> On 25-Jan-2022, at 9:38 AM, Kris Andersen via Gcc <gcc@gcc.gnu.org> wrote:
>
> The %m format specifier is a documented feature of syslog, but gcc gives a
> warning when -Wpedantic is used. Is this a bug?
>
> For example, the program:
>
> #include <syslog.h>
> int main(void)
> {
> syslog(LOG_ERR, "%m");
> return 0;
> }
>
> gives:
> warning: ISO C does not support the ‘%m’ gnu_printf format [-Wformat=]
I think, the compiler is correct by complaining about it when strict
warnings are enabled.
according to GNU documentation
(http://www.gnu.org/software/libc/manual/html_node/Other-Output-Conversions.html)
“ The ‘%m’ conversion is a GNU C Library extension “
>
> when compiled[1] with
> gcc -Wall -Wextra -Wpedantic -o test test.c
>
> The man page for syslog(3) states that %m is supported: "the two-character
> sequence %m will be replaced by the error message string strerror(errno)."
>
> Submitting a bug report for this feels like arguing that the answer in the
> back of the book is wrong (...rarely the right move). What am I missing
> here?
FWIW, A bug report requesting support for __format__ attribute for
syslog is already filed as bug 15338 (
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=15338 )
Thanks
- Ankur
