3 .\" (C) 1999 George Lebl <jirka@5z.com>
5 .\" This manual page is covered by the terms of the GNU General
8 .TH GOB 1 "GOB @VERSION@"
10 GOB \- The GTK+ Object Builder
18 GTK+ Object Builder is a simple preprocessor for easily creating
19 GTK+ objects. It does not parse any C code and ignores any C errors. It
20 is in spirit similar to things like lex or yacc.
26 Display a simple help screen.
29 Display version information (note, --version was not added until 0.92.0)
32 Exit with an error code even when you encounter a warning.
35 Exit with an error only on errors, not on warnings, this is the default.
41 Never add the extern "C" to the header.
44 Never generate any code with GNU C extensions. However all the GNU C
45 extensions are always wrapped in #ifdef __GNUC__, so code using them compiles
46 correctly even on non-GNU compilers. This option is for purists only.
47 (using GNU extensions some warnings are eliminated, some ugly hacks and there
48 is better argument type safety, so it's good to use them)
51 Don't touch the generated header file unless it really changed, this avoids
52 spurious rebuilds, but can confuse some make systems (automake in particular),
53 so it is not enabled by default. Private header is still touched even if
56 .B --always-private-header
57 Always create a \fB<basename>-private.h\fR file, even if it would be empty.
58 Otherwise, it is only created when there are private data members in the class.
59 This option implicitly negates --no-private-header
61 .B --no-private-header
62 Never create a private header file. If we use any private data members,
63 define the private data structure at the point in the .c source where
64 the class definition begins. This option implicitly negates
65 --always-private-header
68 Do not write any output files, just check syntax of the input file.
71 Do not print out the '#line' statements into the output. Useful for debugging
72 the auto-generated generated code.
75 Do not create the Self and SelfClass type aliases and the SELF, IS_SELF
76 and SELF_CLASS macros.
78 .B --no-kill-underscores
79 Do not remove the initial underscore from method names.
83 Because we need to parse out different parts of the typename, sometimes you
84 need to specify the typename with some special syntax. Types are specified in
85 capitalized form and words are separated by ':'. The first word of the type
86 (which can be empty) is the "namespace". This fact is for example used for the
87 type checking macro and the type macro. For "Gtk:New:Button", the macros will
88 be GTK_IS_NEW_BUTTON and GTK_TYPE_NEW_BUTTON. This colon separated format of
89 typenames is used in the class declaration header and for method argument
94 The filenames are created from the typename. The words are
95 separated by '-' and all in lower case. For example for an object named
96 "Gtk:New:Button", the files are \fBgtk-new-button.c\fR and
97 \fBgtk-new-button.h\fR.
98 If you are using C++ mode, the output .c file will in fact be a .cc file.
99 If you have any private data members, a private header file will also
100 be created, called \fB<basename>-private.h\fR (for the example above it
101 would be gtk-new-button-private.h).
102 The public header file is created to be human readable and to be used as a
103 reference to the object. The .c source file is not created as a human
104 readable source and is littered with #line statements, which make the
105 compiler attempt to point you to the right line in your .gob file in
106 case of parsing errors. The output should not be edited by hand, and
107 you should only edit the .gob file.
109 .SH INCLUDING NORMAL C CODE IN THE OUTPUT FILES
111 To include some code directly in the output C file begin with '%{'
112 on an empty line and end the code with a '%}' on an empty line. These
113 sections will appear in the output files in the order they are given.
114 There are several other \fIsections\fR to which you can put code. You can
115 put it in the 'header' section (which can be abbreviated 'h') and it will
116 go into the public header file. You can also put it in the 'privateheader'
117 section (abbreviated 'ph') which will make the code go into the private
118 header file. Sometimes you want some code (other includes) to appear before
119 the extern "C" and the protecting define. To do this you can put them
120 into the 'headertop' (or 'ht') section. You may wish to include code or
121 comments in all the files, which you can do by putting them into the 'all'
122 (or 'a') section. Similarly, code you wish to appear at the top of all
123 files go in the 'alltop' (or 'at') section. For example:
127 /* this will be on top of all output files */
131 /* this will be on top of the public header */
135 /* this will go into the private header file */
139 /* will be included in the header */
140 void somefunc(int i);
144 /* will be included in all files */
148 /* will be included in the C file */
159 Gob will automatically include the class header file at the top of the .c
160 source file. If you wish to include it somewhere else, put the include
161 into some %{ %} section above the class definition, and gob will not include
162 it automatically. This way you can avoid circular includes and control
163 where in the file do you want to include the header.
