On Thu, 15 Nov 2018 08:19:56 +0100, Kirill Marinushkin wrote:
Before this commit, compilation of `pcm_share` causes warnings "ignoring return value" for several `read` and `write` operations:
pcm_share.c: In function '_snd_pcm_share_missing': pcm_share.c:293:5: warning: ignoring return value of 'read', declared with attribute warn_unused_result [-Wunused-result] read(share->slave_socket, buf, 1); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ <...>However, ignoring return values in these use-cases is safe and optimal, because `read` and `write` operations are executed upon descriptors, created with `socketpair()` and `pipe()`.
This commit fixes the warnings by introducing the return value with the attribute `unused` (for details, see [1]). The macro, used in this commit, is defined at `global.h`:
define ATTRIBUTE_UNUSED __attribute__ ((__unused__))I explicitly checked the objdump: this commit doesn't change the machine code, related to the modified C code lines. The execution performance is not affected.
[1] https://gcc.gnu.org/onlinedocs/gcc-8.2.0/gcc/Common-Variable-Attributes.html
Signed-off-by: Kirill Marinushkin kmarinushkin@birdec.tech
Which compiler version? I'm using gcc 8.2.1, and couldn't get any warnings like the above.
thanks,
Takashi