39#if XF_ATTRIBUTE_IS_ENABLE
48# define __weak __attribute__((weak))
60# define __used __attribute__((used))
67# if !defined(__aligned)
73# define __aligned(x) __attribute__((aligned(x)))
77# warning "__aligned has no effect !"
81# if !defined(__section)
87# define __section(x) __attribute__((section(x)))
100# define likely(x) __builtin_expect(!!(x), 1)
103# define likely(x) (x)
107# if !defined(unlikely)
113# define unlikely(x) __builtin_expect(!!(x), 0)
116# define unlikely(x) (x)
120# if !defined(__packed)
124# define __packed __attribute__((packed))
128# warning "__packed has no effect !"
预定义. xf_attr.h 等头文件通过包含本文件减少对其余外部文件的直接依赖. 如: xfconfig.h.