Content #
判断x是否在编译时就可以被确定为常量。如果x为常量，该函数返回1，否则返回0。
#define __swab16(x) \
(__builtin_constant_p((__u16)(x)) ? \
___constant_swab16(x) : \
__fswab16(x))
From #
奔跑吧Linux内核——入门篇
__builtin_constant_p(x)
January 28, 2024
__builtin_constant_p(x)
January 28, 2024