BUG: use _Alignof rather than offsetof() on most compilers
#23031
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…#23016) WG14 N2350 made very clear that it is an UB having type definitions within "offsetof" [1]. This patch enhances the implementation of macro _ALIGN to use builtin "_Alignof" to avoid undefined behavior on when using std=c11 or newer clang 16+ has started to flag this [2] Fixes build when using -std >= gnu11 and using clang16+ Older compilers gcc < 4.9 or clang < 8 has buggy _Alignof even though it may support C11, exclude those compilers too [1] https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm [2] https://reviews.llvm.org/D133574 Signed-off-by: Khem Raj <raj.khem@gmail.com> * Apply suggestions from code review Signed-off-by: Khem Raj <raj.khem@gmail.com> Co-authored-by: Sebastian Berg <sebastian@sipsolutions.net>
charris
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_Alignof rather than offsetof() on most compilers_Alignof rather than offsetof() on most compilers
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Backport of #23016.
WG14 N2350 made very clear that it is an UB having type definitions within "offsetof" [1]. This patch enhances the implementation of macro _ALIGN to use builtin "_Alignof" to avoid undefined behavior on when using std=c11 or newer
clang 16+ has started to flag this [2]
Fixes build when using -std >= gnu11 and using clang16+
Older compilers gcc < 4.9 or clang < 8 has buggy _Alignof even though it may support C11, exclude those compilers too
[1] https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm [2] https://reviews.llvm.org/D133574
Signed-off-by: Khem Raj raj.khem@gmail.com
Signed-off-by: Khem Raj raj.khem@gmail.com
Co-authored-by: Sebastian Berg sebastian@sipsolutions.net