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4 <html>
5 <head>
6 <!-- Copyright 1999,2000 Clark Cooper <coopercc@netheaven.com>
7 All rights reserved.
8 This is free software. You may distribute or modify according to
9 the terms of the MIT/X License -->
14 </head>
15 <body>
17 <tr>
20 </tr>
21 <tr>
23 <td></td>
24 </tr>
25 </table>
28 <p>Expat is a library, written in C, for parsing XML documents. It's
29 the underlying XML parser for the open source Mozilla project, Perl's
31 other open-source XML parsers.</p>
33 <p>This library is the creation of James Clark, who's also given us
34 groff (an nroff look-alike), Jade (an implemention of ISO's DSSSL
35 stylesheet language for SGML), XP (a Java XML parser package), XT (a
36 Java XSL engine). James was also the technical lead on the XML
37 Working Group at W3C that produced the XML specification.</p>
42 </p>
44 <p>The bulk of this document was originally commissioned as an article
46 Clark Cooper to retain copyright and to distribute it with Expat.
47 This version has been substantially extended to include documentation
48 on features which have been added since the original article was
49 published, and additional information on using the original
50 interface.</p>
52 <hr />
54 <ul>
59 <ul>
61 <ul>
68 </ul>
69 </li>
71 <ul>
78 </ul>
79 </li>
81 <ul>
110 </ul>
111 </li>
113 <ul>
121 </ul>
122 </li>
124 <ul>
144 </ul>
145 </li>
146 </ul>
147 </li>
148 </ul>
150 <hr />
153 <p>Expat is a stream-oriented parser. You register callback (or
154 handler) functions with the parser and then start feeding it the
155 document. As the parser recognizes parts of the document, it will
156 call the appropriate handler for that part (if you've registered one.)
157 The document is fed to the parser in pieces, so you can start parsing
158 before you have all the document. This also allows you to parse really
159 huge documents that won't fit into memory.</p>
161 <p>Expat can be intimidating due to the many kinds of handlers and
162 options you can set. But you only need to learn four functions in
165 <dl>
182 </dl>
186 section also describes in detail the parameters passed to the
187 different types of handlers.</p>
190 above functions (it doesn't need to set a character handler.) The
192 element outline, indenting child elements to distinguish them from the
193 parent element that contains them. The start handler does all the
194 work. It prints two indenting spaces for every level of ancestor
195 elements, then it prints the element and attribute
197 variable.</p>
200 int Depth;
202 void XMLCALL
203 start(void *data, const char *el, const char **attr) {
204 int i;
207 printf(" ");
209 printf("%s", el);
213 }
215 printf("\n");
216 Depth++;
217 } /* End of start handler */
218 </pre>
220 <p>The end tag simply does the bookkeeping work of decrementing
223 void XMLCALL
224 end(void *data, const char *el) {
225 Depth--;
226 } /* End of end handler */
227 </pre>
230 This is used to ensure that the Expat and the callbacks are using the
231 same calling convention in case the compiler options used for Expat
232 itself and the client code are different. Expat tries not to care
233 what the default calling convention is, though it may require that it
234 be compiled with a default convention of "cdecl" on some platforms.
235 For code which uses Expat, however, the calling convention is
237 callbacks should be defined using this annotation.</p>
240 existing working Expat applications don't need to add it (since they
241 are already using the "cdecl" calling convention, or they wouldn't be
242 working). The annotation is only needed if the default calling
243 convention may be something other than "cdecl". To use the annotation
244 safely with older versions of Expat, you can conditionally define it
250 #ifndef XMLCALL
252 #define XMLCALL __cdecl
253 #elif defined(__GNUC__)
254 #define XMLCALL __attribute__((cdecl))
255 #else
256 #define XMLCALL
257 #endif
258 #endif
259 </pre>
261 <p>After creating the parser, the main program just has the job of
262 shoveling the document to the parser so that it can do its work.</p>
264 <hr />
267 <p>The Expat distribution comes as a compressed (with GNU gzip) tar
268 file. You may download the latest version from <a href=
270 unpacking this, cd into the directory. Then follow either the Win32
271 directions or Unix directions below.</p>
275 <p>If you're using the GNU compiler under cygwin, follow the Unix
276 directions in the next section. Otherwise if you have Microsoft's
277 Developer Studio installed, then from Windows Explorer double-click on
278 "expat.dsp" in the lib directory and build and install in the usual
279 manner.</p>
281 <p>Alternatively, you may download the Win32 binary package that
286 <p>First you'll need to run the configure shell script in order to
287 configure the Makefiles and headers for your system.</p>
289 <p>If you're happy with all the defaults that configure picks for you,
290 and you have permission on your system to install into /usr/local, you
291 can install Expat with this sequence of commands:</p>
294 ./configure
295 make
296 make install
297 </pre>
299 <p>There are some options that you can provide to this script, but the
301 can find out all the options available by running configure with just
304 <p>By default, the configure script sets things up so that the library
308 library and header would get installed in
314 <p>Expat's feature set can be configured using a small number of
315 pre-processor definitions. The definition of this symbols does not
316 affect the set of entry points for Expat, only the behavior of the API
317 and the definition of character types in the case of
322 <dd>Include support for using and reporting DTD-based content. If
323 this is defined, default attribute values from an external DTD subset
324 are reported and attribute value normalization occurs based on the
325 type of attributes defined in the external subset. Without
326 this, Expat has a smaller memory footprint and can be faster, but will
327 not load external entities or process conditional sections. This does
328 not affect the set of functions available in the API.</dd>
333 specification is included.</dd>
336 <dd>When defined, character data reported to the application is
337 encoded in UTF-16 using wide characters of the type
344 short</code> is used. Defining this implies
349 integer types to be at least 64 bits in size. This is intended to support
350 processing of very large input streams, where the return values of
354 could overflow. It may not be supported by all compilers, and is turned
355 off by default.</dd>
358 <dd>The number of input bytes of markup context which the parser will
359 ensure are available for reporting via <code><a href=
361 normally set to 1024, and must be set to a positive interger. If this
362 is not defined, the input context will not be available and <code><a
364 always report NULL. Without this, Expat has a smaller memory
365 footprint and can be faster.</dd>
368 <dd>On Windows, this should be set if Expat is going to be linked
369 statically with the code that calls it; this is required to get all
370 the right MSVC magic annotations correct. This is ignored on other
371 platforms.</dd>
372 </dl>
374 <hr />
379 <p>Unless you installed Expat in a location not expected by your
380 compiler and linker, all you have to do to use Expat in your programs
382 in your files that make calls to it and to tell the linker that it
383 needs to link against the Expat library. On Unix systems, this would
385 you'll need to tell the compiler where to look for the Expat header
