOfdata` is zero, the data is not
2991 serialized.
2992
2993 An STL container or dynamic array of `void*` pointers to `xsd:anyType` data
2994 requires wrapping the type tag and `void*` members in a struct:
2995
2996 ```cpp
2997 class ns__record
2998 {
2999 public:
3000 std::vector<
3001 struct ns__data // data with an xsd:anyType item
3002 {
3003 $int typeOfitem; // type tag with values SOAP_TYPE_T
3004 void *item; // points to some item of type T
3005 }> data; // vector with data
3006 };
3007 ```
3008
3009 and an equivalent definition with a dynamic array instead of a `std::vector`
3010 (you can use this in C with structs):
3011
3012 ```cpp
3013 class ns__record
3014 {
3015 public:
3016 $int sizeOfdata; // size of dynamic array
3017 struct ns__data // data with an xsd:anyType item
3018 {
3019 $int typeOfitem; // type tag with values SOAP_TYPE_T
3020 void *item; // points to some item of type T
3021 } *data; // points to the data array of length sizeOfdata
3022 };
3023 ```
3024
3025 This maps to two complexTypes in the soapcpp2-generated schema:
3026
3027 <div class="alt">
3028 ```xml
3029 <complexType name="data">
3030 <sequence>
3031 <element name="item" type="xsd:anyType" minOccurs="1" maxOccurs="1" nillable="true"/>
3032 </sequence>
3033 </complexType>
3034 <complexType name="record">
3035 <sequence>
3036 <element name="data" type="ns:data" minOccurs="0" maxOccurs="unbounded"/>
3037 </sequence>
3038 </complexType>
3039 ```
3040 </div>
3041
3042 The XML value space consists of a sequence of item elements each wrapped in a
3043 data element:
3044
3045 <div class="alt">
3046 ```xml
3047 <ns:record xmlns:ns="urn:types" ...>
3048 <data>
3049 <item xsi:type="xsd:int">123</item>
3050 </data>
3051 <data>
3052 <item xsi:type="xsd:double">3.1</item>
3053 </data>
3054 <data>
3055 <item xsi:type="xsd:string">abc</item>
3056 </data>
3057 </ns:record>
3058 ```
3059 </div>
3060
3061 To remove the wrapping data elements, simply rename the wrapping struct and
3062 member to `__data` to make this member invisible to the serializer with the
3063 double underscore prefix naming convention. Also use a dynamic array instead
3064 of a STL container (you can use this in C with structs):
3065
3066 ```cpp
3067 class ns__record
3068 {
3069 public:
3070 $int sizeOfdata; // size of dynamic array
3071 struct __data // contains xsd:anyType item
3072 {
3073 $int typeOfitem; // type tag with values SOAP_TYPE_T
3074 void *item; // points to some item of type T
3075 } *__data; // points to the data array of length sizeOfdata
3076 };
3077 ```
3078
3079 This maps to a complexType in the soapcpp2-generated schema:
3080
3081 <div class="alt">
3082 ```xml
3083 <complexType name="record">
3084 <sequence minOccurs="0" maxOccurs="unbounded">
3085 <element name="item" type="xsd:anyType" minOccurs="1" maxOccurs="1"/>
3086 </sequence>
3087 </complexType>
3088 ```
3089 </div>
3090
3091 The XML value space consists of a sequence of data elements:
3092
3093 <div class="alt">
3094 ```xml
3095 <ns:record xmlns:ns="urn:types" ...>
3096 <item xsi:type="xsd:int">123</item>
3097 <item xsi:type="xsd:double">3.1</item>
3098 <item xsi:type="xsd:string">abc</item>
3099 </ns:record>
3100 ```
3101 </div>
3102
3103 Again, please note that structs, classes, and unions are unnested by soapcpp2
3104 (as in the C standard of nested structs and unions). Therefore, the `__data`
3105 struct in the `ns__record` class is redeclared at the top level despite its
3106 nesting within the `ns__record` class. This means that you will have to choose
3107 a unique name for each nested struct, class, and union.
3108
3109 @see Section [XSD type bindings](#typemap2).
3110
3111 🔝 [Back to table of contents](#)
3112
3113 ### Adding get and set methods {#toxsd9-12}
3114
3115 A public `get` method may be added to a class or struct, which will be
3116 triggered by the deserializer. This method will be invoked right after the
3117 instance is populated by the deserializer. The `get` method can be used to
3118 update or verify deserialized content. It should return `SOAP_OK` or set
3119 `soap::error` to a nonzero error code and return it.
3120
3121 A public `set` method may be added to a class or struct, which will be
3122 triggered by the serializer. The method will be invoked just before the
3123 instance is serialized. Likewise, the `set` method should return `SOAP_OK` or
3124 set set `soap::error` to a nonzero error code and return it.
3125
3126 For example, adding a `set` and `get` method to a class declaration:
3127
3128 ```cpp
3129 class ns__record
3130 {
3131 public:
3132 int set(struct soap*); // triggered before serialization
3133 int get(struct soap*); // triggered after deserialization
3134 ...
3135 };
3136 ```
3137
3138 To add these and othe rmethods to classes and structs with wsdl2h and
3139 `typemap.dat`, please see [class/struct member additions](#typemap3).
3140
3141 🔝 [Back to table of contents](#)
3142
3143 ### Operations on classes and structs {#toxsd9-13}
3144
3145 The following functions/macros are generated by soapcpp2 for each type `T`,
3146 which should make it easier to send, receive, and copy XML data in C and in
3147 C++:
3148
3149 - `int soap_write_T(struct soap*, T*)` writes an instance of `T` to a file via
3150 file descriptor `int soap::sendfd)` or to a stream via `std::ostream
3151 *soap::os` (C++ only) or saves into a NUL-terminated string by setting
3152 `const char **soap::os` to a string pointer to be set (C only). Returns
3153 `SOAP_OK` on success or an error code, also stored in `soap->error`.
3154
3155 - `int soap_read_T(struct soap*, T*)` reads an instance of `T` from a file via
3156 file descriptor `int soap::recvfd)` or from a stream via `std::istream
3157 *soap::is` (C++ only) or reads from a NUL-termianted string `const char
3158 *soap::is` (C only). Returns `SOAP_OK` on success or an error code, also
3159 stored in `soap->error`.
3160
3161 - `void soap_default_T(struct soap*, T*)` sets an instance `T` to its default
3162 value, resetting members of a struct to their initial values (for classes we
3163 use method `T::soap_default`, see below).
3164
3165 - `T * soap_dup_T(struct soap*, T *dst, const T *src)` (soapcpp2 option `-Ec`)
3166 deep copy `src` into `dst`, replicating all deep cycles and shared pointers
3167 when a managing soap context is provided as argument. When `dst` is NULL,
3168 allocates space for `dst`. Deep copy is a tree when argument is NULL, but the
3169 presence of deep cycles will lead to non-termination. Use flag
3170 `SOAP_XML_TREE` with managing context to copy into a tree without cycles and
3171 pointers to shared objects. Returns `dst` (or allocated space when `dst` is
3172 NULL).
3173
3174 - `void soap_del_T(const T*)` (soapcpp2 option `-Ed`) deletes all
3175 heap-allocated members of this object by deep deletion ONLY IF this object
3176 and all of its (deep) members are not managed by a soap context AND the deep
3177 structure is a tree (no cycles and co-referenced objects by way of multiple
3178 (non-smart) pointers pointing to the same data). Can be safely used after
3179 `soap_dup(NULL)` to delete the deep copy. Does not delete the object itself.
3180
3181 When in C++ mode, soapcpp2 tool adds several methods to classes in addition to
3182 adding a default constructor and destructor (when these were not explicitly
3183 declared).
3184
3185 The public methods added to a class `T`:
3186
3187 - `virtual int T::soap_type(void)` returns a unique type ID (`SOAP_TYPE_T`).
3188 This numeric ID can be used to distinguish base from derived instances.
3189
3190 - `virtual void T::soap_default(struct soap*)` sets all data members to
3191 default values.
3192
3193 - `virtual void T::soap_serialize(struct soap*) const` serializes object to
3194 prepare for SOAP 1.1/1.2 encoded output (or with `SOAP_XML_GRAPH`) by
3195 analyzing its (cyclic) structures.
3196
3197 - `virtual int T::soap_put(struct soap*, const char *tag, const char *type) const`
3198 emits object in XML, compliant with SOAP 1.1 encoding style, return error
3199 code or `SOAP_OK`. Requires `soap_begin_send(soap)` and
3200 `soap_end_send(soap)`.
3201
3202 - `virtual int T::soap_out(struct soap*, const char *tag, int id, const char *type) const`
3203 emits object in XML, with tag and optional id attribute and `xsi:type`,
3204 return error code or `SOAP_OK`. Requires `soap_begin_send(soap)` and
3205 `soap_end_send(soap)`.
3206
3207 - `virtual void * T::soap_get(struct soap*, const char *tag, const char *type)`
3208 Get object from XML, compliant with SOAP 1.1 encoding style, return pointer
3209 to object or NULL on error. Requires `soap_begin_recv(soap)` and
3210 `soap_end_recv(soap)`.
3211
3212 - `virtual void *soap_in(struct soap*, const char *tag, const char *type)`
3213 Get object from XML, with matching tag and type (NULL matches any tag and
3214 type), return pointer to object or NULL on error. Requires
3215 `soap_begin_recv(soap)` and `soap_end_recv(soap)`
3216
3217 - `virtual T * T::soap_alloc(void) const` returns a new object of type `T`,
3218 default initialized and not managed by a soap context.
3219
3220 - `virtual T * T::soap_dup(struct soap*) const` (soapcpp2 option `-Ec`) returns
3221 a duplicate of this object by deep copying, replicating all deep cycles and
3222 shared pointers when a managing soap context is provided as argument. Deep
3223 copy is a tree when argument is NULL, but the presence of deep cycles will
3224 lead to non-termination. Use flag `SOAP_XML_TREE` with the managing context
3225 to copy into a tree without cycles and pointers to shared objects.
3226
3227 - `virtual void T::soap_del() const` (soapcpp2 option `-Ed`) deletes all
3228 heap-allocated members of this object by deep deletion ONLY IF this object
3229 and all of its (deep) members are not managed by a soap context AND the deep
3230 structure is a tree (no cycles and co-referenced objects by way of multiple
3231 (non-smart) pointers pointing to the same data). Can be safely used after
3232 `soap_dup(NULL)` to delete the deep copy. Does not delete the object itself.
3233
3234 Also for C++, there are four variations of `soap_new_T` for
3235 class/struct/template type `T` that soapcpp2 auto-generates to create instances
3236 on a context-managed heap:
3237
3238 - `T * soap_new_T(struct soap*)` returns a new instance of `T` with default data
3239 member initializations that are set with the soapcpp2 auto-generated `void
3240 T::soap_default(struct soap*)` method), but ONLY IF the soapcpp2
3241 auto-generated default constructor is used that invokes `soap_default()` and
3242 was not replaced by a user-defined default constructor.
3243
3244 - `T * soap_new_T(struct soap*, int n)` returns an array of `n` new instances of
3245 `T`. Similar to the above, instances are initialized.
3246
3247 - `T * soap_new_req_T(struct soap*, ...)` returns a new instance of `T` and sets
3248 the required data members to the values specified in `...`. The required data
3249 members are those with nonzero minOccurs, see the subsections on
3250 [(smart) pointer members and their occurrence constraints](#toxsd9-8) and
3251 [container and array members and their occurrence constraints](#toxsd9-9).
3252
3253 - `T * soap_new_set_T(struct soap*, ...)` returns a new instance of `T` and sets
3254 the public/serializable data members to the values specified in `...`.
3255
3256 The above functions can be invoked with a NULL `soap` context, but we will be
3257 responsible to use `delete T` to remove this instance from the unmanaged heap.
3258
3259 🔝 [Back to table of contents](#)
3260
3261 Special classes and structs {#toxsd10}
3262 ---------------------------
3263
3264 ### SOAP encoded arrays {#toxsd10-1}
3265
3266 A class or struct with the following layout is a one-dimensional SOAP encoded
3267 Array type:
3268
3269 ```cpp
3270 class ArrayOfT
3271 {
3272 public:
3273 T *__ptr; // array pointer
3274 int __size; // array size
3275 };
3276 ```
3277
3278 where `T` is the array element type. A multidimensional SOAP Array is:
3279
3280 ```cpp
3281 class ArrayOfT
3282 {
3283 public:
3284 T *__ptr; // array pointer
3285 int __size[N]; // array size of each dimension
3286 };
3287 ```
3288
3289 where `N` is the constant number of dimensions. The pointer points to an array
3290 of `__size[0]*__size[1]* ... * __size[N-1]` elements.
