diff options
Diffstat (limited to 'misc/sys')
| -rw-r--r-- | misc/sys/cdefs.h | 30 |
1 files changed, 18 insertions, 12 deletions
diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h index 6e9b8403d7..935a94b466 100644 --- a/misc/sys/cdefs.h +++ b/misc/sys/cdefs.h @@ -153,21 +153,27 @@ # define __errordecl(name, msg) extern void name (void) #endif -/* Support for flexible arrays. */ -#if __GNUC_PREREQ (2,97) -/* GCC 2.97 supports C99 flexible array members. */ +/* Support for flexible arrays. + Headers that should use flexible arrays only if they're "real" + (e.g. only if they won't affect sizeof()) should test + #if __glibc_c99_flexarr_available. */ +#if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L +# define __flexarr [] +# define __glibc_c99_flexarr_available 1 +#elif __GNUC_PREREQ (2,97) +/* GCC 2.97 supports C99 flexible array members as an extension, + even when in C89 mode or compiling C++ (any version). */ # define __flexarr [] +# define __glibc_c99_flexarr_available 1 +#elif defined __GNUC__ +/* Pre-2.97 GCC did not support C99 flexible arrays but did have + an equivalent extension with slightly different notation. */ +# define __flexarr [0] +# define __glibc_c99_flexarr_available 1 #else -# ifdef __GNUC__ -# define __flexarr [0] -# else -# if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L -# define __flexarr [] -# else /* Some other non-C99 compiler. Approximate with [1]. */ -# define __flexarr [1] -# endif -# endif +# define __flexarr [1] +# define __glibc_c99_flexarr_available 0 #endif |