v4l2-ctl: fix compiler warning

v4l2-ctl-streaming.cpp: In function ‘__u32 read_u32(FILE*)’:
v4l2-ctl-streaming.cpp:434:7: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result]
fread(&v, 1, sizeof(v), f);
     ^

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reported-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/utils/v4l2-ctl/v4l2-ctl-streaming.cpp b/utils/v4l2-ctl/v4l2-ctl-streaming.cpp
index da25e0d2..31670738 100644
--- a/utils/v4l2-ctl/v4l2-ctl-streaming.cpp
+++ b/utils/v4l2-ctl/v4l2-ctl-streaming.cpp
@@ -431,7 +431,8 @@ static __u32 read_u32(FILE *f)
 {
 	__u32 v;
 
-	fread(&v, 1, sizeof(v), f);
+	if (fread(&v, 1, sizeof(v), f) != sizeof(v))
+		return 0;
 	return ntohl(v);
 }