165 If you made any data members private, gob will also create a source file
166 that will be called \fB<basename>-private.h\fR. Same rule as above applies
167 for this just as it does for the regular header file. If you do explicitly
168 include the regular header file, you should always include this private
169 header file below it. That is, if you use any private data members. If you
170 don't, the private header file automatically includes the public header file,
171 and thus the public header file will be indirectly included at the very top
174 .SH MAKING A NEW CLASS
178 There can be only one class per input file. Defining a class
179 is sort of like in Java, you define the class and write inline code
180 directly into the class definition. To define a class you need to specify
181 the new object name and the name of the object from which it is derived
182 from, such as this "class <new type> from <parent type> { <class code> }".
186 class Gtk:New:Button from Gtk:Button {
194 There are five types of data members. Three of them are normal data numbers,
195 one is class wide (global) in scope and one is a virtual one, usually linked to
196 a normal data member or a class wide data member. The three normal data
197 members are public, protected and private. Public and protected are basically
198 just entries in the object structure, while private has it's own dynamically
199 allocated private structure. Protected members are always put after the public
200 one in the structure and are marked protected in the header file. There is
201 only one identifier allowed per typename unlike in normal C. Example:
205 private GtkWidget *h;
210 Public and protected data members are accessed normally as members of
211 the object struct. Example where 'i' is as above a public data member:
218 The private data members are defined in a structure which is only available
219 inside the .c file, or by including a private header file. You must access
220 them using the structure _priv. Example
221 where 'h' is the private data member (as in the above example):
224 object->_priv->h = NULL;
227 The _priv structure is defined in the \fB<basename>-private.h\fR.
228 This file is automatically included if you don't include it yourself. You
229 should always explicitly include it in your .gob file if you explicitly also
230 include the main header file. The reason it is a separate header file is
231 that you can also include it in other places that need to access this objects
232 private data, such as if you have the majority of functionality of an object
233 in a separate .c file. Or if a derived object needs to access the protected
236 In case you use the \fB--no-private-header\fR option, no
237 private header file is created and you can only access the _priv pointer
238 below the class definition in the .gob file.
240 Also note that this structure is dynamically allocated, and is freed in the
241 finalize handler. If you override the finalized handler, your code will be
242 run first and only then will the _priv structure be freed.
244 Classwide data members:
246 Sometimes you want a datamember to be shared by all objects. You then need
247 the "classwide" scope keyword. So for example the following adds a global
254 To access the member you do the standard voodoo of getting the class from the
255 object and casting it to your class pointer. Thus the following would work:
258 SELF_CLASS(GTK_OBJECT(object)->klass)->foo = 20;
262 Automatic Initialization (0.93.0 and higher only):
264 You can automatically initialize the public private and protected data members
265 without having to add an init method. The advantage here is that
266 initialization is kept close to the definition of the data member and thus
267 it's easier to check. To do this, just add a '=' followed by a number or
268 a token. It is also possible to include arbitrary C code for more elaborate
269 initializations by putting it all in curly braces. Note that the curly braces
270 will not be printed into the output, but since gob does not C parsing it needs
271 them to figure out where the C code ends. The code will be inserted into the
272 init method, above the user defined body. So for example the following
273 will initialize an integer to -1 and a string with a newly allocated string
278 private char *bar = {g_strdup("hello")};
282 Automatic Destruction (0.93.0 and higher only):
284 Most data stored as pointers needs to have a function called when the object
285 is destroyed, to either free it or give up a reference. Gob will let you
286 define a function to be called on the data the object is destroyed. This is
287 achieved by putting 'destroywith' followed by a function name after the
288 variable definition. It is only called if the data you defined this on
289 is not NULL, so you cans specify functions which do not handle NULL. It
290 is very much like the GDestroyNotify function used in GTK+ and glib in many
291 places. Unlike many other places, gob will not enforce any kind of type
292 safety here so be a little bit more careful. Any function you give it will
293 be called as a "void function(void *)". It will in fact be cast into such
294 a form before called. This is to avoid spurious warnings for gtk calls to
295 subclass methods. The function needs not be of that form exactly, it just has
296 to take one argument which is the pointer to the data. You should also not
297 define this on any non-pointer data as the results may be undefined.
301 public Gtk:Widget *window = NULL
302 destroywith gtk_widget_destroy;
303 public char *foo = {g_strdup("bar")}
307 Note that the function name you give must be a real function and not macro.
308 Also note that this is always called in the "destroy" method of GtkObject.
309 It is always called after any user defined body of the destroy handler.
311 Sometimes you may want to run arbitrary code on destruction. While this can
312 be perfectly well done in the destroy handler. Depending on the style you
313 may want to include all destruction/initialization code together with the
314 definition of the data member. Thus you may want to put arbitrary code which
315 will then be inserted into the "destroy" method of GtkObject. This can be
316 done with the "destroy" keyword followed by arbitrary code in curly braces.
317 Inside this code a macro called VAR will be define which refers to your
318 variable. So for example destroying a GString can be either done with
319 a helper routine or the following code:
322 public GString *string = {g_string_new(NULL)}
324 if(VAR) g_string_free(VAR, TRUE);
328 The thing to remember with these is that there are many ways to do this
329 and you'd better be consistent in your code in how you use the above things.
330 Also defining a helper routine that will do the destruction will be a nicer
331 thing to do if that's a possibility. The "destroy" keyword with code does
332 take up more space in the file and it may become more cluttered.
334 The data is zeroed out after being destroyed. This is to make debugging easier
335 in case your code might try to access an already destroyed object. In case
336 you have overridden the destroy method, your code will be run first and
337 only then will the destructors be called. You should not however make any
338 assumptions about the order at which the destructors are called. If you have
339 interdependencies between destructors for different data members, you will
340 have to do this in your own destroy override function.
344 The fourth type of a data member an argument type. It is a named data member
345 which is one of the features of the GTK+ object system. You need to define a
346 get and a set handler. They are fragments of C code that will be used to get
347 the value or set the value of the argument. Inside them you can use the define
348 ARG to which you assign the data or get the data. You can also use the
349 identifier "self" as pointer to the object instance. The type is defined as
350 one of the gtk type enums, but without the GTK_TYPE_ prefix. For example:
354 argument INT height set { self->height = ARG; } get { ARG = self->height; };
358 If you don't define a set or a get handler it will be a read-only
359 or a write-only argument. If you want to add extra argument flags, add
360 them into parenthesis after the argument keyword, separated by '|' and
361 without the GTK_ARG_ prefix. For example:
365 argument (CONSTRUCT) INT height get { ARG = self->height; };
368 This makes the argument settable even before the object is constructed, so
369 that people can pass it to gtk_object_new function. Useful is also
370 CONSTRUCT_ONLY flag which makes the argument only available during
371 construction of the object.
373 Since 0.92.1, gob creates macros which can be used for type safe access to
374 gtk arguments. The macros are called <type>_ARG_<argument name>(x) and
375 <type>_GET_ARG_<argument name>(x). They define both the string and the
376 value part of the argument. So for setting an argument of height, one would
377 use (for object type My:Object):
