compiler.h

来自「linux得一些常用命令,以及linux环境下的c编程」· C头文件 代码 · 共 17 行

#ifndef __LINUX_COMPILER_H
#define __LINUX_COMPILER_H

/* Somewhere in the middle of the GCC 2.96 development cycle, we implemented
   a mechanism by which the user can annotate likely branch directions and
   expect the blocks to be reordered appropriately.  Define __builtin_expect
   to nothing for earlier compilers.  */

#if __GNUC__ == 2 && __GNUC_MINOR__ < 96
#define __builtin_expect(x, expected_value) (x)
#endif

#define likely(x)	__builtin_expect((x),1)
#define unlikely(x)	__builtin_expect((x),0)

#endif /* __LINUX_COMPILER_H */