fcntl(5)                         UNIX System V                         fcntl(5)


NAME
      fcntl - file control options

SYNOPSIS
      #include <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):
              FDUPFD        Duplicate file descriptor
              FGETFD        Get file descriptor flags
              FSETFD        Set file descriptor flags
              FGETFL        Get file status flags
              FSETFL        Set file status flags
              FGETLK        Get record locking information
              FSETLK        Set record locking information
              FSETLKW       Set record locking information;
                             wait if blocked
         File descriptor flags used for fcntl:
              FDCLOEXEC     Close the file descriptor upon
                             execution of an exec function [see exec(2)]
         Values for ltype used for record locking with fcntl
         (the following values are unique):
              FRDLCK        Shared or read lock
              FUNLCK        Unlock
              FWRLCK        Exclusive or write lock
         The following three sets of values are bitwise distinct:
         Values for oflag used by open:
              OCREAT        Create file if it does not exist
              OEXCL         Exclusive use flag
              ONOCTTY       Do not assign controlling tty
              OTRUNC        Truncate flag
         File status flags used for open and fcntl:
              OAPPEND       Set append mode
              ONDELAY       Non-blocking mode
              ONONBLOCK     Non-blocking mode (POSIX)
              OSYNC         Synchronous writes
         Mask for use with file access modes:
              OACCMODE      Mask for file access modes
         File access modes used for open and fcntl:
              ORDONLY       Open for reading only
              ORDWR         Open for reading and writing
              OWRONLY       Open for writing only

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

         short   ltype;     /* Type of lock */
         short   lwhence;   /* Flag for starting offset */
         offt   lstart;    /* Relative offset in bytes */


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fcntl(5)                         UNIX System V                         fcntl(5)


         offt   llen;      /* Size; if 0 then until EOF */
         long    lsysid;    /* Returned with FGETLK */
         pidt   lpid;      /* Returned with FGETLK */

SEE ALSO
      creat(2), exec(2), fcntl(2), open(2)
















































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