3291
3292 This maps to a complexType restriction of SOAP-ENC:Array in the
3293 soapcpp2-generated schema:
3294
3295 <div class="alt">
3296 ```xml
3297 <complexType name="ArrayOfT">
3298 <complexContent>
3299 <restriction base="SOAP-ENC:Array">
3300 <sequence>
3301 <element name="item" type="T" minOccurs="0" maxOccurs="unbounded" nillable="true"/>
3302 </sequence>
3303 <attribute ref="SOAP-ENC:arrayType" WSDL:arrayType="ArrayOfT[]"/>
3304 </restriction>
3305 </complexContent>
3306 </complexType>
3307 ```
3308 </div>
3309
3310 The name of the class can be arbitrary. We often use `ArrayOfT` without a
3311 prefix to distinguish arrays from other classes and structs.
3312
3313 With SOAP 1.1 encoding, an optional offset member can be added that controls
3314 the start of the index range for each dimension:
3315
3316 ```cpp
3317 class ArrayOfT
3318 {
3319 public:
3320 T *__ptr; // array pointer
3321 int __size[N]; // array size of each dimension
3322 int __offset[N]; // array offsets to start each dimension
3323 };
3324 ```
3325
3326 For example, we can define a matrix of floats as follows:
3327
3328 ```cpp
3329 class Matrix
3330 {
3331 public:
3332 double *__ptr;
3333 int __size[2];
3334 };
3335 ```
3336
3337 The following code populates the matrix and serializes it in XML:
3338
3339 ```cpp
3340 soap *soap = soap_new1(SOAP_XML_INDENT);
3341 Matrix A;
3342 double a[6] = { 1, 2, 3, 4, 5, 6 };
3343 A.__ptr = a;
3344 A.__size[0] = 2;
3345 A.__size[1] = 3;
3346 soap_write_Matrix(soap, &A);
3347 ```
3348
3349 Matrix A is serialized as an array with 2x3 values:
3350
3351 <div class="alt">
3352 ```xml
3353 <SOAP-ENC:Array SOAP-ENC:arrayType="xsd:double[2,3]" ...>
3354 <item>1</item>
3355 <item>2</item>
3356 <item>3</item>
3357 <item>4</item>
3358 <item>5</item>
3359 <item>6</item>
3360 </SOAP-ENC:Array>
3361 ```
3362 </div>
3363
3364 🔝 [Back to table of contents](#)
3365
3366 ### XSD hexBinary and base64Binary types {#toxsd10-2}
3367
3368 A special case of a one-dimensional array is used to define `xsd:hexBinary` and
3369 `xsd:base64Binary` types when the pointer type is `unsigned char`:
3370
3371 ```cpp
3372 class xsd__hexBinary
3373 {
3374 public:
3375 unsigned char *__ptr; // points to raw binary data
3376 int __size; // size of data
3377 };
3378 ```
3379
3380 and
3381
3382 ```cpp
3383 class xsd__base64Binary
3384 {
3385 public:
3386 unsigned char *__ptr; // points to raw binary data
3387 int __size; // size of data
3388 };
3389 ```
3390
3391 🔝 [Back to table of contents](#)
3392
3393 ### MIME/MTOM attachment binary types {#toxsd10-3}
3394
3395 A class or struct with a binary content layout can be extended to support
3396 MIME/MTOM (and older DIME) attachments, such as in `<xop:Include>` elements:
3397
3398 ```cpp
3399 //gsoap xop schema import: http://www.w3.org/2004/08/xop/include
3400 class _xop__Include
3401 {
3402 public:
3403 unsigned char *__ptr; // points to raw binary data
3404 int __size; // size of data
3405 char *id; // NULL to generate an id, or set to a unique UUID
3406 char *type; // MIME type of the data
3407 char *options; // optional description of MIME attachment
3408 };
3409 ```
3410
3411 Attachments are beyond the scope of this article. The `SOAP_ENC_MIME` and
3412 `SOAP_ENC_MTOM` context flag must be set to enable attachments. See the
3413 [gSOAP user guide](http://www.genivia.com/doc/soapdoc2.html) for more details.
3414
3415 🔝 [Back to table of contents](#)
3416
3417 ### Wrapper class/struct with simpleContent {#toxsd10-4}
3418
3419 A class or struct with the following layout is a complexType that wraps
3420 simpleContent:
3421
3422 ```cpp
3423 class ns__simple
3424 {
3425 public:
3426 T __item;
3427 };
3428 ```
3429
3430 The type `T` is a primitive type (`bool`, `enum`, `time_t`, numeric and string
3431 types), `xsd__hexBinary`, `xsd__base64Binary`, and custom serializers, such as
3432 `xsd__dateTime`.
3433
3434 This maps to a complexType with simpleContent in the soapcpp2-generated schema:
3435
3436 <div class="alt">
3437 ```xml
3438 <complexType name="simple">
3439 <simpleContent>
3440 <extension base="T"/>
3441 </simpleContent>
3442 </complexType>
3443 ```
3444 </div>
3445
3446 A wrapper class/struct may include any number of attributes declared with `@`.
3447
3448 🔝 [Back to table of contents](#)
3449
3450 ### DOM anyType and anyAttribute {#toxsd10-5}
3451
3452 Use of a DOM is optional and enabled by `#import "dom.h"` to use the DOM
3453 `xsd__anyType` element node and `xsd__anyAttribute` attribute node:
3454
3455 ```cpp
3456 #import "dom.h"
3457
3458 class ns__record
3459 {
3460 public:
3461 @xsd__anyAttribute attributes; // optional DOM attributes
3462 ...
3463 xsd__anyType *name; // optional DOM element (pointer means minOccurs=0)
3464 xsd__anyType address; // required DOM element (minOccurs=1)
3465 xsd__anyType email 0; // optional DOM element (minOccurs=0)
3466 };
3467 ```
3468
3469 where `name` contains XML stored in a DOM node set and `attributes` is a list
3470 of all visibly rendered attributes. The name `attributes` is arbitrary and any
3471 name will suffice.
3472
3473 You should place the `xsd__anyType` members at the end of the struct or class.
3474 This ensures that the DOM members are populated last as a "catch all". A
3475 member name starting with double underscore is a wildcard member name and
3476 matches any XML tag. These members are placed at the end of a struct or class
3477 automatically by soapcpp2.
3478
3479 An `#import "dom.h"` import is automatically added by wsdl2h with option `-d`
3480 to bind `xsd:anyType` to DOM nodes, and also to populate `xsd:any`,
3481 `xsd:anyAttribute` and `xsd:mixed` XML content:
3482
3483 ```cpp
3484 #import "dom.h"
3485
3486 class ns__record
3487 {
3488 public:
3489 ...
3490 @xsd__anyAttribute __anyAttribute; // optional DOM attributes
3491 std::vector<xsd__anyType> __any 0; // optional DOM elements (minOccurs=0)
3492 xsd__anyType __mixed 0; // optional mixed content (minOccurs=0)
3493 };
3494 ```
3495
3496 where the members prefixed with `__` are "invisible" to the XML parser, meaning
3497 that these members are not bound to XML tag names.
3498
3499 In C you can use a dynamic arrary instead of `std::vector`:
3500
3501 ```cpp
3502 #import "dom.h"
3503
3504 struct ns__record
3505 {
3506 ...
3507 @xsd__anyAttribute __anyAttribute; // optional DOM attributes
3508 $int __sizeOfany; // size of the array
3509 xsd__anyType *__any; // optional DOM elements (pointer means minOccurs=0)
3510 xsd__anyType __mixed 0; // optional mixed content (minOccurs=0)
3511 };
3512 ```
3513
3514 Classes can inherit DOM, which enables full use of polymorphism with one base
3515 DOM class:
3516
3517 ```cpp
3518 #import "dom.h"
3519
3520 class ns__record : public xsd__anyType
3521 {
3522 ...
3523 std::vector<xsd__anyType*> array; // array of objects of any class
3524 };
3525 ```
3526
3527 This permits an `xsd__anyType` pointer to refer to a derived class such as
3528 `ns__record`, which will be serialized with an `xsi:type` attribute that is
3529 set to "ns:record". The `xsi:type` attributes add the necessary type information
3530 to distinguish the XML content from the DOM base type. This is important for
3531 the receiving end: without `xsd:type` attributes with type names, only base DOM
3532 objects are recognized and instantiated.
3533
3534 Because C lacks OOP principles such as class inheritance and polymorphism, you
3535 will need to use the special [`void*` members](#toxsd9-11) to serialize data
3536 pointed to by a `void*` member.
3537
3538 To ensure that wsdl2h generates pointer-based `xsd__anyType` DOM nodes with
3539 option `-d` for `xsd:any`, add the following line to `typemap.dat`:
3540
3541 xsd__any = | xsd__anyType*
3542
3543 This lets wsdl2h produce class/struct members and containers with
3544 `xsd__anyType*` for `xsd:any` instead of `xsd__anyType`. To just force all
3545 `xsd:anyType` uses to be pointer-based, declare in `typemap.dat`:
3546
3547 xsd__anyType = | xsd__anyType*
3548
3549 If you use wsdl2h with option `-p` with option `-d` then every class will
3550 inherit DOM as shown above. Without option `-d`, an `xsd__anyType` type is
3551 generated to serve as the root type in the type hierarchy:
3552
3553 ```cpp
3554 class xsd__anyType { _XML __item; struct soap *soap; };
3555
3556 class ns__record : public xsd__anyType
3557 {
3558 ...
3559 };
3560 ```
3561
3562 where the `_XML __item` member holds any XML content as a literal XML string.
3563
3564 To use the DOM API, compile `dom.c` (or `dom.cpp` for C++), or link with
3565 `-lgsoapssl` (or `-lgsoapssl++` for C++).
3566
3567 @see Documentation of [XML DOM and XPath](http://www.genivia.com/doc/dom/html)
3568 for more details.
3569
3570 🔝 [Back to table of contents](#)
3571
3572 Directives {#directives}
3573 ==========
3574
3575 You can use `//gsoap` directives in the gSOAP header file with the data binding
3576 interface for soapcpp2. These directives are used to configure the code
3577 generated by soapcpp2 by declaring various. properties of Web services and XML
3578 schemas. When using the wsdl2h tool, you will notice that wsdl2h generates
3579 directives automatically based on the WSDL and XSD input.
3580
3581 Service directives are applicable to service and operations described by WSDL.
3582 Schema directives are applicable to types, elements, and attributes defined by
3583 XML schemas.
3584
3585 🔝 [Back to table of contents](#)
3586
3587 Service directives {#directives-1}
3588 ------------------
3589
3590 A service directive must start at a new line and is of the form:
3591
3592 ```cpp
3593 //gsoap <prefix> service <property>: <value>
3594 ```
3595
3596 where `<prefix>` is the XML namespace prefix of a service binding. The
3597 `<property>` and `<value>` fields are one of the following:
3598
3599 property | value
3600 --------------- | -----
3601 `name` | name of the service, optionally followed by text describing the service
3602 `namespace` | URI of the WSDL targetNamespace
3603 `documentation` | text describing the service (see also the `name` property), multiple permitted
3604 `doc` | same as above, shorthand form
3605 `style` | `document` (default) SOAP messaging style or `rpc` for SOAP RPC
3606 `encoding` | `literal` (default), `encoded` for SOAP encoding, or a custom URI
3607 `protocol` | specifies SOAP or REST, see below
3608 `port` | URL of the service endpoint, usually an http or https address
3609 `transport` | URI declaration of the transport, usually `http://schemas.xmlsoap.org/soap/http`
3610 `definitions` | name of the WSDL definitions/\@name
3611 `type` | name of the WSDL definitions/portType/\@name (WSDL2.0 interface/\@name)
3612 `binding` | name of the WSDL definitions/binding/\@name
3613 `portName` | name of the WSDL definitions/service/port/\@name
3614 `portType` | an alias for the `type` property
3615 `interface` | an alias for the `type` property
3616 `location` | an alias for the `port` property
3617 `endpoint` | an alias for the `port` property
3618
3619 The service `name` and `namespace` properties are required in order to generate
3620 a valid WSDL with soapcpp2. The other properties are optional.
3621
3622 The `style` and `encoding` property defaults are changed with soapcpp2 option
3623 `-e` to `rpc` and `encoded`, respectively.
3624
3625 The `protocol` property is `SOAP` by default (SOAP 1.1). Protocol property
3626 values are:
3627
3628 protocol value | description
3629 -------------- | -----------
3630 `SOAP` | SOAP transport, supporting both SOAP 1.1 and 1.2
3631 `SOAP1.1` | SOAP 1.1 transport (same as soapcpp2 option `-1`)
3632 `SOAP1.2` | SOAP 1.2 transport (same as soapcpp2 option `-2`)
3633 `SOAP-GET` | one-way SOAP 1.1 or 1.2 with HTTP GET
3634 `SOAP1.1-GET` | one-way SOAP 1.1 with HTTP GET
3635 `SOAP1.2-GET` | one-way SOAP 1.2 with HTTP GET
3636 `HTTP` | non-SOAP REST protocol with HTTP POST
3637 `POST` | non-SOAP REST protocol with HTTP POST
3638 `GET` | non-SOAP REST protocol with HTTP GET
3639 `PUT` | non-SOAP REST protocol with HTTP PUT
3640 `DELETE` | non-SOAP REST protocol with HTTP DELETE
3641
3642 You can bind service operations to the WSDL namespace of a service by using the
3643 namespace prefix as part of the identifier name of the function that defines
3644 the service operation:
3645
3646 ```cpp
3647 int prefix__func(arg1, arg2, ..., argn, result);
3648 ```
3649
3650 You can override the `port` endpoint URL at runtime in the auto-generated
3651 `soap_call_prefix__func` service call (C/C++ client side) and in the C++ proxy
3652 class service call.
3653
3654 🔝 [Back to table of contents](#)
3655
3656 Service method directives {#directives-2}
3657 -------------------------
3658
3659 Service properties are applicable to a service and to all of its operations.
3660 Service method directives are specifically applicable to a service operation.
3661
3662 A service method directive is of the form:
3663
3664 ```cpp
3665 //gsoap <prefix> service method-<property>: <method> <value>
3666 ```
3667
3668 where `<prefix>` is the XML namespace prefix of a service binding and
3669 `<method>` is the unqualified name of a service operation. The `<property>`
3670 and `<value>` fields are one of the following:
3671
3672 method property | value
3673 --------------------------- | -----
3674 `method-documentation` | text describing the service operation
3675 `method` | same as above, shorthand form
3676 `method-action` | `""` or URI SOAPAction HTTP header, or URL query string for REST protocols
3677 `method-input-action` | `""` or URI SOAPAction HTTP header of service request messages
3678 `method-output-action` | `""` or URI SOAPAction HTTP header of service response messages
3679 `method-fault-action` | `""` or URI SOAPAction HTTP header of service fault messages
3680 `method-header-part` | member name of the `SOAP_ENV__Header` struct used in SOAP Header
3681 `method-input-header-part` | member name of the `SOAP_ENV__Header` struct used in SOAP Headers of requests
3682 `method-output-header-part` | member name of the `SOAP_ENV__Header` struct used in SOAP Headers of responses
3683 `method-fault` | type name of a struct or class member used in `SOAP_ENV__Details` struct
3684 `method-mime-type` | REST content type or SOAP MIME attachment content type(s)
3685 `method-input-mime-type` | REST content type or SOAP MIME attachment content type(s) of request message
3686 `method-output-mime-type` | REST content type or SOAP MIME attachment content type(s) of response message
3687 `method-style` | `document` or `rpc`
3688 `method-encoding` | `literal`, `encoded`, or a custom URI for encodingStyle of messages
3689 `method-response-encoding` | `literal`, `encoded`, or a custom URI for encodingStyle of response messages
3690 `method-protocol` | SOAP or REST, see [service directives](#directives-1)
3691
3692 The `method-header-part` properties can be repeated for a service operation to
3693 declare multiple SOAP Header parts that the service operation requires. You
3694 can use `method-input-header-part` and `method-output-header-part` to
3695 differentiate between request and response messages.
3696
3697 The `method-fault` property can be repeated for a service operation to declare
3698 multiple faults that the service operation may return.
3699
3700 The `method-action` property serves two purposes:
3701
3702 -# To set the SOAPAction header for SOAP protocols, i.e. sets the
3703 definitions/binding/operation/SOAP:operation/\@soapAction.
3704
3705 -# To set the URL query string for endpoints with REST protocols, i.e. sets the
3706 definitions/binding/operation/HTTP:operation/\@location, which specifies
3707 a URL query string (starts with a `?`) to complete the service endpoint URL
3708 or extends the endpoint URL with a local path (starts with a `/`).
3709
3710 Use `method-input-action` and `method-output-action` to differentiate the
3711 SOAPAction between SOAP request and response messages.
3712
3713 You can always override the port endpoint URL and action values at runtime in
3714 the auto-generated `soap_call_prefix__func` service call (C/C++ client side)
3715 and in the auto-generated C++ proxy class service calls. A runtime NULL
3716 endpoint URL and/or action uses the defaults set by these directives.
3717
3718 The `method-mime-type` property serves two purposes:
3719
3720 -# To set the type of MIME/MTOM attachments used with SOAP protocols. Multiple
3721 attachment types can be declared for a SOAP service operation, i.e. adds
3722 definitions/binding/operation/input/MIME:multipartRelated/MIME:part/MIME:content/\@type
3723 for each type specified.
3724
3725 -# To set the MIME type of a REST operation. This replaces XML declared in
3726 WSDL by definitions/binding/operation/(input|output)/MIME:mimeXml with
3727 MIME:content/\@type. Use `application/x-www-form-urlencoded` with REST POST
3728 and PUT protocols to send encoded form data automatically instead of XML.
3729 Only primitive type values can be transmitted with form data, such as
3730 numbers and strings, i.e. only types that are legal to use as
3731 [attributes members](#toxsd9-5).
3732
3733 Use `method-input-mime-type` and `method-output-mime-type` to differentiate the
3734 attachment types between SOAP request and response messages.
3735
3736 🔝 [Back to table of contents](#)
3737
3738 Schema directives {#directives-3}
3739 -----------------
3740
3741 A schema directive is of the form:
3742
3743 ```cpp
3744 //gsoap <prefix> schema <property>: <value>
3745 ```
3746
3747 where `<prefix>` is the XML namespace prefix of a schema. The `<property>` and
3748 `<value>` fields are one of the following:
3749
3750 property | value
3751 --------------- | -----
3752 `namespace` | URI of the XSD targetNamespace
3753 `namespace2` | alternate URI for the XSD namespace (i.e. URI is also accepted by the XML parser)
3754 `import` | URI of imported namespace
3755 `form` | `unqualified` (default) or `qualified` local element and attribute form defaults
3756 `elementForm` | `unqualified` (default) or `qualified` local element form default
3757 `attributeForm` | `unqualified` (default) or `qualified` local attribute form default
3758 `typed` | `no` (default) or `yes` for serializers to add `xsi:type` attributes to XML
3759
3760 To learn more about the local form defaults, see [qualified and unqualified members.](#toxsd9-6)
3761
3762 The `typed` property is implicitly `yes` when soapcpp2 option `-t` is used.
3763
3764 🔝 [Back to table of contents](#)
3765
3766 Schema type directives {#directives-4}
3767 ----------------------
3768
3769 A schema type directive is of the form:
3770
3771 ```cpp
3772 //gsoap <prefix> schema type-<property>: <name> <value>
3773 //gsoap <prefix> schema type-<property>: <name>::<member> <value>
3774 ```
3775
3776 where `<prefix>` is the XML namespace prefix of a schema and `<name>` is an
3777 unqualified name of a C/C++ type, and the optional `<member>` is a class/struct
3778 members or enum constant.
3779
3780 You can describe a type:
3781
3782 type property | value
3783 -------------------- | -----
3784 `type-documentation` | text describing the schema type
3785 `type` | same as above, shorthand form
3786
3787 For example, you can add a description to an enumeration:
3788
3789 ```cpp
3790 //gsoap ns schema type: Vowels The letters A, E, I, O, U, and sometimes Y
3791 //gsoap ns schema type: Vowels::Y A vowel, sometimes
3792 enum class ns__Vowels : char { A = 'A', E = 'E', I = 'I', O = 'O', U = 'U', Y = 'Y' };
3793 ```
3794
3795 This documented enumeration maps to a simpleType restriction of `xsd:string` in
3796 the soapcpp2-generated schema:
3797
3798 <div class="alt">
3799 ```xml
3800 <simpleType name="Vowels">
3801 <annotation>
3802 <documentation>The letters A, E, I, O, U, and sometimes Y</documentation>
3803 </annotation>
3804 <restriction base="xsd:string">
3805 <enumeration value="A"/>
3806 <enumeration value="E"/>
3807 <enumeration value="I"/>
3808 <enumeration value="O"/>
3809 <enumeration value="U"/>
3810 <enumeration value="Y">
3811 <annotation>
3812 <documentation>A vowel, sometimes</documentation>
3813 </annotation>
3814 <enumeration/>
3815 </restriction>
3816 </simpleType>
3817 ```
3818 </div>
3819
3820 🔝 [Back to table of contents](#)
3821
3822 Serialization rules {#rules}
3823 ===================
3824
3825 A presentation on XML data bindings is not complete without discussing the
3826 serialization rules and options that put your data in XML on the wire or store
3827 it a file or buffer.
3828
3829 There are several options to choose from to serialize data in XML. The choice
3830 depends on the use of the SOAP protocol or if SOAP is not required. The wsdl2h
3831 tool automates this for you by taking the WSDL transport bindings into account
3832 when generating the service functions in C and C++ that use SOAP or REST.
3833
3834 The gSOAP tools are not limited to SOAP. The tools implement generic XML data
3835 bindings for SOAP, REST, and other uses of XML. So you can read and write XML
3836 using the serializing [operations on classes and structs](#toxsd9-13).
3837
3838 The following sections briefly explain the serialization rules with respect to
3839 the SOAP protocol for XML Web services. A basic understanding of the SOAP
3840 protocol is useful when developing client and server applications that must
3841 interoperate with other SOAP applications.
3842
3843 SOAP/REST Web service client and service operations are represented as
3844 functions in your gSOAP header file with the data binding interface for
3845 soapcpp2. The soapcpp2 tool will translate these function to client-side
3846 service invocation calls and server-side service operation dispatchers.
3847
3848 A discussion of SOAP clients and servers is beyond the scope of this article.
3849 However, the SOAP options discussed here also apply to SOAP client and server
3850 development.
3851
3852 🔝 [Back to table of contents](#)
3853
3854 SOAP document versus rpc style {#doc-rpc}
3855 ------------------------------
3856
3857 The `wsdl:binding/soap:binding/@style` attribute in the `<wsdl:binding>`
3858 section of a WSDL is either "document" or "rpc". The "rpc" style refers to
3859 SOAP RPC (Remote Procedure Call), which is more restrictive than the "document"
3860 style by requiring one XML element in the SOAP Body to act as the procedure
3861 name with XML subelements as its parameters.
3862
3863 For example, the following directives in the gSOAP header file for soapcpp2
3864 declare that `DBupdate` is a SOAP RPC encoding service method:
3865
3866 ```cpp
3867 //gsoap ns service namespace: urn:DB
3868 //gsoap ns service method-protocol: DBupdate SOAP
3869 //gsoap ns service method-style: DBupdate rpc
3870 int ns__DBupdate(...);
3871 ```
3872
3873 The XML payload has a SOAP envelope, optional SOAP header, and a SOAP body with
3874 one element representing the operation with the parameters as subelements:
3875
3876 <div class="alt">
3877 ```xml
3878 <SOAP-ENV:Envelope
3879 xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
3880 xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
3881 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
3882 xmlns:xsd="http://www.w3.org/2001/XMLSchema"
3883 xmlsn:ns="urn:DB">
3884 <SOAP-ENV:Body>
3885 <ns:DBupdate>
3886 ...
3887 </ns:DBupdate>
3888 </SOAP-ENV:Body>
3889 </SOAP-ENV:Envelope>
3890 ```
3891 </div>
3892
3893 The "document" style puts no restrictions on the SOAP Body content. However, we
3894 recommend that the first element's tag name in the SOAP Body should be unique
3895 to each type of operation, so that the receiver can dispatch the operation
3896 based on this element's tag name. Alternatively, the HTTP URL path can be used
3897 to specify the operation, or the HTTP action header can be used to dispatch
3898 operations automatically on the server side (soapcpp2 options -a and -A).
3899
3900 🔝 [Back to table of contents](#)
3901
3902 SOAP literal versus encoding {#lit-enc}
3903 ----------------------------
3904
3905 The `wsdl:operation/soap:body/@use` attribute in the `<wsdl:binding>` section
3906 of a WSDL is either "literal" or "encoded". The "encoded" use refers to the
3907 SOAP encoding rules that support id-ref multi-referenced elements to serialize
3908 data as graphs.
3909
3910 SOAP encoding is very useful if the data internally forms a graph (including
3911 cycles) and we want the graph to be serialized in XML in a format that ensures
3912 that its structure is preserved. In that case, SOAP 1.2 encoding is the best
3913 option.