386 and the linker where to find the Expat library. You may also need to
387 take steps to tell the operating system where to find this library at
388 run time.</p>
390 <p>On a Unix-based system, here's what a Makefile might look like when
391 Expat is installed in a standard location:</p>
394 CC=cc
395 LDFLAGS=
396 LIBS= -lexpat
397 xmlapp: xmlapp.o
398 $(CC) $(LDFLAGS) -o xmlapp xmlapp.o $(LIBS)
399 </pre>
402 the Makefile would look like this:</p>
405 CC=cc
406 CFLAGS= -I/home/me/mystuff/include
407 LDFLAGS=
408 LIBS= -L/home/me/mystuff/lib -lexpat
409 xmlapp: xmlapp.o
410 $(CC) $(LDFLAGS) -o xmlapp xmlapp.o $(LIBS)
411 </pre>
413 <p>You'd also have to set the environment variable
416 LD_LIBRARY_PATH already has some directories in it) in order to run
417 your application.</p>
421 <p>As we saw in the example in the overview, the first step in parsing
422 an XML document with Expat is to create a parser object. There are <a
424 parser object. However, only two of these (<code><a href=
427 constructing a parser for a top-level document. The object returned
428 by these functions is an opaque pointer (i.e. "expat.h" declares it as
429 void *) to data with further internal structure. In order to free the
430 memory associated with this object you must call <code><a href=
433 parser, then your application is responsible for freeing it prior to
436 <p>The objects returned by the parser creation functions are good for
437 parsing only one XML document or external parsed entity. If your
438 application needs to parse many XML documents, then it needs to create
439 a parser object for each one. The best way to deal with this is to
440 create a higher level object that contains all the default
441 initialization you want for your parser objects.</p>
443 <p>Walking through a document hierarchy with a stream oriented parser
444 will require a good stack mechanism in order to keep track of current
445 context. For instance, to answer the simple question, "What element
446 does this text belong to?" requires a stack, since the parser may have
447 descended into other elements that are children of the current one and
448 has encountered this text on the way out.</p>
450 <p>The things you're likely to want to keep on a stack are the
451 currently opened element and it's attributes. You push this
452 information onto the stack in the start handler and you pop it off in
453 the end handler.</p>
455 <p>For some tasks, it is sufficient to just keep information on what
456 the depth of the stack is (or would be if you had one.) The outline
457 program shown above presents one example. Another such task would be
458 skipping over a complete element. When you see the start tag for the
459 element you want to skip, you set a skip flag and record the depth at
460 which the element started. When the end tag handler encounters the
461 same depth, the skipped element has ended and the flag may be
462 cleared. If you follow the convention that the root element starts at
463 1, then you can use the same variable for skip flag and skip
464 depth.</p>
467 void
468 init_info(Parseinfo *info) {
471 /* Other initializations here */
472 } /* End of init_info */
474 void XMLCALL
475 rawstart(void *data, const char *el, const char **attr) {
476 Parseinfo *inf = (Parseinfo *) data;
478 if (! inf->skip) {
479 if (should_skip(inf, el, attr)) {
481 }
482 else
483 start(inf, el, attr); /* This does rest of start handling */
484 }
486 inf->depth++;
487 } /* End of rawstart */
489 void XMLCALL
490 rawend(void *data, const char *el) {
491 Parseinfo *inf = (Parseinfo *) data;
493 inf->depth--;
495 if (! inf->skip)
496 end(inf, el); /* This does rest of end handling */
500 } /* End rawend */
501 </pre>
503 <p>Notice in the above example the difference in how depth is
504 manipulated in the start and end handlers. The end tag handler should
505 be the mirror image of the start tag handler. This is necessary to
506 properly model containment. Since, in the start tag handler, we
509 body. If we'd decided to increment it first thing in the start
510 handler, then we'd have had to decrement it last thing in the end
511 handler.</p>
515 <p>In order to be able to pass information between different handlers
516 without using globals, you'll need to define a data structure to hold
517 the shared variables. You can then tell Expat (with the <code><a href=
519 pointer to this structure to the handlers. This is the first
524 parser itself is passed. When the parser is passed, the user data may
528 <p>One common case where multiple calls to a single handler may need
529 to communicate using an application data structure is the case when
530 content passed to the character data handler (set by <code><a href=
531 "#XML_SetCharacterDataHandler"
533 common first-time mistake with any of the event-oriented interfaces to
534 an XML parser is to expect all the text contained in an element to be
535 reported by a single call to the character data handler. Expat, like
536 many other XML parsers, reports such data as a sequence of calls;
537 there's no way to know when the end of the sequence is reached until a
538 different callback is made. A buffer referenced by the user data
539 structure proves both an effective and convenient place to accumulate
540 character data.</p>
542 <!-- XXX example needed here -->
549 declaration, if present.</p>
551 <p>If an application needs to check the version number (to support
552 alternate processing), it should use the <code><a href=
554 set a handler that uses the information in the XML declaration to
555 determine what to do. This example shows how to check that only a
559 static int wrong_version;
560 static XML_Parser parser;
562 static void XMLCALL
563 xmldecl_handler(void *userData,
564 const XML_Char *version,
565 const XML_Char *encoding,
566 int standalone)
567 {
570 int i;
573 if (version[i] != Version_1_0[i]) {
574 wrong_version = 1;
575 /* also clear all other handlers: */
576 XML_SetCharacterDataHandler(parser, NULL);
577 ...
578 return;
579 }
580 }
581 ...
582 }
583 </pre>
589 performs namespace processing. Under namespace processing, Expat
591 which declare namespaces for the scope of the element in which they
592 occur. This means that your start handler will not see these
593 attributes. Your application can still be informed of these
594 declarations by setting namespace declaration handlers with <a href=
595 "#XML_SetNamespaceDeclHandler"
598 <p>Element type and attribute names that belong to a given namespace
599 are passed to the appropriate handler in expanded form. By default
600 this expanded form is a concatenation of the namespace URI, the
603 name (i.e. the part after the colon). Names with undeclared prefixes
604 are not well-formed when namespace processing is enabled, and will
605 trigger an error. Unprefixed attribute names are never expanded,
606 and unprefixed element names are only expanded when they are in the
607 scope of a default namespace.</p>
612 an explicit prefix is a concatenation of: URI, separator, local name,
613 separator, prefix.</p>
615 <p>You can set handlers for the start of a namespace declaration and
616 for the end of a scope of a declaration with the <code><a href=
618 function. The StartNamespaceDeclHandler is called prior to the start
619 tag handler and the EndNamespaceDeclHandler is called after the
620 corresponding end tag that ends the namespace's scope. The namespace
621 start handler gets passed the prefix and URI for the namespace. For a
622 default namespace declaration (xmlns='...'), the prefix will be null.
