FCNTL(5-SysV)       RISC/os Reference Manual        FCNTL(5-SysV)



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 */





                         Printed 1/15/91                   Page 1

FCNTL(5-SysV)       RISC/os Reference Manual        FCNTL(5-SysV)



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





















































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