3914
3915 SOAP encoding also adds encoding rules for [SOAP arrays](#toxsd10) to serialize
3916 multi-dimensional arrays. The use of XML attributes to exchange XML data in
3917 SOAP encoding is not permitted. The only attributes permitted are the standard
3918 XSD attributes, SOAP encoding attributes (such as for arrays), and id-ref.
3919
3920 For example, the following directives in the gSOAP header file for soapcpp2
3921 declare that `DBupdate` is a SOAP RPC encoding service method:
3922
3923 ```cpp
3924 //gsoap ns service namespace: urn:DB
3925 //gsoap ns service method-protocol: DBupdate SOAP
3926 //gsoap ns service method-style: DBupdate rpc
3927 //gsoap ns service method-encoding: DBupdate encoded
3928 int ns__DBupdate(...);
3929 ```
3930
3931 The XML payload has a SOAP envelope, optional SOAP header, and a SOAP body with
3932 an encodingStyle attribute for SOAP 1.1 encoding and an element representing the
3933 operation with parameters that are SOAP 1.1 encoded:
3934
3935 <div class="alt">
3936 ```xml
3937 <SOAP-ENV:Envelope
3938 xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
3939 xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
3940 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
3941 xmlns:xsd="http://www.w3.org/2001/XMLSchema"
3942 xmlsn:ns="urn:DB">
3943 <SOAP-ENV:Body SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
3944 <ns:DBupdate>
3945 <records SOAP-ENC:arrayType="ns:record[3]">
3946 <item>
3947 <name href="#_1"/>
3948 <SSN>1234567890</SSN>
3949 </item>
3950 <item>
3951 <name>Jane</name>
3952 <SSN>1987654320</SSN>
3953 </item>
3954 <item>
3955 <name href="#_1"/>
3956 <SSN>2345678901</SSN>
3957 </item>
3958 </records>
3959 </ns:DBupdate>
3960 <id id="_1" xsi:type="xsd:string">Joe</id>
3961 </SOAP-ENV:Body>
3962 </SOAP-ENV:Envelope>
3963 ```
3964 </div>
3965
3966 Note that the name "Joe" is shared by two records and the string is referenced
3967 by SOAP 1.1 href and id attributes.
3968
3969 While gSOAP only introduces multi-referenced elements in the payload when they
3970 are actually multi-referenced in the data graph, other SOAP applications may
3971 render multi-referenced elements more aggressively. The example could also be
3972 rendered as:
3973
3974 <div class="alt">
3975 ```xml
3976 <SOAP-ENV:Envelope
3977 xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
3978 xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
3979 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
3980 xmlns:xsd="http://www.w3.org/2001/XMLSchema"
3981 xmlsn:ns="urn:DB">
3982 <SOAP-ENV:Body SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
3983 <ns:DBupdate>
3984 <records SOAP-ENC:arrayType="ns:record[3]">
3985 <item href="#id1"/>
3986 <item href="#id2"/>
3987 <item href="#id3"/>
3988 </records>
3989 </ns:DBupdate>
3990 <id id="id1" xsi:type="ns:record">
3991 <name href="#id4"/>
3992 <SSN>1234567890</SSN>
3993 </id>
3994 <id id="id2" xsi:type="ns:record">
3995 <name href="#id5"/>
3996 <SSN>1987654320</SSN>
3997 </id>
3998 <id id="id3" xsi:type="ns:record">
3999 <name href="#id4"/>
4000 <SSN>2345678901</SSN>
4001 </id>
4002 <id id="id4" xsi:type="xsd:string">Joe</id>
4003 <id id="id5" xsi:type="xsd:string">Jane</id>
4004 </SOAP-ENV:Body>
4005 </SOAP-ENV:Envelope>
4006 ```
4007 </div>
4008
4009 SOAP 1.2 encoding is cleaner and produces more accurate XML encodings of data
4010 graphs by setting the id attribute on the element that is referenced:
4011
4012 <div class="alt">
4013 ```xml
4014 <SOAP-ENV:Envelope
4015 xmlns:SOAP-ENV="http://www.w3.org/2003/05/soap-envelope"
4016 xmlns:SOAP-ENC="http://www.w3.org/2003/05/soap-encoding"
4017 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4018 xmlns:xsd="http://www.w3.org/2001/XMLSchema"
4019 xmlsn:ns="urn:DB">
4020 <SOAP-ENV:Body>
4021 <ns:DBupdate SOAP-ENV:encodingStyle="http://www.w3.org/2003/05/soap-encoding">
4022 <records SOAP-ENC:itemType="ns:record" SOAP-ENC:arraySize="3">
4023 <item>
4024 <name SOAP-ENC:id="_1">Joe</name>
4025 <SSN>1234567890</SSN>
4026 </item>
4027 <item>
4028 <name>Jane</name>
4029 <SSN>1987654320</SSN>
4030 </item>
4031 <item>
4032 <name SOAP-ENC:ref="_1"/>
4033 <SSN>2345678901</SSN>
4034 </item>
4035 </records>
4036 </ns:DBupdate>
4037 </SOAP-ENV:Body>
4038 </SOAP-ENV:Envelope>
4039 ```
4040 </div>
4041
4042 @note Some SOAP 1.2 applications consider the namespace `SOAP-ENC` of
4043 `SOAP-ENC:id` and `SOAP-ENC:ref` optional. The gSOAP SOAP 1.2 encoding
4044 serialization follows the 2007 standard, while accepting unqualified id and
4045 ref attributes.
4046
4047 To remove all rendered id-ref multi-referenced elements in gSOAP, use the
4048 `SOAP_XML_TREE` flag to initialize the gSOAP engine context.
4049
4050 Some XSD validation rules are turned off with SOAP encoding, because of the
4051 presence of additional attributes, such as id and ref/href, SOAP arrays with
4052 arbitrary element tags for array elements, and the occurrence of additional
4053 multi-ref elements in the SOAP 1.1 Body.
4054
4055 The use of "literal" puts no restrictions on the XML in the SOAP Body. Full
4056 XSD validation is possible, which can be enabled with the `SOAP_XML_STRICT`
4057 flag to initialize the gSOAP engine context. However, data graphs will be
4058 serialized as trees and cycles in the data will be cut from the XML rendition.
4059
4060 🔝 [Back to table of contents](#)
4061
4062 SOAP 1.1 versus SOAP 1.2 {#soap}
4063 ------------------------
4064
4065 There are two SOAP protocol versions: 1.1 and 1.2. The gSOAP tools can switch
4066 between the two versions seamlessly. You can declare the default SOAP version
4067 for a service operation as follows:
4068
4069 ```cpp
4070 //gsoap ns service method-protocol: DBupdate SOAP1.2
4071 ```
4072
4073 The gSOAP soapcpp2 auto-generates client and server code. At the client side,
4074 this operation sends data with SOAP 1.2 but accepts responses also in SOAP 1.1.
4075 At the server side, this operation accepts requests in SOAP 1.1 and 1.2 and
4076 will return responses in the same SOAP version.
4077
4078 As we discussed in the previous section, the SOAP 1.2 protocol has a cleaner
4079 multi-referenced element serialization format that greatly enhances the
4080 accuracy of data graph serialization with SOAP RPC encoding and is therefore
4081 recommended.
4082
4083 The SOAP 1.2 protocol default can also be set by importing and loading
4084 `gsoap/import/soap12.h`:
4085
4086 ```cpp
4087 #import "soap12.h"
4088 ```
4089
4090 🔝 [Back to table of contents](#)
4091
4092 Non-SOAP XML serialization {#non-soap}
4093 --------------------------
4094
4095 You can serialize data that is stored on the heap, on the stack (locals), and
4096 static data as long as the serializable (i.e. non-transient) members are
4097 properly initialized and pointers in the structures are either NULL or point to
4098 valid structures. Deserialized data is put on the heap and managed by the
4099 gSOAP engine context `struct soap`, see also [memory management](#memory).
4100
4101 You can read and write XML directly to a file or stream with the serializing
4102 [operations on classes and structs](#toxsd9-13).
4103
4104 To define and use XML Web service client and service operations, we can declare
4105 these operations in your gSOAP header file with the data binding interface for
4106 soapcpp2 as functions. The function are translated by soapcpp2 to client-side
4107 service invocation calls and server-side service operation dispatchers.
4108
4109 The REST operations POST, GET, and PUT are declared with `//gsoap` directives
4110 in the gSOAP header file for soapcpp2. For example, a REST POST operation is
4111 declared as follows:
4112
4113 ```cpp
4114 //gsoap ns service namespace: urn:DB
4115 //gsoap ns service method-protocol: DBupdate POST
4116 int ns__DBupdate(...);
4117 ```
4118
4119 There is no SOAP Envelope and no SOAP Body in the payload for `DBupdate`. Also
4120 the XML serialization rules are identical to SOAP document/literal. The XML
4121 payload only has the operation name as an element with its parameters
4122 serialized as subelements:
4123
4124 <div class="alt">
4125 ```xml
4126 <ns:DBupdate xmln:ns="urn:DB" ...>
4127 ...
4128 </ns:DBupdate>
4129 ```
4130 </div>
4131
4132 To force id-ref serialization with REST similar to SOAP 1.2 multi-reference
4133 encoding, use the `SOAP_XML_GRAPH` flag to initialize the gSOAP engine context.
4134 The XML serialization includes id and ref attributes for multi-referenced
4135 elements as follows:
4136
4137 <div class="alt">
4138 ```xml
4139 <ns:DBupdate xmln:ns="urn:DB" ...>
4140 <records>
4141 <item>
4142 <name id="_1">Joe</name>
4143 <SSN>1234567890</SSN>
4144 </item>
4145 <item>
4146 <name>Jane</name>
4147 <SSN>1987654320</SSN>
4148 </item>
4149 <item>
4150 <name ref="_1"/>
4151 <SSN>2345678901</SSN>
4152 </item>
4153 </records>
4154 </ns:DBupdate>
4155 ```
4156 </div>
4157
4158 🔝 [Back to table of contents](#)
4159
4160 Input and output {#io}
4161 ================
4162
4163 Reading and writing XML from/to files, streams and string buffers is done via
4164 the managing context by setting one of the following context members that
4165 control IO sources and sinks:
4166
4167 ```cpp
4168 soap->recvfd = fd; // an int file descriptor to read from (0 by default)
4169 soap->sendfd = fd; // an int file descriptor to write to (1 by default)
4170 soap->is = &is; // C++ only: a std::istream is object to read from
4171 soap->os = &os; // C++ only: a std::ostream os object to write to
4172 soap->is = cs; // C only: a const char* string to read from (soap->is will advance)
4173 soap->os = &cs; // C only: pointer to a const char*, will be set to point to the string output
4174 ```
4175
4176 Normally, all of these context members are NULL, which is required to send and
4177 receive data over sockets by gSOAP clients and servers. Therefore, if you set
4178 any of these context members in a client or server application then you MUST
4179 reset them to NULL to ensure that socket communications are not blocked.
4180
4181 Note: the use of `soap->is` and `soap->os` in C requires gSOAP 2.8.28 or later.
4182
4183 In the following sections, we present more details on how to read and write to
4184 files and streams, and use string buffers as sources and sinks for XML data.
