include/fcntl.h

   1 /* The <fcntl.h> header is needed by the open() and fcntl() system calls,
   2  * which  have a variety of parameters and flags.  They are described here.
   3  * The formats of the calls to each of these are:
   4  *
   5  *      open(path, oflag [,mode])       open a file
   6  *      fcntl(fd, cmd [,arg])           get or set file attributes
   7  *
   8  */
   9
  10 #ifndef _FCNTL_H
  11 #define _FCNTL_H
  12
  13 #ifndef _TYPES_H
  14 #include <sys/types.h>
  15 #endif
  16
  17 /* These values are used for cmd in fcntl().  POSIX Table 6-1.  */
  18 #define F_DUPFD            0    /* duplicate file descriptor */
  19 #define F_GETFD            1    /* get file descriptor flags */
  20 #define F_SETFD            2    /* set file descriptor flags */
  21 #define F_GETFL            3    /* get file status flags */
  22 #define F_SETFL            4    /* set file status flags */
  23 #define F_GETLK            5    /* get record locking information */
  24 #define F_SETLK            6    /* set record locking information */
  25 #define F_SETLKW           7    /* set record locking info; wait if blocked */
  26 #define F_FREESP           8    /* free a section of a regular file */
  27
  28 /* File descriptor flags used for fcntl().  POSIX Table 6-2. */
  29 #define FD_CLOEXEC         1    /* close on exec flag for third arg of fcntl */
  30
  31 /* L_type values for record locking with fcntl().  POSIX Table 6-3. */
  32 #define F_RDLCK            1    /* shared or read lock */
  33 #define F_WRLCK            2    /* exclusive or write lock */
  34 #define F_UNLCK            3    /* unlock */
  35
  36 /* Oflag values for open().  POSIX Table 6-4. */
  37 #define O_CREAT        00100    /* creat file if it doesn't exist */
  38 #define O_EXCL         00200    /* exclusive use flag */
  39 #define O_NOCTTY       00400    /* do not assign a controlling terminal */
  40 #define O_TRUNC        01000    /* truncate flag */
  41
  42 /* File status flags for open() and fcntl().  POSIX Table 6-5. */
  43 #define O_APPEND       02000    /* set append mode */
  44 #define O_NONBLOCK     04000    /* no delay */
  45 #define O_REOPEN      010000    /* automatically re-open device after driver
  46                                  * restart
  47                                  */
  48
  49 /* File access modes for open() and fcntl().  POSIX Table 6-6. */
  50 #define O_RDONLY           0    /* open(name, O_RDONLY) opens read only */
  51 #define O_WRONLY           1    /* open(name, O_WRONLY) opens write only */
  52 #define O_RDWR             2    /* open(name, O_RDWR) opens read/write */
  53
  54 /* Mask for use with file access modes.  POSIX Table 6-7. */
  55 #define O_ACCMODE         03    /* mask for file access modes */
  56
  57 /* Struct used for locking.  POSIX Table 6-8. */
  58 struct flock {
  59   short l_type;                 /* type: F_RDLCK, F_WRLCK, or F_UNLCK */
  60   short l_whence;               /* flag for starting offset */
  61   off_t l_start;                /* relative offset in bytes */
  62   off_t l_len;                  /* size; if 0, then until EOF */
  63   pid_t l_pid;                  /* process id of the locks' owner */
  64 };
  65
  66 /* Function Prototypes. */
  67 _PROTOTYPE( int creat, (const char *_path, _mnx_Mode_t _mode)           );
  68 _PROTOTYPE( int fcntl, (int _filedes, int _cmd, ...)                    );
  69 _PROTOTYPE( int open,  (const char *_path, int _oflag, ...)             );
  70
  71 /* For locking files. */
  72 #define LOCK_SH         F_RDLCK         /* Shared lock */
  73 #define LOCK_EX         F_WRLCK         /* Exclusive lock */
  74 #define LOCK_NB         0x0080          /* Do not block when locking */
  75 #define LOCK_UN         F_UNLCK         /* Unlock */
  76
  77 _PROTOTYPE(  int flock, (int fd, int mode)                              );
  78
  79 #endif /* _FCNTL_H */