| Message ID | GV1P250MB073720AB24FC4F56F3EFAC2D8F312@GV1P250MB0737.EURP250.PROD.OUTLOOK.COM |
|---|---|
| State | Accepted |
| Commit | 0d43adcbef9a061c95db60eb351937c27e2a0609 |
| Headers | show |
| Series | [FFmpeg-devel,v3] configure: Explicitly check for static_assert, _Static_assert | expand |
| Context | Check | Description |
|---|---|---|
| yinshiyou/make_loongarch64 | success | Make finished |
| yinshiyou/make_fate_loongarch64 | success | Make fate finished |
| andriy/make_x86 | success | Make finished |
| andriy/make_fate_x86 | success | Make fate finished |
Andreas Rheinhardt: > C11 provides static assertions via _Static_assert and > provides static_assert as a convenience define for this > in assert.h. Our codebase uses the latter, as _Static_assert > has actually already been deprecated in C23. > > Not all toolchains that declare support for C11 actually > support it; e.g. MSVC 19.27 does not support _Static_assert, > but somehow supports static_assert. MSVC 19.27 admits to be > a "preview implementation of the ISO C11 standard", > so this is not surprising (MSVC 19.28 does not come with > this caveat). > > Furthermore some FATE boxes [1] use old GCC toolchains (with > only experimental support for C11) where _Static_assert is > supported, but assert.h does not provide the fallback define. > They are broken since the first usage of static_assert. > > This commit therefore checks whether static_assert and > _Static_assert work with assert.h included; if not, > configure errors out. > > This intentionally drops support for MSVC 19.27. Users like > the old FATE boxes above can still add -Dstatic_assert=_Static_assert > to cflags as a workaround if desired. > > [1]: https://fate.ffmpeg.org/report.cgi?time=20240321123620&slot=sh4-debian-qemu-gcc-4.7 > > Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com> > --- > configure | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/configure b/configure > index 343edb38ab..fc366549bc 100755 > --- a/configure > +++ b/configure > @@ -5589,6 +5589,19 @@ check_cxxflags_cc -std=$stdcxx ctype.h "__cplusplus >= 201103L" || > check_cflags_cc -std=$stdc ctype.h "__STDC_VERSION__ >= 201112L" || > { check_cflags_cc -std=c11 ctype.h "__STDC_VERSION__ >= 201112L" && stdc="c11" || die "Compiler lacks C11 support"; } > > +test_cc <<EOF || die "Compiler lacks support for C11 static assertions" > +#include <assert.h> > +#include <stddef.h> > +struct Foo { > + int a; > + void *ptr; > +} obj; > +static_assert(offsetof(struct Foo, a) == 0, > + "First element of struct does not have offset 0"); > +_Static_assert(offsetof(struct Foo, ptr) >= offsetof(struct Foo, a) + sizeof(obj.a), > + "elements not properly ordered in struct"); > +EOF > + > check_cppflags -D_FILE_OFFSET_BITS=64 > check_cppflags -D_LARGEFILE_SOURCE > Will apply this patch tomorrow unless there are objections. - Andreas
diff --git a/configure b/configure index 343edb38ab..fc366549bc 100755 --- a/configure +++ b/configure @@ -5589,6 +5589,19 @@ check_cxxflags_cc -std=$stdcxx ctype.h "__cplusplus >= 201103L" || check_cflags_cc -std=$stdc ctype.h "__STDC_VERSION__ >= 201112L" || { check_cflags_cc -std=c11 ctype.h "__STDC_VERSION__ >= 201112L" && stdc="c11" || die "Compiler lacks C11 support"; } +test_cc <<EOF || die "Compiler lacks support for C11 static assertions" +#include <assert.h> +#include <stddef.h> +struct Foo { + int a; + void *ptr; +} obj; +static_assert(offsetof(struct Foo, a) == 0, + "First element of struct does not have offset 0"); +_Static_assert(offsetof(struct Foo, ptr) >= offsetof(struct Foo, a) + sizeof(obj.a), + "elements not properly ordered in struct"); +EOF + check_cppflags -D_FILE_OFFSET_BITS=64 check_cppflags -D_LARGEFILE_SOURCE
C11 provides static assertions via _Static_assert and provides static_assert as a convenience define for this in assert.h. Our codebase uses the latter, as _Static_assert has actually already been deprecated in C23. Not all toolchains that declare support for C11 actually support it; e.g. MSVC 19.27 does not support _Static_assert, but somehow supports static_assert. MSVC 19.27 admits to be a "preview implementation of the ISO C11 standard", so this is not surprising (MSVC 19.28 does not come with this caveat). Furthermore some FATE boxes [1] use old GCC toolchains (with only experimental support for C11) where _Static_assert is supported, but assert.h does not provide the fallback define. They are broken since the first usage of static_assert. This commit therefore checks whether static_assert and _Static_assert work with assert.h included; if not, configure errors out. This intentionally drops support for MSVC 19.27. Users like the old FATE boxes above can still add -Dstatic_assert=_Static_assert to cflags as a workaround if desired. [1]: https://fate.ffmpeg.org/report.cgi?time=20240321123620&slot=sh4-debian-qemu-gcc-4.7 Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com> --- configure | 13 +++++++++++++ 1 file changed, 13 insertions(+)