4185
4186 In addition, you can set IO callback functions to handle IO at a lower level.
4187
4188 For more details, see the [gSOAP user guide.](http://www.genivia.com/doc/soapdoc2.html)
4189
4190 🔝 [Back to table of contents](#)
4191
4192 Reading and writing from/to files and streams {#io1}
4193 ---------------------------------------------
4194
4195 The default IO is standard input and output. Other sources and sinks (those
4196 listed above) will be used until you (re)set them. For example with file-based
4197 input and output:
4198
4199 ```cpp
4200 FILE *fp = fopen("record.xml", "r");
4201 if (fp != NULL)
4202 {
4203 soap->recvfd = fileno(fp); // get file descriptor of file to read from
4204 if (soap_read_ns__record(soap, &pers1))
4205 ... // handle IO error
4206 fclose(fp);
4207 soap->recvfd = 0; // read from stdin, or -1 to block reading
4208 }
4209
4210 FILE *fp = fopen("record.xml", "w");
4211 if (fp != NULL)
4212 {
4213 soap->sendfd = fileno(fp); // get file descriptor of file to write to
4214 if (soap_write_ns__record(soap, &pers1))
4215 ... // handle IO error
4216 fclose(fp);
4217 soap->sendfd = 1; // write to stdout, or -1 to block writing
4218 }
4219 ```
4220
4221 Similar code with streams in C++:
4222
4223 ```cpp
4224 #include <fstream>
4225
4226 std::fstream fs;
4227 fs.open("record.xml", std::ios::in);
4228 if (fs)
4229 {
4230 soap->is = &fs;
4231 if (soap_read__ns__record(soap, &pers1))
4232 ... // handle IO error
4233 fs.close();
4234 soap->is = NULL;
4235 }
4236
4237 fs.open("record.xml", std::ios::out);
4238 if (fs)
4239 {
4240 soap->os = &fs;
4241 if (soap_write__ns__record(soap, &pers1))
4242 ... // handle IO error
4243 fs.close();
4244 soap->os = NULL;
4245 }
4246 ```
4247
4248 🔝 [Back to table of contents](#)
4249
4250 Reading and writing from/to string buffers {#io2}
4251 ------------------------------------------
4252
4253 For C++ we recommend to use `std::stringstream` objects from `<sstream>` as
4254 illustrated in the following example:
4255
4256 ```cpp
4257 #include <sstream>
4258
4259 std::stringstream ss;
4260 ss.str("..."); // XML to parse
4261 soap->is = &ss;
4262 if (soap_read__ns__record(soap, &pers1))
4263 ... // handle IO error
4264 soap->is = NULL;
4265
4266 soap->os = &ss;
4267 if (soap_write__ns__record(soap, &pers1))
4268 ... // handle IO error
4269 soap->os = NULL;
4270 std::string s = ss.str(); // string with XML
4271 ```
4272
4273 For C we can use `soap->is` and `soap->os` to point to strings of XML content
4274 as follows (this requires gSOAP 2.8.28 or later):
4275
4276 ```cpp
4277 soap->is = "..."; // XML to parse
4278 if (soap_read__ns__record(soap, &pers1))
4279 ... // handle IO error
4280 soap->is = NULL;
4281
4282 const char *cs = NULL;
4283 soap->os = &cs;
4284 if (soap_write__ns__record(soap, &pers1))
4285 ... // handle IO error
4286 soap->os = NULL;
4287 ... = cs; // string with XML (do not free(cs): managed by the context and freed with soap_end())
4288 ```
4289
4290 Note that `soap->os` is a pointer to a `const char*` string. The pointer is
4291 set by the managing context to point to the XML data that is stored on the
4292 context-managed heap.
4293
4294 For earlier gSOAP versions we recommend to use IO callbacks `soap->frecv` and
4295 `soap->fsend`, see the [gSOAP user guide.](http://www.genivia.com/doc/soapdoc2.html)
4296
4297 🔝 [Back to table of contents](#)
4298
4299 Memory management {#memory}
4300 =================
4301
4302 Memory management with the `soap` context enables us to allocate data in
4303 context-managed heap space that can be collectively deleted. All deserialized
4304 data is placed on the context-managed heap by the gSOAP engine.
4305
4306 🔝 [Back to table of contents](#)
4307
4308 Memory management in C {#memory1}
4309 ----------------------
4310
4311 When working with gSOAP in C (i.e. using wsdl2h option `-c` and soapcpp2 option
4312 `-c`), data is allocated on the managed heap with:
4313
4314 - `void *soap_malloc(struct soap*, size_t len)`.
4315
4316 You can also make shallow copies of data with `soap_memdup` that uses
4317 `soap_malloc` and a safe version of `memcpy` to copy a chunk of data `src` with
4318 length `len` to the context-managed heap:
4319
4320 - `void * soap_memdup(struct soap*, const void *src, size_t len)`
4321
4322 This function returns a pointer to the copy. This function requires gSOAP
4323 2.8.27 or later.
4324
4325 In gSOAP 2.8.35 and later, you can use an auto-generated function to allocate
4326 and initialize data of type `T` on the managed heap:
4327
4328 - `T * soap_new_T(struct soap*, int n)`
4329
4330 This function returns an array of length `n` of type `T` data that is default
4331 initialized (by internally calling `soap_malloc(soap, n * sizeof(T))` and then
4332 `soap_default_T(soap, T*)` on each array value). Use `n=1` to allocate and
4333 initialize a single value.
4334
4335 The `soap_malloc` function is a wrapper around `malloc`, but which also permits
4336 the `struct soap` context to track all heap allocations for collective deletion
4337 with `soap_end(soap)`:
4338
4339 ```cpp
4340 #include "soapH.h"
4341 #include "ns.nsmap"
4342 ...
4343 struct soap *soap = soap_new(); // new context
4344 ...
4345 struct ns__record *record = (struct ns__record*)soap_malloc(soap, sizeof(struct ns__record));
4346 soap_default_ns__record(soap, record); // auto-generated struct initializer
4347 ...
4348 soap_destroy(soap); // only for C++, see section on C++ below
4349 soap_end(soap); // delete record and all other heap allocations
4350 soap_free(soap); // delete context
4351 ```
4352
4353 All data on the managed heap is mass-deleted with `soap_end(soap)` which must
4354 be called before `soap_done(soap)` or `soap_free(soap)`, which end the use of
4355 the `soap` engine context and free the context, respectively. Use
4356 `soap_free(soap)` only when the context is allocated with `soap_new()`. Use
4357 `soap_done(soap)` only when the context is stack allocated (so cannot be
4358 deleted from the heap).
4359
4360 The managed heap is checked for memory leaks when the gSOAP code is compiled
4361 with `-DDEBUG`.
4362
4363 The soapcpp2 auto-generated deserializers in C use `soap_malloc` to allocate
4364 and populate deserialized structures, which are managed by the context for
4365 collective deletion.
4366
4367 To make `char*` and `wchar_t*` string copies to the context-managed heap, we
4368 can use the functions:
4369
4370 - `char *soap_strdup(struct soap*, const char *str)` and
4371 - `wchar_t *soap_wstrdup(struct soap*, const wchar_t *wstr)`.
4372
4373 If your C compiler supports `typeof` then you can use the following macro to
4374 simplify the managed heap allocation and initialization of primitive values:
4375
4376 ```cpp
4377 #define soap_assign(soap, lhs, rhs) (*(lhs = (typeof(lhs))soap_malloc(soap, sizeof(*lhs))) = rhs)
4378 ```
4379
4380 Pointers to primitive values are often used for optional members. For example,
4381 assume we have the following struct:
4382
4383 ```cpp
4384 struct ns__record
4385 {
4386 const char *name 1; // required (minOccurs=1)
4387 uint64_t *SSN; // optional (pointer means minOccurs=0)
4388 struct ns__record *spouse; // optional (pointer means minOccurs=0)
4389 };
4390 ```
4391
4392 Use `soap_assign` to create a SSN value on the managed heap:
4393
4394 ```cpp
4395 struct soap *soap = soap_new(); // new context
4396 ...
4397 struct ns__record *record = (struct ns__record*)soap_malloc(soap, sizeof(struct ns__record));
4398 soap_default_ns__record(soap, record);
4399 record->name = soap_strdup(soap, "Joe");
4400 soap_assign(soap, record->SSN, 1234567890UL);
4401 ...
4402 soap_end(soap); // delete managed soap_malloc'ed heap data
4403 soap_free(soap); // delete context
4404 ```
4405
4406 Without the `soap_assign` macro, you will need two lines of code, one to
4407 allocate and one to assign (you should also use this if your system can run out
4408 of memory):
4409
4410 ```cpp
4411 assert((record->SSN = (uint64_t*)soap_malloc(soap, sizeof(utint64_t))) != NULL);
4412 *record->SSN = 1234567890UL;
4413 ```
4414
4415 The gSOAP serializer can serialize any heap, stack, or static allocated data.
4416 So we can also create a new record as follows:
4417
4418 ```cpp
4419 struct soap *soap = soap_new(); // new context
4420 ...
4421 struct ns__record *record = (struct ns__record*)soap_malloc(soap, sizeof(struct ns__record));
4422 static uint64_t SSN = 1234567890UL;
4423 soap_default_ns__record(soap, record);
4424 record->name = "Joe";
4425 record->SSN = &SSN; // safe to use static values: the value of record->SSN is never changed by gSOAP
4426 ...
4427 soap_end(soap); // delete managed soap_malloc'ed heap data
4428 soap_free(soap); // delete context
4429 ```
4430
4431 Use the soapcpp2 auto-generated `soap_dup_T` functions to duplicate data into
4432 another context (this requires soapcpp2 option `-Ec` to generate), here shown
4433 for C with the second argument `dst` NULL because we want to allocate a new
4434 managed structure:
4435
4436 ```cpp
4437 struct soap *other_soap = soap_new(); // another context
4438 struct ns__record *other_record = soap_dup_ns__record(other_soap, NULL, record);
4439 ...
4440 soap_destroy(other_soap); // only for C++, see section on C++ below
4441 soap_end(other_soap); // delete other_record and all of its deep data
4442 soap_free(other_soap); // delete context
4443 ```
4444
4445 Note that the only reason to use another context and not to use the primary
4446 context is when the primary context must be destroyed together with all of the
4447 objects it manages while some of the objects must be kept alive. If the objects
4448 that are kept alive contain deep cycles then this is the only option we have,
4449 because deep copy with a managing context detects and preserves these
4450 cycles unless the `SOAP_XML_TREE` flag is used with the context:
4451
4452 ```cpp
4453 struct soap *other_soap = soap_new1(SOAP_XML_TREE); // another context
4454 struct ns__record *other_record = soap_dup_ns__record(other_soap, NULL, record);
4455 ```
4456
4457 The resulting deep copy will be a full copy of the source data structure as a
4458 tree without co-referenced data (i.e. no digraph) and without cycles. Cycles
4459 are pruned and (one of the) pointers that forms a cycle is repaced by NULL.
4460
4461 You can also deep copy into unmanaged space and use the auto-generated
4462 `soap_del_T()` function (requires soapcpp2 option `-Ed` to generate) to delete
4463 it later, but you MUST NOT do this for any data that has deep cycles in its
4464 runtime data structure:
4465
4466 ```cpp
4467 struct ns__record *other_record = soap_dup_ns__record(NULL, NULL, record);
4468 ...
4469 soap_del_ns__record(other_record); // deep delete record data members
4470 free(other_record); // delete the record
4471 ```
4472
4473 Cycles in the data structure will lead to non-termination when making unmanaged
4474 deep copies. Consider for example:
4475
4476 ```cpp
4477 struct ns__record
4478 {
4479 const char *name 1; // required (minOccurs=1)
4480 uint64_t SSN; // required (non-pointer means minOccurs=1)
4481 struct ns__record *spouse; // optional (pointer means minOccurs=0)
4482 };
4483 ```
4484
4485 The code to populate a structure with a mutual spouse relationship:
4486
4487 ```cpp
4488 struct soap *soap = soap_new();
4489 ...
4490 struct ns__record pers1, pers2;
4491 soap_default_ns__record(soap, &pers1);
4492 soap_default_ns__record(soap, &pers2);
4493 pers1.name = "Joe"; // OK to serialize static data
4494 pers1.SSN = 1234567890;
4495 pers1.spouse = &pers2;
4496 pers2.name = soap_strdup(soap, "Jane"); // allocates and copies a string
4497 pers2.SSN = 1987654320;
4498 pers2.spouse = &pers1;
4499 ...
4500 struct ns__record *pers3 = soap_dup_ns__record(NULL, NULL, &pers1); // BAD
4501 struct ns__record *pers4 = soap_dup_ns__record(soap, NULL, &pers1); // OK
4502 soap_set_mode(soap, SOAP_XML_TREE);
4503 struct ns__record *pers5 = soap_dup_ns__record(soap, NULL, &pers1); // OK
4504 ```
4505
4506 As we can see, the gSOAP serializer can serialize any heap, stack, or static
4507 allocated data, such as in the code above. So we can serialize the
4508 stack-allocated `pers1` record as follows:
4509
4510 ```cpp
4511 FILE *fp = fopen("record.xml", "w");
4512 if (fp != NULL)
4513 {
4514 soap->sendfd = fileno(fp); // file descriptor to write to
4515 soap_set_mode(soap, SOAP_XML_GRAPH); // support id-ref w/o requiring SOAP
4516 soap_clr_mode(soap, SOAP_XML_TREE); // if set, clear
4517 soap_write_ns__record(soap, &pers1);
4518 fclose(fp);
4519 soap->sendfd = -1; // block further writing
4520 }
4521 ```
4522
4523 which produces an XML document record.xml that is similar to:
4524
4525 <div class="alt">
4526 ```xml
4527 <ns:record xmlns:ns="urn:types" id="Joe">
4528 <name>Joe</name>
4529 <SSN>1234567890</SSN>
4530 <spouse id="Jane">
4531 <name>Jane</name>
4532 <SSN>1987654320</SSN>
4533 <spouse ref="#Joe"/>
4534 </spouse>
4535 </ns:record>
4536 ```
4537 </div>
4538
4539 Deserialization of an XML document with a SOAP 1.1/1.2 encoded id-ref graph
4540 leads to the same non-termination problem when we later try to copy the data
4541 into unmanaged memory heap space:
4542
4543 ```cpp
4544 struct soap *soap = soap_new1(SOAP_XML_GRAPH); // support id-ref w/o SOAP
4545 ...
