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I can successfully create a tags file for vim with exctags (Exuberant Ctags).

However, creating tags allowing to jump to the prototype of a function does not work, due the system headers using a syntax-mangling macro of the form

#define _EXFUN(name, proto) name proto

and in, e.g. string.h using

char *_EXFUN(strchr,(const char *, int));

which creates a tag for _EXFUN instead of strchr:

_EXFUN /somedir/include/string.h /^char *_EXFUN(strchr,(const char *, int));$/;" p

I create tags with this command:

exctags -f tags.p --language-force=c --c-kinds=p file1 file2 ...

I've read the exctags man page up and down, tried various -I options to affect macro expansions but to no avail. Has anyone solved this?

To handle that particular macro, you could use the --regex-<LANG> option:

ctags --regex-c='/^[^#]*_EXFUN *( *([^ ,]+),.*/1/p/' ...

Which generates a tags file with:

_EXFUN test.c 1;" d file:
strchr test.c /^char *_EXFUN(strchr,(const char *, int));$/;" p

Run ectags on the preprocessed file, and ask it to look at the preprocessor's comments (--line-directives=yes) and to write line numbers into the tags file (-n or --excmd=numbers).

cc -E prog.c >prog.p
ectags --line-directives=yes --language-force=c --c-kinds=p -n prog.p

Sample C file:

#define _EXFUN(name, proto) name proto

char *_EXFUN(strchr,(const char *, int));

Resulting tags file:

!_TAG_FILE_FORMAT 2 /extended format; --format=1 will not append ;" to lines/
!_TAG_FILE_SORTED 1 /0=unsorted, 1=sorted, 2=foldcase/
!_TAG_PROGRAM_AUTHOR Darren Hiebert /dhiebert@users.sourceforge.net/
!_TAG_PROGRAM_NAME Exuberant Ctags //
!_TAG_PROGRAM_URL http://ctags.sourceforge.net /official site/
!_TAG_PROGRAM_VERSION 5.8 //
strchr prog.c 3;" p file:

As you can see, the prototype for strchr is listed as occurring on line 3 in prog.c.

The downside with this is that you don't get any tag entries for preprocessing macros.

You can solve that through running ectags on both the preprocessed and original files though:

ectags --line-directives=yes --language-force=c --c-kinds=pd -n -I _EXFUN prog.p prog.c

which produces

[...]
_EXFUN prog.c 1;" d file:
strchr prog.c 3;" p file: