Re: [PATCH] Fix build warnings in resolv/res_send.c

[Stefan Liebler <stli at linux dot ibm dot com>]

On 6/25/19 3:18 PM, Stefan Liebler wrote:
> Hi,
>
> this patch fixes the gcc warnings seen with gcc 9 -march>=z13 on s390x:
> res_send.c: In function ‘__res_context_send’:
> res_send.c:498:7: error: ‘resplen’ may be used uninitialized in this 
> function [-Werror=maybe-uninitialized]
>    498 |    if (n == 0 && (buf2 == NULL || *resplen2 == 0))
>        |       ^
>
> In this case send_vc is inlined into __res_context_send
> and the maybe uninitialized resplen belongs to the one in send_vc.
>
> In send_vc there is already a DIAG_IGNORE_NEEDS_COMMENT (5, 
> "-Wmaybe-uninitialized")
> and a comment which explains that this is a false-positive.
> Note that resplen is used as return value.
>
> This patch adds a further DIAG_IGNORE_NEEDS_COMMENT around the 
> declaration of n
> in __res_context_send and the comparison after n was set to the return 
> value of send_vc.
>
> Bye
> Stefan
>
> ChangeLog:
>
>      * resolv/res_send.c (__res_context_send):
>      Disable maybe-uninitialized warning.

ping