623 The URI will be null for the case where the default namespace is being
624 unset. The namespace end handler just gets the prefix for the closing
625 scope.</p>
627 <p>These handlers are called for each declaration. So if, for
628 instance, a start tag had three namespace declarations, then the
629 StartNamespaceDeclHandler would be called three times before the start
630 tag handler is called, once for each declaration.</p>
634 <p>While XML is based on Unicode, and every XML processor is required
636 other encodings may be declared in XML documents or entities. For the
637 main document, an XML declaration may contain an encoding
638 declaration:</p>
639 <pre>
641 </pre>
643 <p>External parsed entities may begin with a text declaration, which
644 looks like an XML declaration with just an encoding declaration:</p>
645 <pre>
647 </pre>
649 <p>With Expat, you may also specify an encoding at the time of
650 creating a parser. This is useful when the encoding information may
651 come from a source outside the document itself (like a higher level
652 protocol.)</p>
655 in Expat:</p>
656 <ul>
661 </ul>
663 <p>Anything else discovered in an encoding declaration or in the
664 protocol encoding specified in the parser constructor, triggers a call
667 structure. Your handler must fill in this structure and return
669 encoding. Otherwise the handler should return
671 to an optional application data structure that you may indicate when
672 you set the handler.</p>
674 <p>Expat places restrictions on character encodings that it can
676 include file:</p>
677 <ol>
678 <li>Every ASCII character that can appear in a well-formed XML document
679 must be represented by a single byte, and that byte must correspond to
680 it's ASCII encoding (except for the characters $@\^'{}~)</li>
682 <li>All characters encoded must have Unicode scalar values less than or
685 <li>No character may be encoded by more that one distinct sequence of
686 bytes</li>
687 </ol>
690 correspond to the 1st byte of an encoding sequence. If the value in
691 the array for a byte is zero or positive, then the byte is a single
692 byte encoding that encodes the Unicode scalar value contained in the
693 array. A -1 in this array indicates a malformed byte. If the value is
695 sequence respectively. Multi-byte sequences are sent to the convert
697 function should return the Unicode scalar value for the sequence or -1
698 if the sequence is malformed.</p>
700 <p>One pitfall that novice Expat users are likely to fall into is that
701 although Expat may accept input in various encodings, the strings that
703 (depending on how Expat was compiled). Your application is responsible
704 for any translation of these strings into other encodings.</p>
708 <p>Expat does not read or parse external entities directly. Note that
709 any external DTD is a special case of an external entity. If you've
711 references are silently ignored. Otherwise, it calls your handler with
712 the information needed to read and parse the external entity.</p>
714 <p>Your handler isn't actually responsible for parsing the entity, but
715 it is responsible for creating a subsidiary parser with <code><a href=
716 "#XML_ExternalEntityParserCreate"
719 other data structures initialized from the parent parser. You may then
722 parser. Since external entities my refer to other external entities,
723 your handler should be prepared to be called recursively.</p>
727 <p>In order to parse parameter entities, before starting the parse,
730 arguments:</p>
731 <dl>
735 <dd>Parse parameter entites and the external subset unless
739 </dl>
741 <p>In order to read an external DTD, you also have to set an external
742 entity reference handler as described above.</p>
747 parsing temporarily from within a handler function, even if more data
748 has already been passed into the parser. Applications for this
749 include</p>
751 <ul>
755 <li>Delaying further processing until additional information is
756 available from some other source.</li>
758 <li>Adjusting processor load as task priorities shift within an
759 application.</li>
761 <li>Stopping parsing completely (simply free or reset the parser
762 instead of resuming in the outer parsing loop). This can be useful
763 if a application-domain error is found in the XML being parsed or if
764 the result of the parse is determined not to be useful after
765 all.</li>
766 </ul>
768 <p>To take advantage of this feature, the main parsing loop of an
769 application needs to support this specifically. It cannot be
770 supported with a parsing loop compatible with Expat 1.95.7 or
771 earlier (though existing loops will continue to work without
772 supporting the stop/resume feature).</p>
774 <p>An application that uses this feature for a single parser will have
775 the rough structure (in pseudo-code):</p>
778 fd = open_input()
779 p = create_parser()
781 if parse_xml(p, fd) {
782 /* suspended */
784 int suspended = 1;
786 while (suspended) {
787 do_something_else()
788 if ready_to_resume() {
789 suspended = continue_parsing(p, fd);
790 }
791 }
792 }
793 </pre>
795 <p>An application that may resume any of several parsers based on
796 input (either from the XML being parsed or some other source) will
797 certainly have more interesting control structures.</p>
800 function mentioned in the pseudo-code above:</p>
803 #define BUFF_SIZE 10240
805 /* Parse a document from the open file descriptor 'fd' until the parse
806 is complete (the document has been completely parsed, or there's
807 been an error), or the parse is stopped. Return non-zero when
808 the parse is merely suspended.
809 */
810 int
811 parse_xml(XML_Parser p, int fd)
812 {
813 for (;;) {
814 int last_chunk;
815 int bytes_read;
816 enum XML_Status status;
818 void *buff = XML_GetBuffer(p, BUFF_SIZE);
819 if (buff == NULL) {
820 /* handle error... */
821 return 0;
822 }
823 bytes_read = read(fd, buff, BUFF_SIZE);
825 /* handle error... */
826 return 0;
827 }
828 status = XML_ParseBuffer(p, bytes_read, bytes_read == 0);
829 switch (status) {
830 case XML_STATUS_ERROR:
831 /* handle error... */
832 return 0;
833 case XML_STATUS_SUSPENDED:
834 return 1;
835 }
836 if (bytes_read == 0)
837 return 0;
838 }
839 }
840 </pre>
843 somewhat simpler, since it only need deal with the return code from
846 function:</p>
849 /* Continue parsing a document which had been suspended. The 'p' and
850 'fd' arguments are the same as passed to parse_xml(). Return
851 non-zero when the parse is suspended.
852 */
853 int
854 continue_parsing(XML_Parser p, int fd)
855 {
856 enum XML_Status status = XML_ResumeParser(p);
857 switch (status) {
858 case XML_STATUS_ERROR:
859 /* handle error... */
860 return 0;
861 case XML_ERROR_NOT_SUSPENDED:
862 /* handle error... */
863 return 0;.
864 case XML_STATUS_SUSPENDED:
865 return 1;
866 }
867 return parse_xml(p, fd);
868 }
869 </pre>
871 <p>Now that we've seen what a mess the top-level parsing loop can
872 become, what have we gained? Very simply, we can now use the <code><a
874 parsing, without having to go to great lengths to avoid additional
875 processing that we're expecting to ignore. As a bonus, we get to stop
877 ready.</p>
881 takes two arguments; the parser being stopped and a flag indicating
882 whether the parse can be resumed in the future.</p>
884 <!-- XXX really need more here -->
887 <hr />
888 <!-- ================================================================ -->
895 XML_Parser XMLCALL
896 XML_ParserCreate(const XML_Char *encoding);
897 </pre>
899 Construct a new parser. If encoding is non-null, it specifies a
900 character encoding to use for the document. This overrides the document
901 encoding declaration. There are four built-in encodings:
902 <ul>
907 </ul>
908 Any other value will invoke a call to the UnknownEncodingHandler.
909 </div>
912 XML_Parser XMLCALL
913 XML_ParserCreateNS(const XML_Char *encoding,
914 XML_Char sep);
915 </pre>
917 Constructs a new parser that has namespace processing in effect. Namespace
918 expanded element names and attribute names are returned as a concatenation
923 concatenated without any separator - this is intended to support RDF processors.