4546 struct ns__record pers1;
4547 FILE *fp = fopen("record.xml", "r");
4548 if (fp != NULL)
4549 {
4550 soap->recvfd = fileno(fp);
4551 if (soap_read_ns__record(soap, &pers1))
4552 ... // handle IO error
4553 fclose(fp);
4554 soap->recvfd = -1; // blocks further reading
4555 }
4556 ...
4557 struct ns__record *pers3 = soap_dup_ns__record(NULL, NULL, &pers1); // BAD
4558 struct ns__record *pers4 = soap_dup_ns__record(soap, NULL, &pers1); // OK
4559 soap_set_mode(soap, SOAP_XML_TREE);
4560 struct ns__record *pers5 = soap_dup_ns__record(soap, NULL, &pers1); // OK
4561 ```
4562
4563 Copying data with `soap_dup_T(soap)` into managed heap memory space is always
4564 safe. Copying into unmanaged heap memory space requires diligence. But
4565 deleting unmanaged data is easy with `soap_del_T()`.
4566
4567 You can also use `soap_del_T()` to delete structures that you created in C, but
4568 only if these structures are created with `malloc` and do NOT contain pointers
4569 to stack and static data.
4570
4571 You can unlink one or more allocated objects from the managed heap to allow the
4572 object to live after `soap_end(soap)` by using:
4573
4574 - `void soap_unlink(struct soap *soap, void *ptr)`
4575
4576 The unlinked heap-allocated data pointed to by `ptr` can be accessed after
4577 `soap_end(soap)`. Do not forget to free the data with `free(ptr)`. Be aware
4578 that `soap_unlink(soap, ptr)` does not perform a deep unlinkage. If `ptr` is a
4579 struct, pointer members will become invalid when pointing to objects on the
4580 managed heap. Use `soap_unlink(soap, ptr->member)` to unlink `member` as well.
4581
4582 Finally, when data is allocated in managed memory heap space, either explicitly
4583 with the allocation functions shown above or by the gSOAP deserializers, you
4584 can delegate the management and deletion of this data to another `struct soap`
4585 context. That context will be responsible to delete the data with
4586 `soap_end(soap)` later:
4587
4588 - `void delegate_deletion(struct soap *soap_from, struct soap *soap_to)`
4589
4590 This allows the `soap_from` context to be deleted with `soap_free(soap_from)`
4591 (assuming it is allocated with `soap_new()`, use `soap_done(soap_from)` when
4592 `soap_from` is stack-allocated) while the managed data remains intact. You
4593 can use this function any time, to delegate management and deletion to another
4594 context `soap_to` and then continue with the current context. You can also use
4595 different source `soap_from` contexts to delegate management and deletion to
4596 the other `soap_to` context. To mass delete all managed data, use
4597 `soap_end(soap_to)`.
4598
4599 🔝 [Back to table of contents](#)
4600
4601 Memory management in C++ {#memory2}
4602 ------------------------
4603
4604 When working with gSOAP in C++, the gSOAP engine allocates data on a managed
4605 heap using `soap_new_T(soap)` to allocate a type with type name `T`. Managed
4606 heap allocation is tracked by the `struct soap` context for collective deletion
4607 with `soap_destroy(soap)` for structs, classes, and templates and with
4608 `soap_end(soap)` for everything else.
4609
4610 You should only use `soap_malloc(struct soap*, size_t len)` to allocate
4611 primitive types, but `soap_new_T()` is preferred. The auto-generated `T *
4612 soap_new_T(struct soap*)` returns data allocated on the managed heap for type
4613 `T`. The data is mass-deleted with `soap_destroy(soap)` followed by
4614 `soap_end(soap)`.
4615
4616 The `soap_new_T` functions return NULL when allocation fails. C++ exceptions
4617 are never raised by gSOAP code when data is allocated, unless `SOAP_NOTHROW`
4618 (set to `(std::nothrow)`) is redefined to permit `new` to throw exceptions.
4619
4620 There are four variations of `soap_new_T()` to allocate data of type `T` that
4621 soapcpp2 auto-generates:
4622
4623 - `T * soap_new_T(struct soap*)` returns a new instance of `T` that is default
4624 initialized. For classes, initialization is internally performed using the
4625 soapcpp2 auto-generated `void T::soap_default(struct soap*)` method of the
4626 class, but ONLY IF the soapcpp2 auto-generated default constructor is used
4627 that invokes `soap_default()` and was not replaced by a user-defined default
4628 constructor.
4629
4630 - `T * soap_new_T(struct soap*, int n)` returns an array of `n` new instances of
4631 `T`. The instances in the array are default initialized as described above.
4632
4633 - `T * soap_new_req_T(struct soap*, ...)` (structs and classes only) returns a
4634 new instance of `T` and sets the required data members to the values
4635 specified in `...`. The required data members are those with nonzero
4636 minOccurs, see the subsections on
4637 [(smart) pointer members and their occurrence constraints](#toxsd9-8) and
4638 [container and array members and their occurrence constraints](#toxsd9-9).
4639
4640 - `T * soap_new_set_T(struct soap*, ...)` (structs and classes only) returns a
4641 new instance of `T` and sets the public/serializable data members to the values
4642 specified in `...`.
4643
4644 The above functions can be invoked with a NULL `soap` context, but you are then
4645 responsible to use `delete T` to remove this instance from the unmanaged heap.
4646
4647 For example, to allocate a managed `std::string` you can use:
4648
4649 ```cpp
4650 std::string *s = soap_new_std__string(soap);
4651 ```
4652
4653 Primitive types and arrays of these are allocated with `soap_malloc`
4654 (`soap_new_T` calls `soap_malloc` for primitive type `T`). All primitive types
4655 (i.e. no classes, structs, class templates, containers, and smart pointers) are
4656 allocated with `soap_malloc` for reasons of efficiency.
4657
4658 You can use a C++ template to simplify the managed allocation and initialization
4659 of primitive values as follows (this is for primitive types only):
4660
4661 ```cpp
4662 template<class T>
4663 T * soap_make(struct soap *soap, T val) throw (std::bad_alloc)
4664 {
4665 T *p = (T*)soap_malloc(soap, sizeof(T));
4666 if (p == NULL)
4667 throw std::bad_alloc();
4668 *p = val;
4669 return p;
4670 }
4671 ```
4672
4673 For example, assuming we have the following class:
4674
4675 ```cpp
4676 class ns__record
4677 {
4678 public:
4679 std::string name; // required (non-pointer means minOccurs=1)
4680 uint64_t *SSN; // optional (pointer means minOccurs=0)
4681 ns__record *spouse; // optional (pointer means minOccurs=0)
4682 };
4683 ```
4684
4685 You can instantiate a record by using the auto-generated
4686 `soap_new_set_ns__record` and use `soap_make` to create a SSN value on the
4687 managed heap as follows:
4688
4689 ```cpp
4690 soap *soap = soap_new(); // new context
4691 ...
4692 ns__record *record = soap_new_set_ns__record(
4693 soap,
4694 "Joe",
4695 soap_make<uint64_t>(soap, 1234567890UL),
4696 NULL);
4697 ...
4698 soap_destroy(soap); // delete record and all other managed instances
4699 soap_end(soap); // delete managed soap_malloc'ed heap data
4700 soap_free(soap); // delete context
4701 ```
4702
4703 All data on the managed heap is mass-deleted with `soap_end(soap)` which must
4704 be called before `soap_done(soap)` or `soap_free(soap)`, which end the use of
4705 the `soap` engine context and free the context, respectively. Use
4706 `soap_free(soap)` only when the context is allocated with `soap_new()`. Use
4707 `soap_done(soap)` only when the context is stack allocated (so cannot be
4708 deleted from the heap).
4709
4710 The managed heap is checked for memory leaks when the gSOAP code is compiled
4711 with `-DDEBUG`.
4712
4713 Note however that the gSOAP serializer can serialize any heap, stack, or static
4714 allocated data. So we can also create a new record as follows:
4715
4716 ```cpp
4717 uint64_t SSN = 1234567890UL;
4718 ns__record *record = soap_new_set_ns__record(soap, "Joe", &SSN, NULL);
4719 ```
4720
4721 which will be fine to serialize this record as long as the local `SSN`
4722 stack-allocated value remains in scope when invoking the serializer and/or
4723 using `record`. It does not matter if `soap_destroy` and `soap_end` are called
4724 beyond the scope of `SSN`.
4725
4726 To facilitate class methods to access the managing context, we can add a soap
4727 context pointer to a class/struct:
4728
4729 ```cpp
4730 class ns__record
4731 {
4732 ...
4733 void create_more(); // needs a context to create more internal data
4734 protected:
4735 struct soap *soap; // the context that manages this instance, or NULL
4736 };
4737 ```
4738
4739 The context is set when invoking `soap_new_T` (and similar) with a non-NULL
4740 context argument.
4741
4742 You can also use a template when an array of pointers to values is required.
4743 To create an array of pointers to values, define the following template:
4744
4745 ```cpp
4746 template<class T>
4747 T **soap_make_array(struct soap *soap, T* array, int n) throw (std::bad_alloc)
4748 {
4749 T **p = (T**)soap_malloc(soap, n * sizeof(T*));
4750 if (p == NULL)
4751 throw std::bad_alloc();
4752 for (int i = 0; i < n; ++i)
4753 p[i] = &array[i];
4754 return p;
4755 }
4756 ```
4757
4758 The `array` parameter is a pointer to an array of `n` values. The template
4759 returns an array of `n` pointers that point to the values in that array:
4760
4761 ```cpp
4762 // create an array of 100 pointers to 100 records
4763 int n = 100;
4764 ns__record **precords = soap_make_array(soap, soap_new_ns__record(soap, n), n);
4765 for (int i = 0; i < n; ++i)
4766 {
4767 precords[i]->name = "...";
4768 precords[i]->SSN = soap_make<uint64_t>(1234567890UL + i);
4769 }
4770 ```
4771
4772 Note that `soap_new_ns__record(soap, n)` returns a pointer to an array of `n`
4773 records, which is then used to create an array of `n` pointers to these records.
4774
4775 Use the soapcpp2 auto-generated `soap_dup_T` functions to duplicate data into
4776 another context (this requires soapcpp2 option `-Ec` to generate), here shown
4777 for C++ with the second argument `dst` NULL to allocate a new managed object:
4778
4779 ```cpp
4780 soap *other_soap = soap_new(); // another context
4781 ns__record *other_record = soap_dup_ns__record(other_soap, NULL, record);
4782 ...
4783 soap_destroy(other_soap); // delete record and other managed instances
4784 soap_end(other_soap); // delete other data (the SSNs on the heap)
4785 soap_free(other_soap); // delete context
4786 ```
4787
4788 To duplicate base and derived instances when a base class pointer or reference
4789 is provided, use the auto-generated method `T * T::soap_dup(struct soap*)`:
4790
4791 ```cpp
4792 soap *other_soap = soap_new(); // another context
4793 ns__record *other_record = record->soap_dup(other_soap);
4794 ...
4795 soap_destroy(other_soap); // delete record and other managed instances
4796 soap_end(other_soap); // delete other data (the SSNs on the heap)
4797 soap_free(other_soap); // delete context
4798 ```
4799
4800 Note that the only reason to use another context and not to use the primary
4801 context is when the primary context must be destroyed together with all of the
4802 objects it manages while some of the objects must be kept alive. If the objects
4803 that are kept alive contain deep cycles then this is the only option we have,
4804 because deep copy with a managing context detects and preserves these
4805 cycles unless the `SOAP_XML_TREE` flag is used with the context:
4806
4807 ```cpp
4808 soap *other_soap = soap_new1(SOAP_XML_TREE); // another context
4809 ns__record *other_record = record->soap_dup(other_soap); // deep tree copy
4810 ```
4811
4812 The resulting deep copy will be a full copy of the source data structure as a
4813 tree without co-referenced data (i.e. no digraph) and without cycles. Cycles
4814 are pruned and (one of the) pointers that forms a cycle is repaced by NULL.
4815
4816 You can also deep copy into unmanaged space and use the auto-generated
4817 `soap_del_T()` function or the `T::soap_del()` method (requires soapcpp2 option
4818 `-Ed` to generate) to delete it later, but we MUST NOT do this for any data
4819 that has deep cycles in its runtime data structure graph:
4820
4821 ```cpp
4822 ns__record *other_record = record->soap_dup(NULL);
4823 ...
