git: 7148e1593b68 - stable/13 - <sys/cdefs.h>: Decay expression passed to fallback version of __generic()
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Date: Wed, 28 Jun 2023 01:33:11 UTC
The branch stable/13 has been updated by jhb: URL: https://cgit.FreeBSD.org/src/commit/?id=7148e1593b6866bfaf5d640d099af1931d053459 commit 7148e1593b6866bfaf5d640d099af1931d053459 Author: John Baldwin <jhb@FreeBSD.org> AuthorDate: 2023-01-27 00:28:22 +0000 Commit: John Baldwin <jhb@FreeBSD.org> CommitDate: 2023-06-28 01:32:47 +0000 <sys/cdefs.h>: Decay expression passed to fallback version of __generic() This ensures that __generic() more closely matches _Generic() when using the fallback version when _Generic() is not available (such as GCC). Co-authored by: jrtc27 Reviewed by: jrtc27 Differential Revision: https://reviews.freebsd.org/D38215 (cherry picked from commit 9d2f9798175586bdcd3423443804fbbc0cffb8d2) --- sys/sys/cdefs.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/sys/sys/cdefs.h b/sys/sys/cdefs.h index 3d45271d3e31..28e464122e58 100644 --- a/sys/sys/cdefs.h +++ b/sys/sys/cdefs.h @@ -313,6 +313,9 @@ * __generic(). Unlike _Generic(), this macro can only distinguish * between a single type, so it requires nested invocations to * distinguish multiple cases. + * + * Note that the comma operator is used to force expr to decay in + * order to match _Generic(). */ #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) || \ @@ -322,7 +325,7 @@ #elif __GNUC_PREREQ__(3, 1) && !defined(__cplusplus) #define __generic(expr, t, yes, no) \ __builtin_choose_expr( \ - __builtin_types_compatible_p(__typeof(expr), t), yes, no) + __builtin_types_compatible_p(__typeof((0, (expr))), t), yes, no) #endif /*