924 It is a programming error to use the null separator with
928 XML_Parser XMLCALL
929 XML_ParserCreate_MM(const XML_Char *encoding,
930 const XML_Memory_Handling_Suite *ms,
931 const XML_Char *sep);
932 </pre>
934 typedef struct {
935 void *(XMLCALL *malloc_fcn)(size_t size);
936 void *(XMLCALL *realloc_fcn)(void *ptr, size_t size);
937 void (XMLCALL *free_fcn)(void *ptr);
938 } XML_Memory_Handling_Suite;
939 </pre>
941 <p>Construct a new parser using the suite of memory handling functions
944 non NULL, then namespace processing is enabled in the created parser
945 and the character pointed at by sep is used as the separator between
946 the namespace URI and the local part of the name.</p>
947 </div>
950 XML_Parser XMLCALL
951 XML_ExternalEntityParserCreate(XML_Parser p,
952 const XML_Char *context,
953 const XML_Char *encoding);
954 </pre>
957 general entity. Context is the context argument passed in a call to a
958 ExternalEntityRefHandler. Other state information such as handlers,
959 user data, namespace processing is inherited from the parser passed as
960 the 1st argument. So you shouldn't need to call any of the behavior
961 changing functions on this parser (unless you want it to act
962 differently than the parent parser).
963 </div>
966 void XMLCALL
967 XML_ParserFree(XML_Parser p);
968 </pre>
970 Free memory used by the parser. Your application is responsible for
972 </div>
975 XML_Bool XMLCALL
976 XML_ParserReset(XML_Parser p,
977 const XML_Char *encoding);
978 </pre>
980 Clean up the memory structures maintained by the parser so that it may
982 ready to start parsing a new document. All handlers are cleared from
983 the parser, except for the unknownEncodingHandler. The parser's external
984 state is re-initialized except for the values of ns and ns_triplets.
985 This function may not be used on a parser created using <code><a href=
990 </div>
997 XML_GetBuffer</a></code> must not be called from within a handler
998 unless they operate on a separate parser instance, that is, one that
999 did not call the handler. For example, it is OK to call the parsing
1001 if they apply to the parser created by
1006 should be considerably less than the maximum value for an integer,
1007 as it could create an integer overflow situation if the added
1008 lengths of a buffer and the unprocessed portion of the previous buffer
1009 exceed the maximum integer value. Input data at the end of a buffer
1010 will remain unprocessed if it is part of an XML token for which the
1011 end is not part of that buffer.</p>
1014 enum XML_Status XMLCALL
1015 XML_Parse(XML_Parser p,
1016 const char *s,
1017 int len,
1018 int isFinal);
1019 </pre>
1021 enum XML_Status {
1022 XML_STATUS_ERROR = 0,
1023 XML_STATUS_OK = 1
1024 };
1025 </pre>
1028 containing part (or perhaps all) of the document. The number of bytes of s
1034 piece of the document. Frequently, the last piece is empty (i.e.
1038 </div>
1041 enum XML_Status XMLCALL
1042 XML_ParseBuffer(XML_Parser p,
1043 int len,
1044 int isFinal);
1045 </pre>
1048 except in this case Expat provides the buffer. By obtaining the
1051 copying of the input.
1052 </div>
1055 void * XMLCALL
1056 XML_GetBuffer(XML_Parser p,
1057 int len);
1058 </pre>
1061 into. A NULL value is returned if Expat can't allocate enough memory for
1062 this buffer. This has to be called prior to every call to
1064 typical use would look like this:
1067 for (;;) {
1068 int bytes_read;
1069 void *buff = XML_GetBuffer(p, BUFF_SIZE);
1070 if (buff == NULL) {
1071 /* handle error */
1072 }
1074 bytes_read = read(docfd, buff, BUFF_SIZE);
1076 /* handle error */
1077 }
1079 if (! XML_ParseBuffer(p, bytes_read, bytes_read == 0)) {
1080 /* handle parse error */
1081 }
1083 if (bytes_read == 0)
1084 break;
1085 }
1086 </pre>
1087 </div>
1090 enum XML_Status XMLCALL
1091 XML_StopParser(XML_Parser p,
1092 XML_Bool resumable);
1093 </pre>
1101 call-backs may still follow because they would otherwise get
1102 lost, including
1103 <ul>
1104 <li> the end element handler for empty elements when stopped in the
1105 start element handler,</li>
1106 <li> the end namespace declaration handler when stopped in the end
1107 element handler,</li>
1108 <li> the character data handler when stopped in the character data handler
1109 while making multiple call-backs on a contiguous chunk of characters,</li>
1110 </ul>
1111 and possibly others.</p>
1113 <p>This can be called from most handlers, including DTD related
1114 call-backs, except when parsing an external parameter entity and
1118 are:</p>
1119 <dl>
1126 </dl>
1128 <p>Since the stop/resume feature requires application support in the
1129 outer parsing loop, it is an error to call this function for a parser
1144 This will be applied to the current parser instance only, that is, if
1145 there is a parent parser then it will continue parsing when the
1146 external entity reference handler returns. It is up to the
1147 implementation of that handler to call <code><a href=
1149 (recursively), if one wants to stop parsing altogether.</p>
1155 </div>
1158 enum XML_Status XMLCALL
1159 XML_ResumeParser(XML_Parser p);
1160 </pre>
1164 within a handler call-back. Returns same status codes as <code><a
1168 parser was not currently suspended.</p>
1171 This must be called on the most deeply nested child parser instance
1172 first, and on its parent parser only after the child parser has
1173 finished, to be applied recursively until the document entity's parser
1174 is restarted. That is, the parent parser will not resume by itself
1175 and it is up to the application to call <code><a href=
1177 appropriate moment.</p>
1180 </div>
1183 void XMLCALL
1184 XML_GetParsingStatus(XML_Parser p,
1185 XML_ParsingStatus *status);
1186 </pre>
1188 enum XML_Parsing {
1189 XML_INITIALIZED,
1190 XML_PARSING,
1191 XML_FINISHED,
1192 XML_SUSPENDED
1193 };
1195 typedef struct {
1196 enum XML_Parsing parsing;
1197 XML_Bool finalBuffer;
1198 } XML_ParsingStatus;
1199 </pre>
1201 <p>Returns status of parser with respect to being initialized,
1202 parsing, finished, or suspended, and whether the final buffer is being
1204 NULL.</p>
1207 </div>
1212 <p>Although handlers are typically set prior to parsing and left alone, an
1213 application may choose to set or change the handler for a parsing event
1214 while the parse is in progress. For instance, your application may choose
1216 way it could do this is to set the character handler when a para start tag
1217 is seen, and unset it for the corresponding end tag.</p>
1220 appropriate handler setter. None of the handler setting functions have
1221 a return value.</p>
1223 <p>Your handlers will be receiving strings in arrays of type
1227 Note that you'll receive them in this form independent of the original
1228 encoding of the document.</p>
1232 void XMLCALL
1233 XML_SetStartElementHandler(XML_Parser p,
1234 XML_StartElementHandler start);
1235 </pre>
1237 typedef void
1238 (XMLCALL *XML_StartElementHandler)(void *userData,
1239 const XML_Char *name,
1240 const XML_Char **atts);
1241 </pre>
1242 <p>Set handler for start (and empty) tags. Attributes are passed to the start
1243 handler as a pointer to a vector of char pointers. Each attribute seen in
1244 a start (or empty) tag occupies 2 consecutive places in this vector: the
1245 attribute name followed by the attribute value. These pairs are terminated
1246 by a null pointer.</p>
1247 <p>Note that an empty tag generates a call to both start and end handlers
1248 (in that order).</p>
1249 </div>
1253 void XMLCALL
1254 XML_SetEndElementHandler(XML_Parser p,
1255 XML_EndElementHandler);
1256 </pre>
1258 typedef void
1259 (XMLCALL *XML_EndElementHandler)(void *userData,
1260 const XML_Char *name);
1261 </pre>
1262 <p>Set handler for end (and empty) tags. As noted above, an empty tag
1263 generates a call to both start and end handlers.</p>
1264 </div>
1268 void XMLCALL
1269 XML_SetElementHandler(XML_Parser p,
1270 XML_StartElementHandler start,
1271 XML_EndElementHandler end);
1272 </pre>
1274 </div>
1278 void XMLCALL
1279 XML_SetCharacterDataHandler(XML_Parser p,
1280 XML_CharacterDataHandler charhndl)
1281 </pre>
1283 typedef void
1284 (XMLCALL *XML_CharacterDataHandler)(void *userData,
1285 const XML_Char *s,
1286 int len);
1287 </pre>
1288 <p>Set a text handler. The string your handler receives
1290 to deal with the end of the string. A single block of contiguous text
1291 free of markup may still result in a sequence of calls to this handler.