4824 other_record->soap_del(); // deep delete record data members
4825 delete other_record; // delete the record
4826 ```
4827
4828 Cycles in the data structure will lead to non-termination when making unmanaged
4829 deep copies. Consider for example:
4830
4831 ```cpp
4832 class ns__record
4833 {
4834 const char *name 1; // required (minOccurs=1)
4835 uint64_t SSN; // required (non-pointer means minOccurs=1)
4836 ns__record *spouse; // optional (pointer means minOccurs=1)
4837 };
4838 ```
4839
4840 The code to populate a structure with a mutual spouse relationship:
4841
4842 ```cpp
4843 soap *soap = soap_new();
4844 ...
4845 ns__record pers1, pers2;
4846 pers1.name = "Joe";
4847 pers1.SSN = 1234567890;
4848 pers1.spouse = &pers2;
4849 pers2.name = "Jane";
4850 pers2.SSN = 1987654320;
4851 pers2.spouse = &pers1;
4852 ...
4853 ns__record *pers3 = soap_dup_ns__record(NULL, NULL, &pers1); // BAD
4854 ns__record *pers4 = soap_dup_ns__record(soap, NULL, &pers1); // OK
4855 soap_set_mode(soap, SOAP_XML_TREE);
4856 ns__record *pers5 = soap_dup_ns__record(soap, NULL, &pers1); // OK
4857 ```
4858
4859 Note that the gSOAP serializer can serialize any heap, stack, or static
4860 allocated data, such as in the code above. So we can serialize the
4861 stack-allocated `pers1` record as follows:
4862
4863 ```cpp
4864 FILE *fp = fopen("record.xml", "w");
4865 if (fp != NULL)
4866 {
4867 soap->sendfd = fileno(fp); // file descriptor to write to
4868 soap_set_mode(soap, SOAP_XML_GRAPH); // support id-ref w/o requiring SOAP
4869 soap_clr_mode(soap, SOAP_XML_TREE); // if set, clear
4870 if (soap_write_ns__record(soap, &pers1))
4871 ... // handle IO error
4872 fclose(fp);
4873 soap->sendfd = -1; // block further writing
4874 }
4875 ```
4876
4877 which produces an XML document record.xml that is similar to:
4878
4879 <div class="alt">
4880 ```xml
4881 <ns:record xmlns:ns="urn:types" id="Joe">
4882 <name>Joe</name>
4883 <SSN>1234567890</SSN>
4884 <spouse id="Jane">
4885 <name>Jane</name>
4886 <SSN>1987654320</SSN>
4887 <spouse ref="#Joe"/>
4888 </spouse>
4889 </ns:record>
4890 ```
4891 </div>
4892
4893 Deserialization of an XML document with a SOAP 1.1/1.2 encoded id-ref graph
4894 leads to the same non-termination problem when we later try to copy the data
4895 into unmanaged space:
4896
4897 ```cpp
4898 soap *soap = soap_new1(SOAP_XML_GRAPH); // support id-ref w/o SOAP
4899 ...
4900 ns__record pers1;
4901 FILE *fp = fopen("record.xml", "r");
4902 if (fp != NULL)
4903 {
4904 soap->recvfd = fileno(fp); // file descriptor to read from
4905 if (soap_read_ns__record(soap, &pers1))
4906 ... // handle IO error
4907 fclose(fp);
4908 soap->recvfd = -1; // block further reading
4909 }
4910 ...
4911 ns__record *pers3 = soap_dup_ns__record(NULL, NULL, &pers1); // BAD
4912 ns__record *pers4 = soap_dup_ns__record(soap, NULL, &pers1); // OK
4913 soap_set_mode(soap, SOAP_XML_TREE);
4914 ns__record *pers5 = soap_dup_ns__record(soap, NULL, &pers1); // OK
4915 ```
4916
4917 Copying data with `soap_dup_T(soap)` into managed space is always safe. Copying
4918 into unmanaged space requires diligence. But deleting unmanaged data is easy
4919 with `soap_del_T()`.
4920
4921 You can also use `soap_del_T()` to delete structures in C++, but only if these
4922 structures are created with `new` (and `new []` for arrays when applicable) for
4923 classes, structs, and class templates and with `malloc` for anything else, and
4924 the structures do NOT contain pointers to stack and static data.
4925
4926 You can unlink one or more allocated objects from the managed heap to allow the
4927 object to live after `soap_destroy(soap)` and `soap_end(soap)` by using:
4928
4929 - `void soap_unlink(struct soap *soap, void *ptr)`
4930
4931 The unlinked heap-allocated data pointed to by `ptr` can be accessed after
4932 `soap_destroy(soap)` and `soap_end(soap)`. Do not forget to free the data with
4933 `delete ptr` (C++ class instance only) or with `free(ptr)` (non-class data).
4934 Be aware that `soap_unlink(soap, ptr)` does not perform a deep unlinkage. If
4935 `ptr` is a struct or class, pointer members will become invalid when pointing
4936 to objects on the managed heap. Use `soap_unlink(soap, ptr->member)` to unlink
4937 `member` as well.
4938
4939 Finally, when data is allocated in managed memory heap space, either explicitly
4940 with the allocation functions shown above or by the gSOAP deserializers, you
4941 can delegate the management and deletion of this data to another `struct soap`
4942 context. That context will be responsible to delete the data with
4943 `soap_destroy(soap)` and `soap_end(soap)` later:
4944
4945 - `void delegate_deletion(struct soap *soap_from, struct soap *soap_to)`
4946
4947 This allows the `soap_from` context to be deleted with `soap_free(soap_from)`
4948 (assuming it is allocated with `soap_new()`, use `soap_done(soap_from)` when
4949 `soap_from` is stack-allocated) while the managed data remains intact. You
4950 can use this function any time, to delegate management and deletion to another
4951 context `soap_to` and then continue with the current context. You can also use
4952 different source `soap_from` contexts to delegate management and deletion to
4953 the other `soap_to` context. To mass delete all managed data, use
4954 `soap_destroy(soap_to)` followed by `soap_end(soap_to)`.
4955
4956 🔝 [Back to table of contents](#)
4957
4958 Context flags to initialize the soap struct {#flags}
4959 ===========================================
4960
4961 There are several context initialization flags and context mode flags to
4962 control XML serialization at runtime. The flags are set with `soap_new1()` to
4963 allocate and initialize a new context:
4964
4965 ```cpp
4966 struct soap *soap = soap_new1(<flag> | <flag> ... | <flag>);
4967 ...
4968 soap_destroy(soap); // delete objects
4969 soap_end(soap); // delete other data and temp data
4970 soap_free(soap); // free context
4971 ```
4972
4973 and with `soap_init1()` for stack-allocated contexts:
4974
4975 ```cpp
4976 struct soap soap;
4977 soap_init1(&soap, <flag> | <flag> ... | <flag>);
4978 ...
4979 soap_destroy(&soap); // delete objects
4980 soap_end(&soap); // delete other data and temp data
4981 soap_done(&soap); // clear context
4982 ```
4983
4984 where `<flag>` is one of:
4985
4986 - `SOAP_C_UTFSTRING`: enables all `std::string` and `char*` strings to
4987 contain UTF-8 content. This option is recommended.
4988
4989 - `SOAP_C_NILSTRING`: treat empty strings as if they were NULL pointers, i.e.
4990 omits elements and attributes when empty.
4991
4992 - `SOAP_XML_STRICT`: strictly validates XML while deserializing. Should not be
4993 used together with SOAP 1.1/1.2 encoding style of messaging. Use soapcpp2
4994 option `-s` to hard code `SOAP_XML_STRICT` in the generated serializers. Not
4995 recommended with SOAP 1.1/1.2 encoding style messaging.
4996
4997 - `SOAP_XML_INDENT`: produces indented XML.
4998
4999 - `SOAP_XML_CANONICAL`: c14n canonocalization, removes unused `xmlns` bindings
5000 and adds them to appropriate places by applying c14n normalization rules.
5001 Should not be used together with SOAP 1.1/1.2 encoding style messaging.
5002
5003 - `SOAP_XML_TREE`: write tree XML without id-ref, while pruning data structure
5004 cycles to prevent nontermination of the serializer for cyclic structures.
5005
5006 - `SOAP_XML_GRAPH`: write graph (digraph and cyclic graphs with shared pointers
5007 to objects) using id-ref attributes. That is, XML with SOAP multi-ref
5008 encoded id-ref elements. This is a structure-preserving serialization format,
5009 because co-referenced data and also cyclic relations are accurately represented.
5010
5011 - `SOAP_XML_DEFAULTNS`: uses xmlns default namespace declarations, assuming
5012 that the schema attribute form is "qualified" by default (be warned if it is
5013 not, since attributes in the null namespace will get bound to namespaces!).
5014
5015 - `SOAP_XML_NIL`: emit empty element with `xsi:nil` for all NULL pointers
5016 serialized.
5017
5018 - `SOAP_XML_IGNORENS`: the XML parser ignores XML namespaces, i.e. element and
5019 attribute tag names match independent of their namespace.
5020
5021 - `SOAP_XML_NOTYPE`: removes all `xsi:type` attribuation. This option is usually
5022 not needed unless the receiver rejects all `xsi:type` attributes. This option
5023 may affect the quality of the deserializer, which relies on `xsi:type`
5024 attributes to distinguish base class instances from derived class instances
5025 transported in the XML payloads.
5026
5027 - `SOAP_IO_CHUNK`: to enable HTTP chunked transfers.
5028
5029 - `SOAP_IO_STORE`: full buffering of outbound messages.
5030
5031 - `SOAP_ENC_ZLIB`: compress messages, requires compiling with `-DWITH_GZIP` and
5032 linking with zlib (`-lz`).
5033
5034 - `SOAP_ENC_MIME`: enable MIME attachments, see
5035 [MIME/MTOM attachment binary types](#toxsd10-3).
5036
5037 - `SOAP_ENC_MTOM`: enable MTOM attachments, see
5038 [MIME/MTOM attachment binary types](#toxsd10-3).
5039
5040 @note C++ Web service proxy and service classes have their own context, either
5041 as a base class (soapcpp2 option -i) or as a data member `soap` that points to
5042 a context (soapcpp2 option -j). These contexts are allocated when the proxy or
5043 service is instantiated with context flags that are passed to the constructor.
5044
5045 🔝 [Back to table of contents](#)
5046
5047 Context parameter settings {#params}
5048 ==========================
5049
5050 After allocation and initializtion of a `struct soap` context, several context
5051 parameters can be set (some parameters may require 2.8.31 and later versions):
5052
5053 - `unsigned int soap::maxlevel` is the maximum XML nesting depth levels that
5054 the parser permits. Default initialized to `SOAP_MAXLEVEL` (10000), which is
5055 a redefinable macro in stdsoap2.h. Set `soap::maxlevel` to a lower value to
5056 restrict XML parsing nesting depth.
5057
5058 - `long soap::maxlength` is the maximum string content length if not already
5059 constrained by an XML schema validation `maxLength` constraint. Zero means
5060 unlimited string lengths are permitted (unless restricted by XML schema
5061 `maxLength`). Default initialized to `SOAP_MAXLENGTH` (0), which is a
5062 redefinable macro in stdsoap2.h. Set `soap::maxlength` to a positive value
5063 to restrict the number of (wide) characters in strings parsed, restrict
5064 hexBinary byte length, and restrict base64Binary byte length.
5065
5066 - `size_t soap::maxoccurs` is the maximum number of array or container elements
5067 permitted by the parser. Must be greater than zero (0). Default initialized
5068 to `SOAP_MAXOCCURS` (100000), which is a redefinable macro in stdsoap2.h.
5069 Set `soap::maxoccurs` to a positive value to restrict the number of array and
5070 container elements that can be parsed.
5071
5072 - `soap::version` is the SOAP version used, with 0 for non-SOAP, 1 for SOAP1.1,
5073 and 2 for SOAP1.2. This value is normally set by web service operations, and
5074 is otherwise 0 (non-SOAP). Use `soap_set_version(struct soap*, short)` to
5075 set the value. This controls XML namespaces and SOAP id-ref serialization
5076 when applicable with an encodingStyle (see below).
5077
5078 - `const char *soap::encodingStyle` is a string that is used with SOAP
5079 encoding, normally NULL for non-SOAP XML. Set this string to "" (empty
5080 string) to enable SOAP encoding style, which supports id-ref graph
5081 serialization (see also the `SOAP_XML_GRAPH` [context flag](#flags)).
5082
5083 - `int soap::recvfd` is the file descriptor to read and parse source data from.
5084 Default initialized to 0 (stdin). See also [input and output](#io).
5085
5086 - `int soap::sendfd` is the file descriptor to write data to. Default
5087 initialized to 1 (stdout). See also [input and output](#io).
