Re: Add restrict annotations to all functions that require it

[Alejandro Colomar via Libc-alpha <libc-alpha@sourceware.org>]

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[CC += all CCs from man-pages patches]

Hi Seija,

On 11/27/22 01:56, Seija K. via Libc-alpha wrote:
> The format value has to be a string literal, every time. Otherwise, you are
> not using these functions correctly. To reinforce this fact, I put
> __restrict over every example of this I could find.


I like this change.  In fact, when I added 'restrict' to the Linux man-pages, I 
had to check that in some cases POSIX and glibc matched, but in others, either 
glibc or POSIX had restrict while the other didn't:

Linux man-pages commits:

-  746d60af802a4462055c4f87a62681f7254325d8 [strptime(3)]
    -  You fixed this one in the patch; fine.
-  0864c240797e3b793a88ee6be5710dd9a8df9b45 [posix_spawnp(3)]
    -  This one hasn't been changed in you patch; please check.
    -  Bug reported here: <https://sourceware.org/bugzilla/show_bug.cgi?id=27529>
    -  See some proof below.
-  c445280cf371cda66916c4e5e0fdb168db3a5ad6 [lio_listio(3)]
    -  This one hasn't been changed in you patch; please check.
    -  Bug reported here: <https://sourceware.org/bugzilla/show_bug.cgi?id=16747>
    -  See some proof below.

I might have missed other cases by accident, but I think those 3 are all the 
cases where POSIX uses restrict and glibc doesn't (there are many more cases of 
the opposite, but that's OK for your patch), as far as I documented back then 
when I added restrict to the man-pages.

Cheers,

Alex

P.S.: I'm neutral to having the 'restrict' keyword in function definitions, if 
they are already in function prototypes (Mike reported this).

--- posix_spawnp(3):

$ man 3p posix_spawnp |sed -n '/^SYNOPSIS/,/;/p'
SYNOPSIS
        #include <spawn.h>

        int posix_spawnp(pid_t *restrict pid, const char *restrict file,
            const posix_spawn_file_actions_t *file_actions,
            const posix_spawnattr_t *restrict attrp,
            char *const argv[restrict], char *const envp[restrict]);
$ grepc posix_spawnp /usr/include
/usr/include/spawn.h:85:
extern int posix_spawnp (pid_t *__pid, const char *__file,
			 const posix_spawn_file_actions_t *__file_actions,
			 const posix_spawnattr_t *__attrp,
			 char *const __argv[], char *const __envp[])
     __nonnull ((2, 5));

--- lio_listio(3):

$ man 3p lio_listio |sed -n '/^SYNOPSIS/,/;/p'
SYNOPSIS
        #include <aio.h>

        int lio_listio(int mode, struct aiocb *restrict const list[restrict],
            int nent, struct sigevent *restrict sig);
$ grepc lio_listio /usr/include
/usr/include/aio.h:148:
extern int lio_listio (int __mode,
		       struct aiocb *const __list[__restrict_arr],
		       int __nent, struct sigevent *__restrict __sig)
   __THROW __nonnull ((2));


/usr/include/aio.h:214:
#  define lio_listio lio_listio64
-- 
<http://www.alejandro-colomar.es/>

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