Re: [PATCH] fstests: fix blksize_t printf format warnings across architectures

["Darrick J. Wong" <djwong@kernel.org>]

On Thu, Nov 21, 2024 at 08:36:58AM +1030, Qu Wenruo wrote:
> 
> 
> 在 2024/11/20 22:10, Anand Jain 写道:
> > Fix format string warnings when printing blksize_t values that vary
> > across architectures. The warning occurs because blksize_t is defined
> > differently between architectures: aarch64 architectures blksize_t is
> > int, on x86-64 it's long-int.  Cast the values to long. Fixes warnings
> > as below.
> > 
> >   seek_sanity_test.c:110:45: warning: format '%ld' expects argument of type
> >   'long int', but argument 3 has type 'blksize_t' {aka 'int'}
> > 
> >   attr_replace_test.c:70:22: warning: format '%ld' expects argument of type
> >   'long int', but argument 3 has type '__blksize_t' {aka 'int'}
> 
> Why not just use %zu instead?

From printf(3):

       z      A  following  integer conversion corresponds to a size_t
              or ssize_t argument, or a following n conversion  corre‐
              sponds to a pointer to a size_t argument.

blksize_t is not a ssize_t.

--D

> Thanks,
> Qu
> 
> > 
> > Signed-off-by: Anand Jain <anand.jain@oracle.com>
> > ---
> >   src/attr_replace_test.c | 2 +-
> >   src/seek_sanity_test.c  | 2 +-
> >   2 files changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/src/attr_replace_test.c b/src/attr_replace_test.c
> > index 1218e7264c8f..5d560a633361 100644
> > --- a/src/attr_replace_test.c
> > +++ b/src/attr_replace_test.c
> > @@ -67,7 +67,7 @@ int main(int argc, char *argv[])
> >   	if (ret < 0) die();
> >   	size = sbuf.st_blksize * 3 / 4;
> >   	if (!size)
> > -		fail("Invalid st_blksize(%ld)\n", sbuf.st_blksize);
> > +		fail("Invalid st_blksize(%ld)\n", (long)sbuf.st_blksize);
> >   	size = MIN(size, maxsize);
> >   	value = malloc(size);
> >   	if (!value)
> > diff --git a/src/seek_sanity_test.c b/src/seek_sanity_test.c
> > index a61ed3da9a8f..c5930357911f 100644
> > --- a/src/seek_sanity_test.c
> > +++ b/src/seek_sanity_test.c
> > @@ -107,7 +107,7 @@ static int get_io_sizes(int fd)
> >   		offset += pos ? 0 : 1;
> >   	alloc_size = offset;
> >   done:
> > -	fprintf(stdout, "Allocation size: %ld\n", alloc_size);
> > +	fprintf(stdout, "Allocation size: %ld\n", (long)alloc_size);
> >   	return 0;
> > 
> >   fail:
> 
>