Re: How to look up where a structure is defined?

[Konstantin Kharlamov <hi-angel@yandex.ru>]

On Wed, 2021-03-03 at 16:46 -0600, Peng Yu wrote:
> On 3/3/21, Konstantin Kharlamov <hi-angel@yandex.ru> wrote:
> > On Wed, 2021-03-03 at 16:24 -0600, Peng Yu wrote:
> > > 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
> 
> ctags only shows the above. The following is what I show where the
> declaration is.

Ah, I see. Okay, so, I think including declarations by default is disabled, you probably need to enable it. There're various options on what to include in the tags file, see `ctags --list-kinds-full`, and then using an option kinda like `--kinds-C=+px` (p and x are letters from the --list-kinds-full) should work.