380 gtk_object_set(GTK_OBJECT(object),
381 MY_OBJECT_ARG_HEIGHT(7),
385 And for getting, you would use:
389 gtk_object_set(GTK_OBJECT(object),
390 MY_OBJECT_GET_ARG_HEIGHT(&height),
394 Note however that the type safety only works completely on GNU C compilers.
395 The code will compile on other compilers but with minimal type safety.
397 To get good type safety on POINTER types however, you should specify
398 an optional C type that gob should use. For other then POINTER types
399 this is redundant but possible. To do this, place '(type <c type>)'
400 right after the GTK+ type. Example:
403 argument POINTER (type char *) foo set { /* foo */ } get { /* bar */ };
407 Sometimes it can become tiresome to type in the set and get handlers if
408 they are trivial. So gob since version 0.93.0 provides automatic argument
409 linking to data members. There are three different cases it handles, direct
410 link (keyword 'link'), string linking (keyword 'stringlink') and object
411 linking (keyword 'objectlink'). You just place the keyword after the argument
412 name instead of the get/set handlers. It will link to a data member of the
413 same name that was defined earlier in the input file. Best is to see examples:
417 argument INT foo link;
424 argument INT (type int) foo
425 get { ARG = self->foo; }
426 set { self->foo = ARG; };
433 argument POINTER foo stringlink;
440 argument POINTER (type char *) foo
442 ARG = self->_priv->foo;
444 g_free(self->_priv->foo);
445 self->_priv->foo = g_strdup(ARG);
449 And for the objectlink we would have:
452 public Gtk:Object * foo;
453 argument POINTER foo objectlink;
459 protected Gtk:Object * foo;
460 argument POINTER (type Gtk:Object *) foo
465 gtk_object_unref(self->foo);
468 gtk_object_ref(self->foo);
473 As you see it will handle NULLs correctly (for the string, g_free and g_strdup
474 handle NULLs). And it will also handle private, protected and public members.
475 Also you should notice that when the get is used, only a pointer is always
476 returned for both objectlink and strinklink. So you should treat the returned
477 value with care and never free it (and notice that it will only be around
478 until you set the argument to something else or destroy the object).
482 There is a whole array of possible methods. The three normal,
483 "familiar" method types are private, protected and public. Public are
484 defined as normal functions with a prototype in the header file.
485 Protected methods are defined as normal methods (which you can call from other
486 files), but their prototype is placed in the private header file. Private
488 are defined as static functions with prototypes at the top of the .c
489 file. Then there are signal, virtual and override methods. More on those
491 define init and class_init methods with a special definition if you want
492 to add code to the constructors or you can just leave them out.
493 You can also not define a body for a method, by just using ';' instead of a
494 body. This will define an empty function. You can't do this for non-void
495 regular public, private or protected methods, however it is acceptable for
496 non-void virtual, signal and override methods.
498 Function argument lists:
500 For all but the init and class_init methods, you use the
501 following syntax for arguments. The first argument can be just "self",
502 which gob will translate into a pointer to the object instance. The rest
503 of the arguments are very similar to normal C arguments. If the
504 typename is an object pointer you should use the syntax defined above
505 with the words separated by ':'
509 <type> <argument id> (check <list of checks>)
512 The checks are glib type preconditions, and can be the following:
513 "null", which tests pointers for being NULL, "type" which checks GTK+
514 object pointers for being the right type, "<test> <number>" which tests
515 numeric arguments for being a certain value. The test can be a <,>,<=,>=
519 public int foo(self, int h (check > 0 < 11), Gtk:Widget *w (check null type))
523 This will be the prototype of a function which has a self pointer
524 as the first argument, an integer argument which will be checked and has
525 to be more then 0 and less then 11, and a pointer to a GtkWidget object
526 instance and it is checked for being null and the type will also be
531 Methods which have a return value, there also has to be something
532 returned if there is an error, such as if a precondition is not met. The
533 default is 0, casted to the type of the method. If you need to return
534 something else then you can specify an "onerror" keyword after the
535 prototype and after that a number, a token (an identifier) or a bit of C
536 code enclosed in braces {}. The braces will not be printed into the
537 output, they just delimit the string. For example:
540 public void * get_something(self, int i (check >= 0)) onerror NULL {
545 The onerror value is also used in overrides that have a return value, in
546 case there isn't a parent method, PARENT_HANDLER will return it. More about
551 Some signal and virtual methods have a return type. But what happens if
552 there is no default handler and no one connects to a signal. GOB will
553 normally have the wrappers return whatever you specify with onerror or '0'
554 if you haven't specified anything. But since 0.93.2 you can specify a default
555 return value with the keyword 'defreturn'. It's use is identical to the
556 use of onerror, and you can in fact use both at the same time. Example
559 virtual int get_some_int(self) onerror -1 defreturn 10 ;
562 That is an empty virtual method (in C++ terms a pure virtual). If you never
563 specify any handler for it in the derived children it will just return 10.
