linux内核中的fcntl.h文件操作中的打开文件模式的宏定义

#ifndef _ALPHA_FCNTL_H
#define _ALPHA_FCNTL_H
/* open/fcntl - O_SYNC is only implemented on blocks devices and on files
located on an ext2 file system */
#define O_ACCMODE     0003   //
#define O_RDONLY        00   //只读打开
#define O_WRONLY        01   //只写打开
#define O_RDWR          02   //读写打开
#define O_CREAT      01000  /* not fcntl *///文件不存在则创建
#define O_TRUNC      02000  /* not fcntl */若文件存在并且写方式打开成功，则将文件截短为0
#define O_EXCL       04000  //测试文件是否存在，不存在则创建
#define O_NOCTTY    010000  //如果pathname指向一个终端设备，则不会把此设备终端分配给作为当前进程的控制终端
#define O_NONBLOCK   00004   //如果指定文件为命名管道、快设备、或者字符设备，则将此设备设为阻塞
#define O_APPEND     00010   //每次写文件都把数据加到文件结尾
#define O_NDELAY    O_NONBLOCK  //对文件使用非阻塞方式
#define O_SYNC      040000
#define FASYNC      020000  /* fcntl, for BSD compatibility */
#define O_DIRECTORY 0100000 /* must be a directory */
#define O_NOFOLLOW  0200000 /* don't follow links */
#define O_LARGEFILE 0400000 /* will be set by the kernel on every open */
#define O_DIRECT    02000000 /* direct disk access - should check with OSF/1 */
#define O_NOATIME   04000000
#define F_DUPFD     0   /* dup */
#define F_GETFD     1   /* get close_on_exec */
#define F_SETFD     2   /* set/clear close_on_exec */
#define F_GETFL     3   /* get file->f_flags */
#define F_SETFL     4       /* set file->f_flags */
#define F_GETLK     7
#define F_SETLK     8
#define F_SETLKW    9
#define F_SETOWN    5   /*  for sockets. */
#define F_GETOWN    6   /*  for sockets. */
#define F_SETSIG    10  /*  for sockets. */
#define F_GETSIG    11  /*  for sockets. */
/* for F_[GET|SET]FL */
#define FD_CLOEXEC  1   /* actually anything with low bit set goes */
/* for posix fcntl() and lockf() */
#define F_RDLCK     1
#define F_WRLCK     2
#define F_UNLCK     8
/* for old implementation of bsd flock () */
#define F_EXLCK     16  /* or 3 */
#define F_SHLCK     32  /* or 4 */
#define F_INPROGRESS    64
/* operations for bsd flock(), also used by the kernel implementation */
#define LOCK_SH     1   /* shared lock */
#define LOCK_EX     2   /* exclusive lock */
#define LOCK_NB     4   /* or'd with one of the above to prevent
blocking */
#define LOCK_UN     8   /* remove lock */
#define LOCK_MAND      32      /* This is a mandatory flock */
#define LOCK_READ      64      /* ... Which allows concurrent read operations */
#define LOCK_WRITE     128     /* ... Which allows concurrent write operations */
#define LOCK_RW        192     /* ... Which allows concurrent read & write ops */

struct flock {
short l_type;
short l_whence;
__kernel_off_t l_start;
__kernel_off_t l_len;
__kernel_pid_t l_pid;
};
#define F_LINUX_SPECIFIC_BASE  1024
#endif