2023-01-21 20:37:50

by Eric Biggers

[permalink] [raw]
Subject: [PATCH 10/38] lib/blkid: suppress -Wunused-result warning in blkid_flush_cache()

From: Eric Biggers <[email protected]>

When _FORTIFY_SOURCE is defined, glibc annotates link() with the
warn_unused_result function attribute. With gcc, that makes
'(void) link()' cause a -Wunused-result warning, despite the explicit
cast to void. That's annoying, since the use case in lib/blkid/save.c
is legitimate (opportunistic backup). So let's suppress this warning.

Signed-off-by: Eric Biggers <[email protected]>
lib/blkid/save.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/lib/blkid/save.c b/lib/blkid/save.c
index 036f07a4a..6f4499cfd 100644
--- a/lib/blkid/save.c
+++ b/lib/blkid/save.c
@@ -154,7 +154,15 @@ int blkid_flush_cache(blkid_cache cache)
if (backup) {
sprintf(backup, "%s.old", filename);
+#if defined(__GNUC__) && __GNUC__ >= 5
+/* explicit (void) cast is not enough with glibc and _FORTIFY_SOURCE */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-result"
(void) link(filename, backup);
+#if defined(__GNUC__) && __GNUC__ >= 5
+#pragma GCC diagnostic pop
if (rename(opened, filename) < 0)