sys/stat.h
定义了一些"系统"的常量表示文件的读写执行属性
#ifndef _SYS_STAT_H
#define _SYS_STAT_H
#include <features.h>
#include <sys/types.h>
#include __SYSINC__(stat.h)
int stat __P((__const char * __path, struct stat * __statbuf));
int lstat __P((__const char * __path, struct stat * __statbuf));
int fstat __P((int __fd, struct stat * __statbuf));
/* hysterical raisins */
#define S_IREAD S_IRUSR /* read permission, owner */
#define S_IWRITE S_IWUSR /* write permission, owner */
#define S_IEXEC S_IXUSR /* execute/search permission, owner */
#endif