The status information word st_mode has the following bits:

     #define S_IFMT   0170000  /* type of file mask */
     #define S_IFIFO  0010000  /* named pipe (fifo) */
     #define S_IFCHR  0020000  /* character special */
     #define S_IFDIR  0040000  /* directory */
     #define S_IFBLK  0060000  /* block special */
     #define S_IFREG  0100000  /* regular */
     #define S_IFLNK  0120000  /* symbolic link */
     #define S_IFSOCK 0140000  /* socket */
     #define S_IFWHT  0160000  /* whiteout */
     #define S_ISUID  0004000  /* set user id on execution */
     #define S_ISGID  0002000  /* set group id on execution */
     #define S_ISVTX  0001000  /* save swapped text even after use */
     #define S_IRWXU  0000700  /* RWX mask for owner */
     #define S_IRUSR  0000400  /* read permission, owner */
     #define S_IWUSR  0000200  /* write permission, owner */
     #define S_IXUSR  0000100  /* execute/search permission, owner */
     #define S_IRWXG  0000070  /* RWX mask for group */
     #define S_IRGRP  0000040  /* read permission, group */
     #define S_IWGRP  0000020  /* write permission, group */
     #define S_IXGRP  0000010  /* execute/search permission, group */
     #define S_IRWXO  0000007  /* RWX mask for other */
     #define S_IROTH  0000004  /* read permission, other */
     #define S_IWOTH  0000002  /* write permission, other */
     #define S_IXOTH  0000001  /* execute/search permission, other */