fcntl(5)                                                           fcntl(5)




 NAME    [Toc]    [Back]
      fcntl - file control options

 SYNOPSIS    [Toc]    [Back]
      #include <sys/types.h>

      #include <fcntl.h>

 DESCRIPTION    [Toc]    [Back]
      The fcntl() function provides for control over open files.  The
      <fcntl.h> include file describes requests and arguments to fcntl() and
      open().  See fcntl(2) and open(2).

      The access modes set by open() and accessed by fcntl() are:

           O_RDONLY    [Toc]    [Back]
           O_WRONLY
           O_RDWR

      The mask for file access modes is:

           O_ACCMODE    [Toc]    [Back]

      The file status flags set by open() or fcntl() and accessed by fcntl()
      are:

           O_NDELAY                 Nonblocking I/O.
           O_NONBLOCK               POSIX-style nonblocking I/O.
           O_APPEND                 Append (writes guaranteed at the end).
           O_DSYNC                  Write through cache for data.
           O_SYNC                   Write through cache for data and
                                    attributes.
           O_RSYNC|O_DSYNC          Write through cache for data on reads
                                    and writes.
           O_RSYNC|O_SYNC           Write through cache for data and
                                    attributes on reads and writes.
           O_LARGEFILE              When the filesystem is mounted as large
                                    files enabled, the O_LARGEFILE option
                                    allows the file to grow over 2 GB.

      The flag O_SYNCIO is a synonym for O_SYNC and is defined for backward
      compatibility in <fcntl.h>.

      The flag values accessible only to open() are:

           O_CREAT                  Open with file create (uses third open
                                    arg).
           O_TRUNC                  Open with truncation.
           O_EXCL                   Exclusive open.
           O_NOCTTY                 Do not assign a controlling terminal.




 Hewlett-Packard Company            - 1 -   HP-UX 11i Version 2: August 2003






 fcntl(5)                                                           fcntl(5)




      The requests for fcntl() are:

           F_DUPFD                  Duplicate file descriptor.
           F_GETFD                  Get file descriptor flags.
           F_SETFD                  Set file descriptor flags.
           F_GETFL                  Get file flags.
           F_SETFL                  Set file flags.
           F_GETLK                  Get blocking file lock.
           F_SETLK                  Set or clear file locks and fail on
                                    busy.
           F_SETLKW                 Set or clear file locks and wait on
                                    busy.

      The file descriptor flag for F_GETFD, F_SETFD is:

           FD_CLOEXEC    [Toc]    [Back]

      The file segment locking control structure struct flock, includes the
      following members:

           short l_type;      /* F_RDLCK, F_WRLCK or F_UNLCK */
           short l_whence;    /* Flag - see lseek(2) */
           off_t l_start;     /* Relative offset in bytes */
           off_t l_len;       /* Size; if 0 then until EOF */
           pid_t l_pid;       /* By F_GETLK - process holding lock */

      The file segment locking types are:
           F_RDLCK            Read lock.
           F_WRLCK            Write lock.
           F_UNLCK            Remove locks.

 SEE ALSO    [Toc]    [Back]
      fcntl(2), open(2).

 STANDARDS CONFORMANCE    [Toc]    [Back]
      <fcntl.h>: AES, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1


 Hewlett-Packard Company            - 2 -   HP-UX 11i Version 2: August 2003