On Fri, Oct 21, 2016 at 11:50:02PM +0000, John Baldwin wrote: > Author: jhb > Date: Fri Oct 21 23:50:02 2016 > New Revision: 307756 > URL: https://svnweb.freebsd.org/changeset/base/307756 > > Log: > Define max_align_t for C11. > > libc++'s stddef.h includes an existing definition of max_align_t for > C++11, but it is only defined for C++, not for C. In addition, GCC and > clang both define an alternate version of max_align_t that uses a > union of multiple types rather than a plain long double as in libc++. > This adds a __max_align_t to <sys/_types.h> that matches the GCC and > clang definition that is mapped to max_align_t in <stddef.h>. > > PR: 210890 > Reviewed by: dim > MFC after: 1 month > Differential Revision: https://reviews.freebsd.org/D8194 > > Modified: > head/include/stddef.h > head/sys/sys/_types.h > > Modified: head/include/stddef.h > ============================================================================== > --- head/include/stddef.h Fri Oct 21 21:55:50 2016 (r307755) > +++ head/include/stddef.h Fri Oct 21 23:50:02 2016 (r307756) > @@ -62,6 +62,14 @@ typedef ___wchar_t wchar_t; > #endif > #endif > > +#if __STDC_VERSION__ >= 201112L || __cplusplus >= 201103L > +#ifndef __CLANG_MAX_ALIGN_T_DEFINED > +typedef __max_align_t max_align_t; > +#define __CLANG_MAX_ALIGN_T_DEFINED > +#define __GCC_MAX_ALIGN_T > +#endif > +#endif > + > #define offsetof(type, member) __offsetof(type, member) > > #endif /* _STDDEF_H_ */ > > Modified: head/sys/sys/_types.h > ============================================================================== > --- head/sys/sys/_types.h Fri Oct 21 21:55:50 2016 (r307755) > +++ head/sys/sys/_types.h Fri Oct 21 23:50:02 2016 (r307756) > @@ -100,6 +100,11 @@ typedef __uint_least32_t __char32_t; > #define _CHAR32_T_DECLARED > #endif > > +typedef struct {
Should this be union per the commit message? Ideally I'd add a void * as well since that will support systems like CHERI where pointers are the largest type. -- Brooks > + long long __max_align1 __aligned(_Alignof(long long)); > + long double __max_align2 __aligned(_Alignof(long double)); > +} __max_align_t; > + > typedef __uint32_t __dev_t; /* device number */ > > typedef __uint32_t __fixpt_t; /* fixed point number */ >
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