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[v3,3/3] selftests/futex: pass _GNU_SOURCE without a value to the compiler

Message ID 20240531200755.128749-4-jhubbard@nvidia.com (mailing list archive)
State Accepted
Headers show
Series selftests/futex: clang-inspired fixes | expand

Commit Message

John Hubbard May 31, 2024, 8:07 p.m. UTC 
It's slightly better to set _GNU_SOURCE in the source code, but if one
must do it via the compiler invocation, then the best way to do so is
this:

    $(CC) -D_GNU_SOURCE=

...because otherwise, if this form is used:

    $(CC) -D_GNU_SOURCE

...then that leads the compiler to set a value, as if you had passed in:

    $(CC) -D_GNU_SOURCE=1

That, in turn, leads to warnings under both gcc and clang, like this:

    futex_requeue_pi.c:20: warning: "_GNU_SOURCE" redefined

Fix this by using the "-D_GNU_SOURCE=" form.

Reviewed-by: Edward Liaw <edliaw@google.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 tools/testing/selftests/futex/functional/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/tools/testing/selftests/futex/functional/Makefile b/tools/testing/selftests/futex/functional/Makefile
index a392d0917b4e..994fa3468f17 100644
--- a/tools/testing/selftests/futex/functional/Makefile
+++ b/tools/testing/selftests/futex/functional/Makefile
@@ -1,6 +1,6 @@ 
 # SPDX-License-Identifier: GPL-2.0
 INCLUDES := -I../include -I../../ $(KHDR_INCLUDES)
-CFLAGS := $(CFLAGS) -g -O2 -Wall -D_GNU_SOURCE -pthread $(INCLUDES) $(KHDR_INCLUDES)
+CFLAGS := $(CFLAGS) -g -O2 -Wall -D_GNU_SOURCE= -pthread $(INCLUDES) $(KHDR_INCLUDES)
 LDLIBS := -lpthread -lrt
 
 LOCAL_HDRS := \