在 2025/1/17 12:01, Zorro Lang 写道:
On Thu, Jan 16, 2025 at 05:55:49PM +0800, Shiyang Ruan wrote:
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.
Do you use gcc-15?
I'm using gcc v13, installed from Ubuntu 24.04's apt.
$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-linux-gnu/13/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ...
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 13.3.0 (Ubuntu 13.3.0-6ubuntu2~24.04)
--
Thanks,
Ruan.
--
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