567 There are two methods that handle the construction of an object, init and
568 class_init. You define them by just using the init or class_init keyword
569 with an untyped argument in the argument list. The argument will be
570 usable in your function as a pointer to your object or class depending if
571 it's init or class_init.
576 /* initialize the object here */
582 /* initialize the class, this is rarely needed */
587 The class_init function is very rarely needed as all standard class
588 initialization is taken care of for you by gob itself. The init function
589 should on the other hand be used whenever you need to construct or initialize
590 anything in the object to put it into a sane state. Sometimes you need
591 some arguments, for this you should either use a construct method and a
592 new function like many GTK+ widgets, and/or a CONSTRUCT or CONSTRUCT_ONLY
597 Virtual methods are basically pointers in the class structure,
598 so that one can override the method in derived methods. They can be empty
599 (if you put ';' instead of the C code). A wrapper will also be defined
600 which makes calling the methods he same as public methods. This type of
601 method is just a little bit "slower" then normal functions, but not as
602 slow as signals. You define them by using "virtual" keyword before the
603 prototype. If you put the keyword "private" right after the "virtual"
604 keyword, the wrapper will not be a public method, but a private one.
605 You can do the same with "protected" to make a protected wrapper.
609 Signals are methods to which the user can bind other handlers
610 and override the default handler. The default handler is basically the
611 method body. This is the most versatile and flexible type of a method
612 and also the slowest. You need to specify a whole bunch of things when
613 you define a signal. One thing is when the default handler will be run,
614 first or last. You specify that by "first" or "last" right after the
615 "signal" keyword. Then you need to define the gtk enum types (again
616 without the GTK_TYPE_ prefix). For that you define the return types
617 and the types of arguments after the "self" pointer (not including the
618 "self" pointer). You put it in the following syntax "<return type> (<list
619 of arguments>)". If the return type is void, the type should be "NONE",
620 the same should be for the argument list. The rest of the prototype is
621 the same as for other method types. The body can also be empty, and
622 also there is a public method wrapper which you can use for calling the
623 signal just like a public method. Example:
626 signal first INT(POINTER,INT)
627 int do_something(self, Gtk:Widget *w (check null type), int length)
636 signal last NONE(NONE) void foo(self);
640 If you don't want the wrapper that emits the signal to be public, you can
641 include the keyword "private" after the "signal" keyword. This will make
642 the wrapper a normal private method. You can also make a protected wrapper
643 by using "protected" instead of "private".
645 If you don't define a "first" or a "last", the default will be taken as
648 You can also add additional flags. You do this just like with the argument
649 flags, although this is probably very rare. These are the GTK_RUN_* flags,
650 and you can add them without the GTK_RUN_ prefix into a parenthesis, just
651 after the "signal" keyword. By default all public signals are GTK_RUN_ACTION.
655 If you need to override some method (a signal or a virtual method
656 of some class in the parent tree of the new object), you can define and
657 override method. After the "override" keyword, you should put the
658 typename of the class you are overriding a method from. Other then that
659 it is the same as for other methods. The "self" pointer in this case
660 should be the type of the method you are overriding so that you don't
661 get warnings during compilation. Also to call the method of the parent
662 class, you can use the PARENT_HANDLER macro with your arguments. Example:
665 override (Gtk:Container) void
666 add (Gtk:Container *self (check null type), Gtk:Widget *wid (check null type))
669 PARENT_HANDLER(self, wid);
673 If the function has a return value, then PARENT_HANDLER is an expression that
674 you can use. It will return whatever the parent handler returned, or the
675 "onerror" expression if there was no parent handler.
679 Inside the code, aliases are set for the methods, so that you don't
680 have to type the class name before each call, just the name of the method.
693 return foo(self) + i;
698 Underscore removal (0.93.5+):
700 Sometimes this causes conflicts with other libraries. For example a library
701 might have already used the identifier foo. You can prepend an underscore to
702 the name in the .gob file. This will make the local short alias have an
703 initial underscore, but it will not change the name of the actual name of the
704 function. For example:
706 class My:Object from Gtk:Object {
713 /* short calling convention */
715 /* long calling convention */
720 Thus you see that the "_foo" method still generates the method "my_object_foo"
721 just as "foo" would generate. You can turn off this behavior if you depend
722 on the old (pre 0.93.5) behavior with the --no-kill-underscores option. This
723 also means that if both "_foo" and "foo" are defined, it is treated as a
726 This does not apply to override methods. Override methods are special beasts
727 and this is not necessary and would make the code behave in weird ways.