5088
5089 - `const char *is` for C: string to read and parse source data from, overriding
5090 the `recvfd` source. Normally NULL. This value must be reset to NULL or
5091 the parser will continue to read from this string content until the NUL
5092 character. See also [input and output](#io).
5093
5094 - `std::istream *is` for C++: an input stream to read and parse source data
5095 from, overriding the `recvfd` source. Normally NULL. This value must be
5096 reset to NULL or the parser will continue to read from this stream until EOF.
5097 See also [input and output](#io).
5098
5099 - `const char **os` for C: points to a string (a `const char *`) that will be
5100 set to point to the string output. Normally NULL. This value must be reset
5101 to NULL or the next output will result in reassigning the pointer to point to
5102 the next string that is output. The strings are automatically deallocated by
5103 `soap_end(soap)`. See also [input and output](#io).
5104
5105 - `std::ostream *os` for C++: an output stream to write output to. Normally
5106 NULL. This value must be reste to NULL or the next output will be send to
5107 this stream. See also [input and output](#io).
5108
5109 🔝 [Back to table of contents](#)
5110
5111 Error handling and reporting {#errors}
5112 ============================
5113
5114 The gSOAP API functions return `SOAP_OK` (zero) or a non-zero error code. The
5115 error code is stored in `int soap::error` of the current `struct soap` context.
5116 Error messages can be displayed with:
5117
5118 - `void soap_stream_fault(struct soap*, std::ostream &os)` for C++ only, prints
5119 the error message to an output stream.
5120
5121 - `void soap_print_fault(struct soap*, FILE *fd)` prints the error message to a
5122 FILE descriptor.
5123
5124 - `void soap_sprint_fault(struct soap*, char *buf, size_t len)` saves the error
5125 message to a fixed-size buffer allocated with a maximum length.
5126
5127 - `void soap_print_fault_location(struct soap*, FILE *fd)` prints the location
5128 and part of the XML where the parser encountered an error.
5129
5130 C++ exceptions are never raised by gSOAP code, even when data is allocated.
5131 (That is unless the `SOAP_NOTHROW` macro (set to `(std::nothrow)` by default)
5132 is redefined to permit `new` to throw exceptions.)
5133
5134 A `SOAP_EOM` error code is returned when memory was exhausted during
5135 processing of input and/or output of data.
5136
5137 An EOF (`SOAP_EOF` or -1) error code is returned when the parser has hit EOF
5138 but expected more input, or when socket communications timed out. In addition
5139 to the `SOAP_EOF` error, the `int soap::errnum` of the `struct soap` context is
5140 set to the `errno` value of the operation that failed. For timeouts, the
5141 `soap::ernum` value is always 0 instead of an `errno` error code.
5142
5143 Use `soap_xml_error_check(soap->error)` to check for XML errors. This returns
5144 true (non-zero) when a parsing and validation error has occurred.
5145
5146 For example:
5147
5148 ```cpp
5149 #include <sstream>
5150
5151 struct soap *soap = soap_new1(SOAP_XML_INDENT | SOAP_XML_STRICT | SOAP_XML_TREE);
5152 struct ns__record person;
5153 std::stringstream ss;
5154 ss.str("..."); // XML to parse
5155 soap->is = &ss;
5156 if (soap_read__ns__record(soap, &person))
5157 {
5158 if (soap_xml_error_check(soap->error))
5159 std::cerr << "XML parsing error!" << std::endl;
5160 else
5161 soap_stream_fault(soap, std::cerr);
5162 }
5163 else
5164 {
5165 ... // all OK, use person record
5166 }
5167 soap_destroy(soap); // delete objects
5168 soap_end(soap); // delete other data and temp data
5169 soap_free(soap); // free context
5170 ```
5171
5172 When deploying your application on UNIX and Linux systems, UNIX signal handlers
5173 should be added to your code handle signals, in particular `SIGPIPE`:
5174
5175 ```cpp
5176 signal(SIGPIPE, sigpipe_handler);
5177 ```
5178
5179 where the `sigpipe_handler` is a function:
5180
5181 ```cpp
5182 void sigpipe_handler(int x) { }
5183 ```
5184
5185 Other UNIX signals may have to be handled as well.
5186
5187 The gSOAP engine is designed for easy memory cleanup after being interrupted.
5188 Use `soap_destroy(soap)` and `soap_end(soap)`, after which the `soap` context
5189 can be reused.
5190
5191 🔝 [Back to table of contents](#)
5192
5193 Features and limitations {#features}
5194 ========================
5195
5196 In general, to use the generated code:
5197
5198 - Make sure to `#include "soapH.h"` in your code and also define a namespace
5199 table or `#include "ns.nsmap"` with the generated table, where `ns` is the
5200 namespace prefix for services.
5201
5202 - Use soapcpp2 option -j (C++ only) to generate C++ proxy and service objects.
5203 The auto-generated files include documented inferfaces. Compile with
5204 soapC.cpp and link with -lgsoap++, or alternatively compile stdsoap2.cpp.
5205
5206 - Without soapcpp2 option -j: client-side uses the auto-generated
5207 soapClient.cpp and soapC.cpp (or C versions of those). Compile and link with
5208 -lgsoap++ (-lgsoap for C), or alternatively compile stdsoap2.cpp
5209 (stdsoap2.c for C).
5210
5211 - Without soapcpp2 option -j: server-side uses the auto-generated
5212 soapServer.cpp and soapC.cpp (or C versions of those). Compile and link with
5213 -lgsoap++ (-lgsoap for C), or alternatively compile stdsoap2.cpp (stdsoap2.c
5214 for C).
5215
5216 - Use `soap_new()` or `soap_new1(int flags)` to allocate and initialize a
5217 heap-allocated context with or without flags. Delete this context with
5218 `soap_free(struct soap*)`, but only after `soap_destroy(struct soap*)` and
5219 `soap_end(struct soap*)`.
5220
5221 - Use `soap_init(struct *soap)` or `soap_init1(struct soap*, int flags)` to
5222 initialize a stack-allocated context with or without flags. End the use of
5223 this context with `soap_done(struct soap*)`, but only after
5224 `soap_destroy(struct soap*)` and `soap_end(struct soap*)`.
5225
5226 Additional notes with respect to the wsdl2h and soapcpp2 tools:
5227
5228 - Nested classes, structs, and unions in a gSOAP header file are unnested by
5229 soapcpp2.
5230
5231 - Use `#import "file.h"` instead of `#include` to import other header files in
5232 a gSOAP header file for soapcpp2. The `#include`, `#define`, and `#pragma`
5233 are accepted by soapcpp2, but are moved to the very start of the generated
5234 code for the C/C++ compiler to include before all generated definitions.
5235 Often it is useful to add an `#include` with a [volatile type](#toxsd9-2)
5236 that includes the actual type declaration, and to ensure transient types are
5237 declared when these are used in a data binding interface declared in a gSOAP
5238 header file for soapcpp2.
5239
5240 - To remove any SOAP-specific bindings, use soapcpp2 option `-0`.
5241
5242 - A gSOAP header file for soapcpp2 should not include any code statements, only
5243 data type declarations. This includes constructor initialization lists that are
5244 not permitted. Use member initializations instead.
5245
5246 - C++ namespaces are supported. Use wsdl2h option `-qname`. Or add a `namespace
5247 name { ... }` to the header file, but the `{ ... }` MUST cover the entire
5248 header file content from begin to end.
5249
5250 - Optional XML DOM support can be used to store mixed content or literal XML
5251 content. Otherwise, mixed content may be lost. Use wsdl2h option `-d` for
5252 XML DOM support and compile and link with `dom.c` or `dom.cpp`. For details,
5253 see [XML DOM and XPath](http://www.genivia.com/doc/dom/html).
5254
5255 🔝 [Back to table of contents](#)
5256
5257 Removing SOAP namespaces from XML payloads {#nsmap}
5258 ==========================================
5259
5260 The soapcpp2 tool generates a `.nsmap` file that includes two bindings for SOAP
5261 namespaces. We can remove all SOAP namespaces (and SOAP processing logic) with
5262 soapcpp2 option `-0` or by simply setting the two entries to NULL:
5263
5264 ```cpp
5265 struct Namespace namespaces[] =
5266 {
5267 {"SOAP-ENV", NULL, NULL, NULL},
5268 {"SOAP-ENC", NULL, NULL, NULL},
5269 ...
5270 };
5271 ```
5272
5273 Note that once the `.nsmap` is generated, you can copy-paste the content into
5274 your project code. However, if we rerun wsdl2h on updated WSDL/XSD files or
5275 `typemap.dat` declarations then we need to use the updated table.
5276
5277 In cases that no XML namespaces are used at all, for example with
5278 [XML-RPC](http://www.genivia.com/doc/xml-rpc-json/html), you may use an empty
5279 namespace table:
5280
5281 ```cpp
5282 struct Namespace namespaces[] = {{NULL,NULL,NULL,NULL}};
5283 ```
5284
5285 However, beware that any built-in xsi attributes that are rendered will lack
5286 the proper namespace binding. At least we suggest to use `SOAP_XML_NOTYPE` for
5287 this reason.
5288
5289 🔝 [Back to table of contents](#)
5290
5291 Examples {#examples}
5292 ========
5293
5294 Select the project files below to peruse the source code examples.
5295
5296 🔝 [Back to table of contents](#)
5297
5298 Source files
5299 ------------
5300
5301 - `address.xsd` Address book schema
5302 - `address.cpp` Address book app (reads/writes address.xml file)
5303 - `addresstypemap.dat` Schema namespace prefix name preference for wsdl2h
5304 - `graph.h` Graph data binding (tree, digraph, cyclic graph)
5305 - `graph.cpp` Test graph serialization as tree, digraph, and cyclic
5306
5307 🔝 [Back to table of contents](#)
5308
5309 Generated files
5310 ---------------
5311
5312 - `address.h` gSOAP-specific data binding definitions from address.xsd
5313 - `addressStub.h` C++ data binding definitions
5314 - `addressH.h` Serializers
5315 - `addressC.cpp` Serializers
5316 - `address.xml` Address book data generated by address app
5317 - `graphStub.h` C++ data binding definitions
5318 - `graphH.h` Serializers
5319 - `graphC.cpp` Serializers
5320 - `g.xsd` XSD schema with `g:Graph` complexType
5321 - `g.nsmap` xmlns bindings namespace mapping table
5322
5323 🔝 [Back to table of contents](#)
5324
5325 Build steps
5326 -----------
5327
5328 Building the AddressBook example:
5329
5330 wsdl2h -g -t addresstypemap.dat address.xsd
5331 soapcpp2 -0 -CS -I../../import -p address address.h
5332 c++ -I../.. address.cpp addressC.cpp -o address -lgsoap++
5333
5334 Option `-g` produces bindings for global (root) elements in addition to types.
5335 In this case the root element `a:address-book` is bound to `_a__address_book`.
5336 The complexType `a:address` is bound to class `a__address`, which is also the
5337 type of `_a__address_book`. This option is not required, but allows you to use
5338 global element tag names when referring to their serializers, instead of their
5339 type name. Option `-0` removes the SOAP protocol. Options `-C` and `-S`
5340 removes client and server code generation. Option `-p` renames the output
5341 `soap` files to `address` files.
5342
5343 See the `address.cpp` implementation and [related pages](pages.html).
5344
5345 The `addresstypemap.dat` file specifies the XML namespace prefix for the
5346 bindings:
5347
5348 # Bind the address book schema namespace to prefix 'a'
5349
5350 a = "urn:address-book-example"
5351
5352 # By default the xsd:dateTime schema type is translated to time_t
5353 # To map xsd:dateTime to struct tm, enable the following line:
5354
5355 # xsd__dateTime = #import "../../custom/struct_tm.h"
5356
5357 # ... and compile/link with custom/struct_tm.c
5358
5359 The DOB field is a `xsd:dateTime`, which is bound to `time_t` by default. To
5360 change this to `struct tm`, enable the import of the `xsd__dateTime` custom
5361 serializer by uncommenting the definition of `xsd__dateTime` in
5362 `addresstypemap.dat`. Then change `soap_dateTime2s` to `soap_xsd__dateTime2s`
5363 in the code.
5364
5365 Building the graph serialization example:
5366
5367 soapcpp2 -CS -I../../import -p graph graph.h
5368 c++ -I../.. graph.cpp graphC.cpp -o graph -lgsoap++
5369
5370 To compile without using the `libgsoap++` library: simply compile
5371 `stdsoap2.cpp` together with the above.
5372
5373 🔝 [Back to table of contents](#)
5374
5375 Usage
5376 -----
5377
5378 To execute the AddressBook example:
5379
5380 ./address
5381
5382 To execute the Graph serialization example:
5383
5384 ./graph
5385