1292 In other words, if you're searching for a pattern in the text, it may
1293 be split across calls to this handler. Note: Setting this handler to NULL
1295 processing such a single block of contiguous markup-free text, as the parser
1296 will continue calling back until the end of the block is reached.</p>
1297 </div>
1301 void XMLCALL
1302 XML_SetProcessingInstructionHandler(XML_Parser p,
1303 XML_ProcessingInstructionHandler proc)
1304 </pre>
1306 typedef void
1307 (XMLCALL *XML_ProcessingInstructionHandler)(void *userData,
1308 const XML_Char *target,
1309 const XML_Char *data);
1311 </pre>
1312 <p>Set a handler for processing instructions. The target is the first word
1313 in the processing instruction. The data is the rest of the characters in
1314 it after skipping all whitespace after the initial word.</p>
1315 </div>
1319 void XMLCALL
1320 XML_SetCommentHandler(XML_Parser p,
1321 XML_CommentHandler cmnt)
1322 </pre>
1324 typedef void
1325 (XMLCALL *XML_CommentHandler)(void *userData,
1326 const XML_Char *data);
1327 </pre>
1328 <p>Set a handler for comments. The data is all text inside the comment
1329 delimiters.</p>
1330 </div>
1334 void XMLCALL
1335 XML_SetStartCdataSectionHandler(XML_Parser p,
1336 XML_StartCdataSectionHandler start);
1337 </pre>
1339 typedef void
1340 (XMLCALL *XML_StartCdataSectionHandler)(void *userData);
1341 </pre>
1343 </div>
1347 void XMLCALL
1348 XML_SetEndCdataSectionHandler(XML_Parser p,
1349 XML_EndCdataSectionHandler end);
1350 </pre>
1352 typedef void
1353 (XMLCALL *XML_EndCdataSectionHandler)(void *userData);
1354 </pre>
1356 </div>
1360 void XMLCALL
1361 XML_SetCdataSectionHandler(XML_Parser p,
1362 XML_StartCdataSectionHandler start,
1363 XML_EndCdataSectionHandler end)
1364 </pre>
1366 </div>
1370 void XMLCALL
1371 XML_SetDefaultHandler(XML_Parser p,
1372 XML_DefaultHandler hndl)
1373 </pre>
1375 typedef void
1376 (XMLCALL *XML_DefaultHandler)(void *userData,
1377 const XML_Char *s,
1378 int len);
1379 </pre>
1381 <p>Sets a handler for any characters in the document which wouldn't
1382 otherwise be handled. This includes both data for which no handlers
1383 can be set (like some kinds of DTD declarations) and data which could
1384 be reported but which currently has no handler set. The characters
1385 are passed exactly as they were present in the XML document except
1387 normalized. Note that a byte order mark character is not passed to the
1388 default handler. There are no guarantees about how characters are
1389 divided between calls to the default handler: for example, a comment
1390 might be split between multiple calls. Setting the handler with
1391 this call has the side effect of turning off expansion of references
1392 to internally defined general entities. Instead these references are
1393 passed to the default handler.</p>
1397 </div>
1401 void XMLCALL
1402 XML_SetDefaultHandlerExpand(XML_Parser p,
1403 XML_DefaultHandler hndl)
1404 </pre>
1406 typedef void
1407 (XMLCALL *XML_DefaultHandler)(void *userData,
1408 const XML_Char *s,
1409 int len);
1410 </pre>
1411 <p>This sets a default handler, but doesn't inhibit the expansion of
1412 internal entity references. The entity reference will not be passed
1413 to the default handler.</p>
1417 </div>
1421 void XMLCALL
1422 XML_SetExternalEntityRefHandler(XML_Parser p,
1423 XML_ExternalEntityRefHandler hndl)
1424 </pre>
1426 typedef int
1427 (XMLCALL *XML_ExternalEntityRefHandler)(XML_Parser p,
1428 const XML_Char *context,
1429 const XML_Char *base,
1430 const XML_Char *systemId,
1431 const XML_Char *publicId);
1432 </pre>
1433 <p>Set an external entity reference handler. This handler is also
1434 called for processing an external DTD subset if parameter entity parsing
1442 valid only until the handler returns, so if the referenced entity is
1444 only when the entity is a parameter entity, which is how one can
1445 differentiate between general and parameter entities.</p>
1448 system identifiers. It is set by <code><a
1452 identifier specified in the entity declaration and is never NULL.</p>
1454 <p>There are a couple of ways in which this handler differs from
1455 others. First, this handler returns a status indicator (an
1457 handling of the external entity reference. Returning
1459 calling parser to return an
1462 <p>Second, instead of having the user data as its first argument, it
1463 receives the parser that encountered the entity reference. This, along
1464 with the context parameter, may be used as arguments to a call to
1467 parser, the body of the external entity can be recursively parsed.</p>
1469 <p>Since this handler may be called recursively, it should not be saving
1470 information into global or static variables.</p>
1471 </div>
1474 void XMLCALL
1475 XML_SetExternalEntityRefHandlerArg(XML_Parser p,
1476 void *arg)
1477 </pre>
1479 <p>Set the argument passed to the ExternalEntityRefHandler. If
1483 NULL, the argument passed to the handler function will be the parser
1484 object itself.</p>
1488 ExternalEntityRefHandler do not match. This function takes a
1491 but will not be corrected before Expat 2.0 (at the earliest) to avoid
1492 causing compiler warnings for code that's known to work with this
1493 API. It is the responsibility of the application code to know the
1494 actual type of the argument passed to the handler and to manage it
1495 properly.</p>
1496 </div>
1500 void XMLCALL
1501 XML_SetSkippedEntityHandler(XML_Parser p,
1502 XML_SkippedEntityHandler handler)
1503 </pre>
1505 typedef void
1506 (XMLCALL *XML_SkippedEntityHandler)(void *userData,
1507 const XML_Char *entityName,
1508 int is_parameter_entity);
1509 </pre>
1511 <ol>
1512 <li>An entity reference is encountered for which no declaration
1514 <li>An internal entity reference is read, but not expanded, because
1516 has been called.</li>
1517 </ol>
1519 a parameter entity and zero for a general entity.</p> <p>Note: skipped
1520 parameter entities in declarations and skipped general entities in
1521 attribute values cannot be reported, because the event would be out of
1522 sync with the reporting of the declarations or attribute values</p>
1523 </div>
1527 void XMLCALL
1528 XML_SetUnknownEncodingHandler(XML_Parser p,
1529 XML_UnknownEncodingHandler enchandler,
1530 void *encodingHandlerData)
1531 </pre>
1533 typedef int
1534 (XMLCALL *XML_UnknownEncodingHandler)(void *encodingHandlerData,
1535 const XML_Char *name,
1536 XML_Encoding *info);
1538 typedef struct {
1539 int map[256];
1540 void *data;
1541 int (XMLCALL *convert)(void *data, const char *s);
1542 void (XMLCALL *release)(void *data);
1543 } XML_Encoding;
1544 </pre>
1549 given parser.</p> <p>If the handler knows how to deal with an encoding
1553 at most once per parsed (external) entity. The optional application
1555 the handler.</p>
1557 <p>The map array contains information for every possible possible leading
1559 a single byte sequence and the byte encodes that Unicode value. If the
1560 value is -1, then that byte is invalid as the initial byte in a sequence.
