Re: [PATCH 06/13] string: Implement strerror in terms of strerror_l

[Florian Weimer via Libc-alpha <libc-alpha@sourceware.org>]

> diff --git a/string/strerror.c b/string/strerror.c
> index 283ab70f91..35c749016e 100644
> --- a/string/strerror.c
> +++ b/string/strerror.c
> @@ -15,29 +15,11 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>  
> -#include <libintl.h>
> -#include <stdio.h>
>  #include <string.h>
> -#include <errno.h>
> -
> -/* Return a string describing the errno code in ERRNUM.
> -   The storage is good only until the next call to strerror.
> -   Writing to the storage causes undefined behavior.  */
> -libc_freeres_ptr (static char *buf);
> +#include <locale/localeinfo.h>
>  
>  char *
>  strerror (int errnum)
>  {
> -  char *ret = __strerror_r (errnum, NULL, 0);
> -  int saved_errno;
> -
> -  if (__glibc_likely (ret != NULL))
> -    return ret;
> -  saved_errno = errno;
> -  if (buf == NULL)
> -    buf = malloc (1024);
> -  __set_errno (saved_errno);
> -  if (buf == NULL)
> -    return _("Unknown error");
> -  return __strerror_r (errnum, buf, 1024);
> +  return __strerror_l (errnum, __libc_tsd_get (locale_t, LOCALE));
>  }

Why is it okay to share the buffer between strerror and strerror_l?
POSIX is a bit unclear about this.  Practically speaking, it should be
okay.  But perhaps there should be a NEWS entry.

Thanks,
Florian