FCNTL(5)             INTERACTIVE UNIX System             FCNTL(5)



          NAME
               fcntl - file control options

          SYNOPSIS
               #include <fcntl.h>

          DESCRIPTION
               The fcntl(2) function provides for control over open files.
               This include file describes requests and arguments to fcntl
               and open(2).

               /* Flag values accessible to open(2) and fcntl(2) */
               /*  (The first three can only be set by open) */
               #define O_RDONLY 0
               #define O_WRONLY 1
               #define O_RDWR   2
               #define O_NDELAY 04      /* Non-blocking I/O */
               #define O_APPEND 010     /* append (writes guaranteed at the end) */
               #define O_SYNC   020     /* synchronous write option */

               /* Flag values accessible only to open(2) */
               #define O_CREAT  00400   /* open with file create (uses third open arg)*/
               #define O_TRUNC  01000   /* open with truncation */
               #define O_EXCL   02000   /* exclusive open */

               /* fcntl(2) requests */
               #define F_DUPFD  0       /* Duplicate fildes */
               #define F_GETFD  1       /* Get fildes flags */
               #define F_SETFD  2       /* Set fildes flags */
               #define F_GETFL  3       /* Get file flags */
               #define F_SETFL  4       /* Set file flags */
               #define F_GETLK  5       /* Get file lock */
               #define F_SETLK  6       /* Set file lock */
               #define F_SETLKW 7       /* Set file lock and wait */
               #define F_CHKFL  8       /* Check legality of file flag changes */

               /* file segment locking control structure */
               struct flock {
                     short l_type;
                     short l_whence;
                     long  l_start;
                     long  l_len;      /* if 0 then until EOF */
                     short l_sysid;    /* returned with F_GETLK*/
                     short l_pid;      /* returned with F_GETLK*/
               }

               /* file segment locking types */
               #define F_RDLCK 01   /* Read lock */
               #define F_WRLCK 02   /* Write lock */
               #define F_UNLCK 03   /* Remove locks */

          SEE ALSO
               fcntl(2), open(2).


          Rev.                                                       Page 1