1562 bytes in the sequence and the actual conversion is accomplished by a
1563 call to the function pointed at by convert. This function may return -1
1564 if the sequence itself is invalid. The convert pointer may be null if
1565 there are only single byte codes. The data parameter passed to the convert
1568 bytes to be converted.</p>
1571 parser when it is finished with the encoding. It may be NULL.</p>
1572 </div>
1576 void XMLCALL
1577 XML_SetStartNamespaceDeclHandler(XML_Parser p,
1578 XML_StartNamespaceDeclHandler start);
1579 </pre>
1581 typedef void
1582 (XMLCALL *XML_StartNamespaceDeclHandler)(void *userData,
1583 const XML_Char *prefix,
1584 const XML_Char *uri);
1585 </pre>
1586 <p>Set a handler to be called when a namespace is declared. Namespace
1587 declarations occur inside start tags. But the namespace declaration start
1588 handler is called before the start tag handler for each namespace declared
1589 in that start tag.</p>
1590 </div>
1594 void XMLCALL
1595 XML_SetEndNamespaceDeclHandler(XML_Parser p,
1596 XML_EndNamespaceDeclHandler end);
1597 </pre>
1599 typedef void
1600 (XMLCALL *XML_EndNamespaceDeclHandler)(void *userData,
1601 const XML_Char *prefix);
1602 </pre>
1603 <p>Set a handler to be called when leaving the scope of a namespace
1604 declaration. This will be called, for each namespace declaration,
1605 after the handler for the end tag of the element in which the
1606 namespace was declared.</p>
1607 </div>
1611 void XMLCALL
1612 XML_SetNamespaceDeclHandler(XML_Parser p,
1613 XML_StartNamespaceDeclHandler start,
1614 XML_EndNamespaceDeclHandler end)
1615 </pre>
1617 </div>
1621 void XMLCALL
1622 XML_SetXmlDeclHandler(XML_Parser p,
1623 XML_XmlDeclHandler xmldecl);
1624 </pre>
1626 typedef void
1627 (XMLCALL *XML_XmlDeclHandler)(void *userData,
1628 const XML_Char *version,
1629 const XML_Char *encoding,
1630 int standalone);
1631 </pre>
1632 <p>Sets a handler that is called for XML declarations and also for
1633 text declarations discovered in external entities. The way to
1638 standalone parameter in the declaration, that it was given as no, or
1639 that it was given as yes.</p>
1640 </div>
1644 void XMLCALL
1645 XML_SetStartDoctypeDeclHandler(XML_Parser p,
1646 XML_StartDoctypeDeclHandler start);
1647 </pre>
1649 typedef void
1650 (XMLCALL *XML_StartDoctypeDeclHandler)(void *userData,
1651 const XML_Char *doctypeName,
1652 const XML_Char *sysid,
1653 const XML_Char *pubid,
1654 int has_internal_subset);
1655 </pre>
1656 <p>Set a handler that is called at the start of a DOCTYPE declaration,
1659 will be non-zero if the DOCTYPE declaration has an internal subset.</p>
1660 </div>
1664 void XMLCALL
1665 XML_SetEndDoctypeDeclHandler(XML_Parser p,
1666 XML_EndDoctypeDeclHandler end);
1667 </pre>
1669 typedef void
1670 (XMLCALL *XML_EndDoctypeDeclHandler)(void *userData);
1671 </pre>
1672 <p>Set a handler that is called at the end of a DOCTYPE declaration,
1673 after parsing any external subset.</p>
1674 </div>
1678 void XMLCALL
1679 XML_SetDoctypeDeclHandler(XML_Parser p,
1680 XML_StartDoctypeDeclHandler start,
1681 XML_EndDoctypeDeclHandler end);
1682 </pre>
1684 </div>
1688 void XMLCALL
1689 XML_SetElementDeclHandler(XML_Parser p,
1690 XML_ElementDeclHandler eldecl);
1691 </pre>
1693 typedef void
1694 (XMLCALL *XML_ElementDeclHandler)(void *userData,
1695 const XML_Char *name,
1696 XML_Content *model);
1697 </pre>
1699 enum XML_Content_Type {
1700 XML_CTYPE_EMPTY = 1,
1701 XML_CTYPE_ANY,
1702 XML_CTYPE_MIXED,
1703 XML_CTYPE_NAME,
1704 XML_CTYPE_CHOICE,
1705 XML_CTYPE_SEQ
1706 };
1708 enum XML_Content_Quant {
1709 XML_CQUANT_NONE,
1710 XML_CQUANT_OPT,
1711 XML_CQUANT_REP,
1712 XML_CQUANT_PLUS
1713 };
1715 typedef struct XML_cp XML_Content;
1717 struct XML_cp {
1718 enum XML_Content_Type type;
1719 enum XML_Content_Quant quant;
1720 const XML_Char * name;
1721 unsigned int numchildren;
1722 XML_Content * children;
1723 };
1724 </pre>
1725 <p>Sets a handler for element declarations in a DTD. The handler gets
1726 called with the name of the element in the declaration and a pointer
1727 to a structure that contains the element model. It is the
1728 application's responsibility to free this data structure using
1742 XML_CTYPE_NAME with no quantification. Only the root node can be type
1750 name.</p>
1753 indicate a choice or sequence respectively. The
1756 </div>
1760 void XMLCALL
1761 XML_SetAttlistDeclHandler(XML_Parser p,
1762 XML_AttlistDeclHandler attdecl);
1763 </pre>
1765 typedef void
1766 (XMLCALL *XML_AttlistDeclHandler)(void *userData,
1767 const XML_Char *elname,
1768 const XML_Char *attname,
1769 const XML_Char *att_type,
1770 const XML_Char *dflt,
1771 int isrequired);
1772 </pre>
1773 <p>Set a handler for attlist declarations in the DTD. This handler is
1775 with multiple attributes declared will generate multiple calls to this
1777 element for which the attribute is being declared. The attribute name
1780 type in the declaration with whitespace removed.</p>
1785 parameter, which will be true in the case of "#REQUIRED" attributes.
