How to look up where a structure is defined?

[Peng Yu]

On Wed, Mar 3, 2021 at 2:23 PM Konstantin Kharlamov <hi-angel@yandex.ru> wrote:
>
> On Wed, 2021-03-03 at 23:09 +0300, Konstantin Kharlamov wrote:
> > On Wed, 2021-03-03 at 13:51 -0600, Peng Yu wrote:
> > > This seems to be a complicated solution. I just want to get a database
> > > (a TSV file should be fine) of types and the header they appear. I
> > > don't want to build the project just to get this info.
> >
> > I see, well, the Universal Ctags I mentioned should work for you. It doesn't
> > require building the project: you just run `ctags -R` or `ctags -Re` (first
> > for
> > vim-style tags file, second one for emacs-style) over the repository, and you
> > get a `tags` or `TAGS` file with a list of definitions.
> >
> > Possible drawbacks on ctags I mentioned in the other email. Basically it's
> > that
> > it doesn't take context into consideration.
> >
> > Regarding usage: the tags file it generates, although can be read for human,
> > supposed to be read by text editors/IDEs. Since you mention a CSV file, I
> > assume
> > you might want something human-readable. Please see option --output-format= in
> > `man ctags` for details: I think you might want the `xref` format. (I never
> > tried it myself, just reading the man it seems like it what you're after).
>
> Although, I wouldn't hold my breath that reading a resulting xref file would be easy The reason being is that I expect a tags file created from glibc repo to be some hundreds of megabytes. For reference, a TAGS file I generated long ago for libreoffice project is sized at 183M.
>
> So yeah, you will probably want to use the file from an IDE or text editor, rather than reading it manually.

ctags can partially solve the problem. The declaration and definition
of a struct are all in the header. So finding the definition is OK.
But it can not return function declaration. Is there a way to show
function declaration as well? (For example, ./socket/sys/socket.h for
setsockopt().)

$ grep '^icmphdr\>' tags
icmphdr sysdeps/gnu/netinet/ip_icmp.h /^struct icmphdr$/;" s
$ grep ^setsockopt tags
setsockopt sysdeps/unix/sysv/linux/setsockopt.c /^setsockopt (int fd,
int level, int optname, const void *optval, socklen_t len)$/;" f

./socket/sys/socket.h
215:extern int setsockopt (int __fd, int __level, int __optname,

-- 
Regards,
Peng