fcntl(5)                                                    fcntl(5)


       NAME
             fcntl - file control options

       SYNOPSIS
             #include <sys/fcntl.h>

       DESCRIPTION
             The fcntl.h header defines the following requests and
             arguments for use by the functions fcntl [see fcntl(2)] and
             open [see open(2)].

             Values for cmd used by fcntl (the following values are
             unique):
                      F_DUPFD      Duplicate file descriptor
                      F_GETFD      Get file descriptor flags
                      F_SETFD      Set file descriptor flags
                      F_GETFL      Get file status flags
                      F_SETFL      Set file status flags
                      F_GETLK      Get record locking information
                      F_SETLK      Set record locking information
                      F_SETLKW     Set record locking
                                   information;wait if blocked

             File descriptor flags used for fcntl:
                      FD_CLOEXEC   Close the file descriptor upon
                                   execution of an exec function
                                   [see exec(2)]

             Values for l_type used for record locking with fcntl (the
             following values are unique):
                      F_RDLCK      Shared or read lock
                      F_UNLCK      Unlock
                      F_WRLCK      Exclusive or write lock

             The following three sets of values are bitwise distinct:
             Values for oflag used by open:
                     O_CREAT      Create file if it does not exist
                     O_EXCL       Exclusive use flag
                     O_NOCTTY     Do not assign controlling tty
                     O_TRUNC      Truncate flag

             File status flags used for open and fcntl:






                           Copyright 1994 Novell, Inc.               Page 1

      fcntl(5)                                                    fcntl(5)


                     O_APPEND     Set append mode
                     O_NDELAY     Non-blocking mode
                     O_NONBLOCK   Non-blocking mode (POSIX)
                     O_SYNC       Synchronous writes

            Mask for use with file access modes:
                     O_ACCMODE    Mask for file access modes

            File access modes used for open and fcntl:
                     O_RDONLY     Open for reading only
                     O_RDWR       Open for reading and writing
                     O_WRONLY     Open for writing only

            The structure flock describes a file lock.  It includes the
            following members:

               short   l_type;     /* Type of lock */
               short   l_whence;   /* Flag for starting offset */
               off_t   l_start;    /* Relative offset in bytes */
               off_t   l_len;      /* Size; if 0 then until EOF */
               long    l_sysid;    /* Returned with F_GETLK */
               pid_t   l_pid;      /* Returned with F_GETLK */
               long    l_pad       /* reserve area */

            See <unistd.h> for definition of values SEEK_CUR, SEEK_END,
            and SEEK_SET which are used for the l_whence member of the
            flock structure.

      REFERENCES
            creat(2), exec(2), fcntl(2), open(2)


















                          Copyright 1994 Novell, Inc.               Page 2