1786 Attributes which are "#FIXED" will have also have a true
1789 </div>
1793 void XMLCALL
1794 XML_SetEntityDeclHandler(XML_Parser p,
1795 XML_EntityDeclHandler handler);
1796 </pre>
1798 typedef void
1799 (XMLCALL *XML_EntityDeclHandler)(void *userData,
1800 const XML_Char *entityName,
1801 int is_parameter_entity,
1802 const XML_Char *value,
1803 int value_length,
1804 const XML_Char *base,
1805 const XML_Char *systemId,
1806 const XML_Char *publicId,
1807 const XML_Char *notationName);
1808 </pre>
1809 <p>Sets a handler that will be called for all entity declarations.
1811 case of parameter entities and zero otherwise.</p>
1819 legal to have zero-length values. Instead check for whether or not
1821 argument will have a non-NULL value only for unparsed entity
1822 declarations.</p>
1823 </div>
1827 void XMLCALL
1828 XML_SetUnparsedEntityDeclHandler(XML_Parser p,
1829 XML_UnparsedEntityDeclHandler h)
1830 </pre>
1832 typedef void
1833 (XMLCALL *XML_UnparsedEntityDeclHandler)(void *userData,
1834 const XML_Char *entityName,
1835 const XML_Char *base,
1836 const XML_Char *systemId,
1837 const XML_Char *publicId,
1838 const XML_Char *notationName);
1839 </pre>
1840 <p>Set a handler that receives declarations of unparsed entities. These
1841 are entity declarations that have a notation (NDATA) field:</p>
1845 </pre></div>
1846 <p>This handler is obsolete and is provided for backwards
1849 </div>
1853 void XMLCALL
1854 XML_SetNotationDeclHandler(XML_Parser p,
1855 XML_NotationDeclHandler h)
1856 </pre>
1858 typedef void
1859 (XMLCALL *XML_NotationDeclHandler)(void *userData,
1860 const XML_Char *notationName,
1861 const XML_Char *base,
1862 const XML_Char *systemId,
1863 const XML_Char *publicId);
1864 </pre>
1866 </div>
1870 void XMLCALL
1871 XML_SetNotStandaloneHandler(XML_Parser p,
1872 XML_NotStandaloneHandler h)
1873 </pre>
1875 typedef int
1876 (XMLCALL *XML_NotStandaloneHandler)(void *userData);
1877 </pre>
1879 This happens when there is an external subset or a reference to a
1880 parameter entity, but does not have standalone set to "yes" in an XML
1883 error.</p>
1884 </div>
1888 <p>These are the functions you'll want to call when the parse
1890 occurred), although the position reporting functions are useful outside
1891 of errors. The position reported is the byte position (in the original
1892 document or entity encoding) of the first of the sequence of
1893 characters that generated the current event (or the error that caused
1895 exceptions are callbacks trigged by declarations in the document
1896 prologue, in which case they exact position reported is somewhere in the
1897 relevant markup, but not necessarily as meaningful as for other
1898 events.</p>
1900 <p>The position reporting functions are accurate only outside of the
1901 DTD. In other words, they usually return bogus information when
1902 called from within a DTD declaration handler.</p>
1905 enum XML_Error XMLCALL
1906 XML_GetErrorCode(XML_Parser p);
1907 </pre>
1909 Return what type of error has occurred.
1910 </div>
1913 const XML_LChar * XMLCALL
1914 XML_ErrorString(enum XML_Error code);
1915 </pre>
1917 Return a string describing the error corresponding to code.
1918 The code should be one of the enums that can be returned from
1920 </div>
1923 XML_Index XMLCALL
1924 XML_GetCurrentByteIndex(XML_Parser p);
1925 </pre>
1927 Return the byte offset of the position. This always corresponds to
1931 </div>
1934 XML_Size XMLCALL
1935 XML_GetCurrentLineNumber(XML_Parser p);
1936 </pre>
1938 Return the line number of the position. The first line is reported as
1940 </div>
1943 XML_Size XMLCALL
1944 XML_GetCurrentColumnNumber(XML_Parser p);
1945 </pre>
1947 Return the offset, from the beginning of the current line, of
1948 the position.
1949 </div>
1952 int XMLCALL
1953 XML_GetCurrentByteCount(XML_Parser p);
1954 </pre>
1956 Return the number of bytes in the current event. Returns
1958 entity and for the end-tag event for empty element tags (the later can
1959 be used to distinguish empty-element tags from empty elements using
1960 separate start and end tags).
1961 </div>
1964 const char * XMLCALL
1965 XML_GetInputContext(XML_Parser p,
1966 int *offset,
1967 int *size);
1968 </pre>
1971 <p>Returns the parser's input buffer, sets the integer pointed at by
1974 the size of the returned buffer.</p>
1976 <p>This should only be called from within a handler during an active
1977 parse and the returned buffer should only be referred to from within
1978 the handler that made the call. This input buffer contains the
1979 untranslated bytes of the input.</p>
1981 <p>Only a limited amount of context is kept, so if the event
1982 triggering a call spans over a very large amount of input, the actual
1983 parse position may be before the beginning of the buffer.</p>
1986 return NULL.</p>
1987 </div>
1991 <p>The functions in this section either obtain state information from
1992 the parser or can be used to dynamicly set parser options.</p>
1995 void XMLCALL
1996 XML_SetUserData(XML_Parser p,
1997 void *userData);
1998 </pre>
2000 This sets the user data pointer that gets passed to handlers. It
2001 overwrites any previous value for this pointer. Note that the
2002 application is responsible for freeing the memory associated with
2004 call this when there's already a pointer there, and you haven't freed
2005 the memory associated with it, then you've probably just leaked
2006 memory.
