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



NAME
     fcntl - file control options

SYNOPSIS
     #include <sys/types.h>
     #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 */
     #define O_NOCTTY   0x20     /* don't acquire controlling terminal */
     #define O_NONBLOCK O_NDELAY /* non-blocking I/O (POSIX)*/
     #define O_ACCMODE  0x3      /* mask for access modes */

     /* 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 */

     /* flags for F_SETFL and F_GETFL */
     #define FD_CLOEXEC 1        /* Close on exec */

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



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



     /* 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).
















































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