From 6eff829d788b36939325557066f58aafd6a05321 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Thu, 12 Apr 2018 10:26:22 +0200 Subject: [PATCH] utils: fix build error with g++ g++ does not support __builtin_choose_expr, so we can't support byte swapping as constant expression there. Reported-by: Cleynhens Stijn Signed-off-by: Felix Fietkau --- utils.h | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/utils.h b/utils.h index b64b400..019d817 100644 --- a/utils.h +++ b/utils.h @@ -127,9 +127,18 @@ int clock_gettime(int type, struct timespec *tv); #define __eval_once(func, x) \ ({ __typeof__(x) __x = x; func(__x); }) +#ifdef __cplusplus +/* + * g++ does not support __builtin_choose_expr, so always use __eval_once. + * Unfortunately this means that the byte order functions can't be used + * as a constant expression anymore + */ +#define __eval_safe(func, x) __eval_once(func, x) +#else #define __eval_safe(func, x) \ __builtin_choose_expr(__is_constant(x), \ func(x), __eval_once(func, x)) +#endif #if __BYTE_ORDER == __LITTLE_ENDIAN -- 2.25.1