During porting libbpf to bcc, I got some warnings like below:
...
[ 2%] Building C object
src/cc/CMakeFiles/bpf-shared.dir/libbpf/src/libbpf.c.o
/home/yhs/work/bcc2/src/cc/libbpf/src/libbpf.c:12:0:
warning: "_GNU_SOURCE" redefined [enabled by default]
#define _GNU_SOURCE
...
[ 3%] Building C object
src/cc/CMakeFiles/bpf-shared.dir/libbpf/src/libbpf_errno.c.o
/home/yhs/work/bcc2/src/cc/libbpf/src/libbpf_errno.c: In function
‘libbpf_strerror’:
/home/yhs/work/bcc2/src/cc/libbpf/src/libbpf_errno.c:45:7:
warning: assignment makes integer from pointer without a cast [enabled by
default]
ret = strerror_r(err, buf, size);
...
bcc is built with _GNU_SOURCE defined and this caused the above warning.
This patch intends to make libpf _GNU_SOURCE friendly by
. define _GNU_SOURCE in libbpf.c unless it is not defined
. undefine _GNU_SOURCE as non-gnu version of strerror_r is expected.
Signed-off-by: Yonghong Song <y...@fb.com>
---
tools/lib/bpf/libbpf.c | 2 ++
tools/lib/bpf/libbpf_errno.c | 1 +
2 files changed, 3 insertions(+)
Changelog:
v1 -> v2:
. undef _GNU_SOURCE instead of multiversioning strerror_r,
suggested by Jakub.
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index ed4212a4c5f9..59b748ebd15f 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9,7 +9,9 @@
* Copyright (C) 2017 Nicira, Inc.
*/
+#ifndef _GNU_SOURCE
#define _GNU_SOURCE
+#endif
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
diff --git a/tools/lib/bpf/libbpf_errno.c b/tools/lib/bpf/libbpf_errno.c
index d83b17f8435c..4343e40588c6 100644
--- a/tools/lib/bpf/libbpf_errno.c
+++ b/tools/lib/bpf/libbpf_errno.c
@@ -7,6 +7,7 @@
* Copyright (C) 2017 Nicira, Inc.
*/
+#undef _GNU_SOURCE
#include <stdio.h>
#include <string.h>
--
2.17.1
