On 9/26/2021 6:46 AM, Andreas Rheinhardt wrote:
avutil_version() currently performs several checks before
just returning the version. There is a static int that aims
to ensure that these tests are run only once. The reason is that
there used to be a slightly expensive check, but it has been removed
in 92e3a6fdac73f7e1d69d69717219a7538877d7a0. Today running only
once is unnecessary and can be counterproductive: GCC 10 optimizes
all the actual checks away, but the checks_done variable and the code
setting it has been kept. Given that this check is inherently racy
(it uses non-atomic variables), it is best to just remove it.
Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@outlook.com>
---
A part of me just wants to nuke all those checks.
(We have zero callers of avutil_version() in the codebase and
I don't see a reason why external users should call it more often,
so all those checks probably don't fulfill their aim.)
We could replace them with C11's _Static_assert (Making sure that for
C99 compilers like msvc it just becomes av_assert0). That way they will
trigger at compilation time instead, which is more in line to what they
were added for.
libavutil/utils.c | 5 -----
1 file changed, 5 deletions(-)
diff --git a/libavutil/utils.c b/libavutil/utils.c
index c1cd452eee..ea9b5097b8 100644
--- a/libavutil/utils.c
+++ b/libavutil/utils.c
@@ -37,10 +37,6 @@ const char *av_version_info(void)
unsigned avutil_version(void)
{
- static int checks_done;
- if (checks_done)
- return LIBAVUTIL_VERSION_INT;
-
av_assert0(AV_SAMPLE_FMT_DBLP == 9);
av_assert0(AVMEDIA_TYPE_ATTACHMENT == 4);
av_assert0(AV_PICTURE_TYPE_BI == 7);
@@ -58,7 +54,6 @@ unsigned avutil_version(void)
av_log(NULL, AV_LOG_ERROR, "Libavutil has been linked to a broken
llrint()\n");
}
- checks_done = 1;
return LIBAVUTIL_VERSION_INT;
}
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