[Qemu-devel] Re: [PATCH] block: Use GCC_FMT_ATTR and fix a format error

[Blue Swirl]

On Thu, Sep 23, 2010 at 6:37 PM, Stefan Weil <address@hidden> wrote:
> Adding the gcc format attribute detects a format bug
> which is fixed here.
>
> Cc: Blue Swirl <address@hidden>
> Cc: Kevin Wolf <address@hidden>
> Signed-off-by: Stefan Weil <address@hidden>
> ---
>  block/blkverify.c |    5 +++--
>  1 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/block/blkverify.c b/block/blkverify.c
> index 8083464..b39fb67 100644
> --- a/block/blkverify.c
> +++ b/block/blkverify.c
> @@ -53,7 +53,8 @@ static AIOPool blkverify_aio_pool = {
>     .cancel             = blkverify_aio_cancel,
>  };
>
> -static void blkverify_err(BlkverifyAIOCB *acb, const char *fmt, ...)
> +static void GCC_FMT_ATTR(2, 3) blkverify_err(BlkverifyAIOCB *acb,
> +                                             const char *fmt, ...)
>  {
>     va_list ap;
>
> @@ -300,7 +301,7 @@ static void blkverify_verify_readv(BlkverifyAIOCB *acb)
>     ssize_t offset = blkverify_iovec_compare(acb->qiov, &acb->raw_qiov);
>     if (offset != -1) {
>         blkverify_err(acb, "contents mismatch in sector %ld",
> -                      acb->sector_num + (offset / BDRV_SECTOR_SIZE));
> +                      (long)(acb->sector_num + (offset / BDRV_SECTOR_SIZE)));

sector_num is int64_t, so the correct fix is to change '%ld' to '%" PRId64'.