731 You should define a new method which should be a normal public method. Inside
732 this method, you can use the GET_NEW macro that is defined for you and that
733 will fetch a new object, so a fairly standard new method would look like:
739 ret = GTK_OBJECT (GET_NEW);
747 There are some standard casts defined for you. Instead of using the full
748 macros inside the .c file, you can use SELF, IS_SELF and SELF_CLASS. Using
749 these makes it easier to for example change class names around.
753 Since 0.93.5, there have also been defined the Self and SelfClass types inside
754 your .c file. These serve the same function as the above, they make it easier
755 to type and easier to change typenames around which can help a lot during
756 prototyping stage. However you should note that the Self type should not be
757 used in function prototypes as one of the arguments or as a return value type.
758 This is because this is a simple C typedef which is only available inside you
759 .c file. You can disable both the self casting macros and the self type
760 aliases by passing --no-self-alias to
762 .SH DEALING WITH DIFFERENT GOB VERSIONS
766 In your generated C file, you can use the defines GOB_VERSION_MAJOR
767 GOB_VERSION_MINOR and GOB_VERSION_PATCHLEVEL if you wish to for example
768 use a feature that is only available in some newer gob version. Note however
769 that you can only use these defines in the C code portions of your .gob file,
770 and #ifdef's cannot span multiple functions. Check the BUGS section
771 for more on using the C preprocessor and gob. Also note that these
772 have only been available since the 0.92.1 version of gob.
774 Minimum version requires:
776 You can also make your .gob file require at least certain version of gob. You
777 do this by putting 'requires x.y.z' (where x.y.z is the version number) outside
778 of any C block, comment or class, usually you should make this the first line
779 in the file or close to the top. If gob finds this and the version of gob used
780 to compile the code is lower then that listed in the require, gob will generate
781 an error and exit. For example to require that gob version 0.92.1 or higher
782 be used to compile a file, put this at the top of that file:
788 It should be noted however that this feature was not added until 0.92.1, and
789 so if the file gets compiled by a lower version, gob would generate a
790 syntax error. Thus by putting in a requires line, you are implicitly
791 requiring at least 0.92.1.
795 There is a C++ mode so that gob creates C++ compiler friendly files. You need
796 to use the --for-cpp argument to gob. This will make the generated file have
797 a .cc instead of a .c extension, and several things will be adjusted to
798 make it all work for a C++ compiler. One thing that will be missing is an
799 alias to the new method, as that clashes with C++, so instead you'll have to
800 use the full name of the method inside your code. Also note that gob does
801 not use any C++ features, this option will just make the generated code
802 compile with a C++ compiler.
804 .SH IDENTIFIER CONFLICTS
806 Gob will need to define some local variables and functions in the generated
807 files, so you need to take some precaution not to conflict with these. The
808 general rule of thumb is that all of these start with three underscores. There
809 is one, "parent_class" which doesn't because it's intended for use in your
810 code. For virtuals or signals, you cannot use the identifier __parent__
811 which is used for the parent of the object. You should actually never access
812 __parent__ either as it not guaranteed that it will stay named this way.
813 Data members cannot be named __parent__ nor _priv. For methods, you cannot
814 use the identifiers "init" or "class_init" unless you mean the constructor
815 methods. You shouldn't generally use 3 underscores even in override method
816 argument lists and virtual and signal method names as it might confuse the
817 PARENT_HANDLER macro. In fact avoiding all names with three underscores is
818 the best policy when working with gob.
820 Also note that starting with version 0.93.5, method names that start with a
821 an underscore are equivalent to the names without the initial underscore. This
822 is done to avoid conflicts with the aliases. Thus you can define the method
823 as "_name", if "name" happens to be some standard library function. This is
824 the same as defining it as "name" except that the local alias will be "_name"
827 There are a couple of defines which you shouldn't be redefining in the code
828 or other headers. These are SELF, IS_SELF, SELF_CLASS, ARG, VAR,
829 PARENT_HANDLER, GET_NEW, GOB_VERSION_MAJOR, GOB_VERSION_MINOR and
830 GOB_VERSION_PATCHLEVEL.
832 As for types, there are Self and SelfClass types which are only defined in your
833 source files. Their generation (just like the generation of the SELF macros)
834 can be turned off, see command line options.
