在 2025/1/15 23:33, Zorro Lang 写道:
On Mon, Jan 06, 2025 at 05:59:06PM +0800, Shiyang Ruan wrote:
When build xfstests, a lot of "unused result" warning are reported:
[CC] write_log.lo
write_log.c: In function 'wlog_record_write':
write_log.c:205:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result]
205 | write(wfile->w_afd, wbuf, reclen);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
write_log.c:209:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result]
209 | write(wfile->w_rfd, wbuf, reclen);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[CC] random.lo
Hi,
I never hit this build warning:
# make
...
Building lib
[LTDEP]
[CC] write_log.lo
[LD]
Building ltp
[CC] doio
[CC] fsstress
...
Besides that ...
Could you share me the info of your build environment? Such as OS,
kernel, gcc version. I'd like to find out what wrong with mine.
--
Thanks,
Ruan.
Mostly are calused by not using the return value of read()/write()/...
Ignore this warning by adding `-Wno-unused-result` to CCFLAGS. This
won't cause other problem but make the log clean.
Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
---
include/builddefs.in | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/builddefs.in b/include/builddefs.in
index 7274cde8d..edf87ff00 100644
--- a/include/builddefs.in
+++ b/include/builddefs.in
@@ -75,7 +75,7 @@ HAVE_RLIMIT_NOFILE = @have_rlimit_nofile@
NEED_INTERNAL_XFS_IOC_EXCHANGE_RANGE = @need_internal_xfs_ioc_exchange_range@
HAVE_FICLONE = @have_ficlone@
-GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall
+GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall -Wno-unused-result
I'm not an expert of gcc. From the manual of gcc, it says:
-Wno-unused-result
Do not warn if a caller of a function marked with attribute "warn_unused_result" does not use its return value. The default is -Wunused-result.
Looks like the "-Wno-unused-result" works for "a function marked with
attribute warn_unused_result", e.g.
int __attribute__((warn_unused_result)) foo(void)
I think fstests doesn't use that attribute.
Thanks,
Zorro
ifeq ($(PKG_PLATFORM),linux)
PCFLAGS = -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 $(GCCFLAGS)
--
2.43.0
