On 5/15/20 9:40 AM, Guoqing Jiang wrote:
> Got below error when run "make everything".
>
> restripe.c: In function ‘test_stripes’:
> restripe.c:870:4: error: ignoring return value of ‘read’, declared with attribute warn_unused_result [-Werror=unused-result]
> read(source[i], stripes[i], chunk_size);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Fix it by set the return value of ‘read’ to diskP, which should be
> harmless since diskP will be set again before it is used.
>
> Signed-off-by: Guoqing Jiang <guoqing.jiang@xxxxxxxxxxxxxxx>
> ---
> restripe.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/restripe.c b/restripe.c
> index 31b07e8..21c90f5 100644
> --- a/restripe.c
> +++ b/restripe.c
> @@ -867,7 +867,11 @@ int test_stripes(int *source, unsigned long long *offsets,
>
> for (i = 0 ; i < raid_disks ; i++) {
> lseek64(source[i], offsets[i]+start, 0);
> - read(source[i], stripes[i], chunk_size);
> + /*
> + * To resolve "ignoring return value of ‘read’", it
> + * should be harmless since diskP will be again later.
> + */
> + diskP = read(source[i], stripes[i], chunk_size);
It doesn't complain on Fedora 32, however checking the return value of
lseek64 and read is a good thing.
However what you have done is to just masking the return value and
throwing it away, is not OK. Please do it properly.
Thanks,
Jes