836 .SH USING GTK-DOC STYLE INLINE DOCUMENTATION
838 If you want to use gtk-doc style inline documentation for your objects, you
839 can do one of two things. First, you could include the inline documentation
840 comments in your %{ %} section which will then be put verbatim into the
841 output source file. This is the way you should use for functions you define
842 outside of the class.
844 For class methods, you should use a gtk+ style comment, however it can be
845 indented any number of tabs or spaces and you can use the short method name
846 without the type prefix. Gob will automatically try to extract these and
847 translate to full names and put them in the output source file. An example
851 class Gtk:Button:Example from Gtk:Button {
855 * Makes a new #GtkButtonExample widget
857 * Returns: a new widget
863 return GTK_WIDGET(GET_NEW);
868 If the function you are documenting is a signal or a virtual then it will
869 be documenting the wrapper that starts that virtual function or emits
872 .SH DEALING WITH CIRCULAR HEADERS
874 Sometimes you may need to use an object of type MyObjectA in the MyObjectB
875 class and vice versa. Obviously you can't include headers for both. So you
876 need to just declare the typedef in the header of A for B, and the other way
877 around as well. The headers generated since v0.92.2 include a protecting
878 define before it declares the typedef. This define is the
879 __TYPEDEF_<upper case object name>__. So inside my-object-a.h there will be
883 #ifndef __TYPEDEF_MY_OBJECT_A__
884 #define __TYPEDEF_MY_OBJECT_A__
885 typedef struct _MyObjectA MyObjectA;
889 Now instead of including my-object-a.h in the header section of
890 my-object-b.gob, just copy the above code there and you're set for using
891 MyObjectA as a type in the method parameters and public types.
893 Another way to get out of this problem is if you can use those types only
894 in the private members, in which case they won't be in the generated public
897 .SH BUILDING WITH MAKE
899 If you are using normal makefiles, what you need to do is to add a generic
900 rule for .gob files. So you would include the following in the Makefile
901 and then just use the .c and .h files as usual (make sure the space
902 before the 'gob' is a tab, not spaces):
905 %.c %.h %-private.h: %.gob
910 .SH BUILDING WITH AUTOCONF and AUTOMAKE
912 This is a little bit more involved. Basically the first thing to do is to
913 check for GOB in your configure.in file. You can use the supplied m4 macro
914 which will also check the version of gob. Basically you include this:
920 This will replace @GOB@ in your makefiles with the full path of gob. Thus
921 when adding the generic rule to your Makefile.am file, it should look like:
924 %.c %.h %-private.h: %.gob
929 For Makefile.am you have to set up a couple more things. First you have to
930 include the generated .c and .h files into BUILT_SOURCES variable. You
931 have to include both the .gob and the .c and .h files in the SOURCES for your
936 The lexer does not actually parse the C code, so I'm sure that some corner
937 cases or maybe even some not so corner cases of C syntax might confuse gob
938 completely. If you find any, send me the source that makes it go gaga and I'll
939 try to make the lexer try to handle it properly, but no promises.
941 Another thing is that gob ignores preprocessor macros. Since gob counts
942 braces, the following code won't work:
954 To make this work, you'd have to do this:
967 There is no real good way we can handle this without parsing C code, so we
968 probably never will. In the future, I might add #if 0 as a comment but
969 that's about as far as I can really take it and even that is problematic.
970 Basically, if you use gob, just don't use the C preprocessor too extensively.
972 Comments will not get through to the generated files unless inside C code.
973 This makes using something like gtk-doc harder. However I'm planning to
976 The short name aliases are actually implemented as pointers to functions. Thus
977 if you want to get the pointer of a function using the short name alias you
978 can't use the '&'. Thus:
983 /* this will NOT work */
989 /* Both of these will work */
990 foo = &my_class_long_name;
991 foo = my_class_long_name;
997 George Lebl <jirka@5z.com>
projects / gob-dx.git / blob