2007 </div>
2010 void * XMLCALL
2011 XML_GetUserData(XML_Parser p);
2012 </pre>
2014 This returns the user data pointer that gets passed to handlers.
2015 It is actually implemented as a macro.
2016 </div>
2019 void XMLCALL
2020 XML_UseParserAsHandlerArg(XML_Parser p);
2021 </pre>
2023 After this is called, handlers receive the parser in their
2027 </div>
2030 enum XML_Status XMLCALL
2031 XML_SetBase(XML_Parser p,
2032 const XML_Char *base);
2033 </pre>
2035 Set the base to be used for resolving relative URIs in system
2037 there's no memory to store base, otherwise it's
2039 </div>
2042 const XML_Char * XMLCALL
2043 XML_GetBase(XML_Parser p);
2044 </pre>
2046 Return the base for resolving relative URIs.
2047 </div>
2050 int XMLCALL
2051 XML_GetSpecifiedAttributeCount(XML_Parser p);
2052 </pre>
2054 When attributes are reported to the start handler in the atts vector,
2055 attributes that were explicitly set in the element occur before any
2056 attributes that receive their value from default information in an
2057 ATTLIST declaration. This function returns the number of attributes
2058 that were explicitly set times two, thus giving the offset in the
2060 attribute set due to defaults. It supplies information for the last
2061 call to a start handler. If called inside a start handler, then that
2062 means the current call.
2063 </div>
2066 int XMLCALL
2067 XML_GetIdAttributeIndex(XML_Parser p);
2068 </pre>
2070 Returns the index of the ID attribute passed in the atts array in the
2073 attribute. If called inside a start handler, then that means the
2074 current call.
2075 </div>
2078 enum XML_Status XMLCALL
2079 XML_SetEncoding(XML_Parser p,
2080 const XML_Char *encoding);
2081 </pre>
2083 Set the encoding to be used by the parser. It is equivalent to
2084 passing a non-null encoding argument to the parser creation functions.
2090 </div>
2093 int XMLCALL
2094 XML_SetParamEntityParsing(XML_Parser p,
2095 enum XML_ParamEntityParsing code);
2096 </pre>
2098 This enables parsing of parameter entities, including the external
2099 parameter entity that is the external DTD subset, according to
2102 <ul>
2106 </ul>
2107 </div>
2110 enum XML_Error XMLCALL
2111 XML_UseForeignDTD(XML_Parser parser, XML_Bool useDTD);
2112 </pre>
2114 <p>This function allows an application to provide an external subset
2115 for the document type declaration for documents which do not specify
2116 an external subset of their own. For documents which specify an
2117 external subset in their DOCTYPE declaration, the application-provided
2118 subset will be ignored. If the document does not contain a DOCTYPE
2120 application-provided subset will be parsed, but the
2123 called. The setting of parameter entity parsing, controlled using
2127 <p>The application-provided external subset is read by calling the
2128 external entity reference handler set via <code><a href=
2129 "#XML_SetExternalEntityRefHandler"
2133 <p>If this function is called after parsing has begun, it returns
2136 DTD support, it returns
2142 the document had a DTD with an external subset. This holds true even if
2143 the external entity reference handler returns without action.</p>
2144 </div>
2147 void XMLCALL
2148 XML_SetReturnNSTriplet(XML_Parser parser,
2149 int do_nst);
2150 </pre>
2152 <p>
2153 This function only has an effect when using a parser created with
2156 sets whether or not prefixes are returned with names qualified with a
2158 non-zero, then afterwards namespace qualified names (that is qualified
2159 with a prefix as opposed to belonging to a default namespace) are
2160 returned as a triplet with the three parts separated by the namespace
2161 separator specified when the parser was created. The order of
2162 returned parts is URI, local name, and prefix.</p> <p>If
2164 default manner, URI then local_name separated by the namespace
2165 separator.</p>
2166 </div>
2169 void XMLCALL
2170 XML_DefaultCurrent(XML_Parser parser);
2171 </pre>
2173 This can be called within a handler for a start element, end element,
2174 processing instruction or character data. It causes the corresponding
2175 markup to be passed to the default handler set by <code><a
2179 not a default handler.
2180 </div>
2183 XML_LChar * XMLCALL
2184 XML_ExpatVersion();
2185 </pre>
2188 </div>
2191 struct XML_Expat_Version XMLCALL
2192 XML_ExpatVersionInfo();
2193 </pre>
2195 typedef struct {
2196 int major;
2197 int minor;
2198 int micro;
2199 } XML_Expat_Version;
2200 </pre>
2202 Return the library version information as a structure.
2203 Some macros are also defined that support compile-time tests of the
2204 library version:
2205 <ul>
2209 </ul>
2210 Testing these constants is currently the best way to determine if
2211 particular parts of the Expat API are available.
2212 </div>
2215 const XML_Feature * XMLCALL
2216 XML_GetFeatureList();
2217 </pre>
2219 enum XML_FeatureEnum {
2220 XML_FEATURE_END = 0,
2221 XML_FEATURE_UNICODE,
2222 XML_FEATURE_UNICODE_WCHAR_T,
2223 XML_FEATURE_DTD,
2224 XML_FEATURE_CONTEXT_BYTES,
2225 XML_FEATURE_MIN_SIZE,
2226 XML_FEATURE_SIZEOF_XML_CHAR,
2227 XML_FEATURE_SIZEOF_XML_LCHAR,
2228 XML_FEATURE_NS,
2229 XML_FEATURE_LARGE_SIZE
2230 };
2232 typedef struct {
2233 enum XML_FeatureEnum feature;
2234 XML_LChar *name;
2235 long int value;
2236 } XML_Feature;
2237 </pre>
2240 Expat was configured at compile time. Most applications should not
2241 need to worry about this, but this information is otherwise not
2242 available from Expat. This function allows code that does need to
2243 check these features to do so at runtime.</p>
2248 identifying the feature-test macros Expat was compiled with. Since an
2249 application that requires this kind of information needs to determine
2255 all.</p>
2257 <p>Some features have an associated value. If there isn't an
2259 time, the following features have been defined to have values:</p>
2261 <dl>
2264 character.</dd>
2267 character.</dd>
2269 <dd>The maximum number of characters of context which can be
2272 </dl>
2273 </div>
2276 void XMLCALL
2277 XML_FreeContentModel(XML_Parser parser, XML_Content *model);
2278 </pre>
2283 This function should not be used for any other purpose.
2284 </div>
2286 <p>The following functions allow external code to share the memory
2288 is especially useful for third-party libraries that interact with a
2289 parser object created by application code, or heavily layered
2290 applications. This can be essential when using dynamically loaded
2291 libraries which use different C standard libraries (this can happen on
2292 Windows, at least).</p>
2295 void * XMLCALL
2296 XML_MemMalloc(XML_Parser parser, size_t size);
2297 </pre>
2301 pointer to the memory or NULL on failure. Memory allocated in this
2304 </div>
2307 void * XMLCALL
2308 XML_MemRealloc(XML_Parser parser, void *ptr, size_t size);
2309 </pre>
2317 a pointer to the memory or NULL on failure. On success, the original
2318 block has either been expanded or freed. On failure, the original
2319 block has not been freed; the caller is responsible for freeing the
2320 original block. Memory allocated in this way must be freed using
2323 </div>
2326 void XMLCALL
2327 XML_MemFree(XML_Parser parser, void *ptr);
2328 </pre>
2333 </div>
2335 <hr />
2339 </div>
2340 </body>
2341 </html>