Re: [PATCH 3/4] qemu-io-cmds: avoid gcc 10 warning

[Dr. David Alan Gilbert]

* Christian Borntraeger (borntraeger@de.ibm.com) wrote:
> With gcc 10 on Fedora32 I do get:
> 
> Compiling C object libblock.fa.p/qemu-io-cmds.c.o
> In file included from /usr/include/stdio.h:867,
>                  from /home/cborntra/REPOS/qemu/include/qemu/osdep.h:85,
>                  from ../qemu-io-cmds.c:11:
> In function ‘printf’,
>     inlined from ‘help_oneline’ at ../qemu-io-cmds.c:2389:9,
>     inlined from ‘help_all’ at ../qemu-io-cmds.c:2414:9,
>     inlined from ‘help_f’ at ../qemu-io-cmds.c:2424:9:
> /usr/include/bits/stdio2.h:107:10: error: ‘%s’ directive argument is null 
> [-Werror=format-overflow=]
>   107 |   return __printf_chk (__USE_FORTIFY_LEVEL - 1, __fmt, __va_arg_pack 
> ());
>       |          
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> cc1: all warnings being treated as errors
> 
> Let us check for null.
> 
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

I'd already posted
'qemu-io-cmds: Simplify help_oneline' that simplifies
this function much more; Kevin picked that up for the block branch a
couple of days ago.

Dave


> ---
>  qemu-io-cmds.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
> index baeae86d8c85..c2080aa398a9 100644
> --- a/qemu-io-cmds.c
> +++ b/qemu-io-cmds.c
> @@ -2386,7 +2386,9 @@ static void help_oneline(const char *cmd, const 
> cmdinfo_t *ct)
>      if (cmd) {
>          printf("%s ", cmd);
>      } else {
> -        printf("%s ", ct->name);
> +        if (ct->name) {
> +            printf("%s ", ct->name);
> +        }
>          if (ct->altname) {
>              printf("(or %s) ", ct->altname);
>          }
> -- 
> 2.26.2
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK