[FFmpeg-devel] [PATCH 1/3] avcodec/cbs_h266_syntax_template: Don't omit unused function parameter

[Andreas Rheinhardt]

The calls to the sei_decoded_picture_hash read and write functions
are performed with four pointer arguments; just because one
of them is unused by the callees does not mean that they
can be omitted: This is undefined behaviour.
(This was not recognized because the SEI_MESSAGE_RW macro
contains casts.)

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
---
I found this via UBSan test failures with Clang 17,
but actually there are compiler warnings for this:
-Wcast-function-type for GCC and old Clang
and -Wcast-function-type in conjunction with
-Wno-cast-function-type-strict (without the latter,
Clang warns about conversions with different pointer
types, like int (*)(void*)->int (*)(struct Foo*);
the latter typically lead to UB (when used in a call),
but are actually common).

 libavcodec/cbs_h266_syntax_template.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/cbs_h266_syntax_template.c b/libavcodec/cbs_h266_syntax_template.c
index 26ee7a420b..e75f2f6971 100644
--- a/libavcodec/cbs_h266_syntax_template.c
+++ b/libavcodec/cbs_h266_syntax_template.c
@@ -3430,7 +3430,7 @@ static int FUNC(slice_header) (CodedBitstreamContext *ctx, RWContext *rw,
 static int FUNC(sei_decoded_picture_hash) (CodedBitstreamContext *ctx,
                                            RWContext *rw,
                                            H266RawSEIDecodedPictureHash *
-                                           current)
+                                           current, SEIMessageState *unused)
 {
     int err, c_idx, i;
 
-- 
2.40.1