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close(2)
NAME
  close -  Closes the file associated with a file descriptor

SYNOPSIS
  #include <unistd.h>

  int close (
	  int filedes );

PARAMETERS
  filedes   Specifies a valid open file descriptor.

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  close():  XPG4, XPG4-UNIX

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.


DESCRIPTION
  The close() function closes the file associated with the filedes parameter.

  All regions of a file specified by the filedes parameter that this process
  has previously locked with the lockf() function are unlocked. This occurs
  even if the process still has the file open by another file descriptor.

  When all file descriptors associated with a pipe or FIFO special file have
  been closed, any data remaining in the pipe or FIFO is discarded.  When all
  file descriptors associated with an open file descriptor are closed, the
  open file descriptor is freed.  If the link count of the file is 0 (zero)
  when all file descriptors associated with the file have been closed, the
  space occupied by the file is freed and the file is no longer accessible.

  When the close() function needs to block, only the calling thread is
  suspended rather than all threads in the calling process.

  The last close() for a stream causes the stream associated with fildes to
  be dismantled. Dismantling includes popping any modules on the stream and
  closing the driver.  If O_NDELAY and O_NONBLOCK are clear and there are no
  signals posted for the stream, close() waits up to 15 seconds for each
  module to drain and up to 15 seconds for each driver to drain.  If the
  O_NDELAY or the O_NONBLOCK flag is set or if there are any pending signals,
  close() does not wait for output to drain, and dismantles the stream
  immediately.	If a STREAMS file is closed, and the calling process had
  previously registered to receive a SIGPOLL signal [see signal()] for events
  associated with that file [see I_SETSIG in streamio(7)], the calling
  process is unregistered for events associated with the file.

RETURN VALUES
  Upon successful completion, a value of 0 (zero) is returned. Otherwise, a
  value of -1 is returned and errno is set to indicate the error.

ERRORS
  If the close() function fails, errno may be set to one of the following
  values:

  [EBADF]   The filedes parameter is not a valid open file descriptor.

  [EINTR]   The close() function was interrupted by a signal which was
	    caught.

  [ENETUNREACH]
	    fildes is on a remote machine and the link to that machine is no
	    longer active.

  [Digital] A close() function on an NFS file system waits for all
  outstanding I/O to complete.	If any operation completes with an error, the
  error will be returned by close().  The possible errors depend on the NFS
  server implementation, but the most likely errors are:

  [EDQUOT]  The write has failed because the user's disk block quota is
	    exhausted.

  [EFBIG]   Attempted to write a file that exceeds the maximum file size.

  [EIO]	    A read or write physical I/O error.

  [ENOSPC]  Attempted to write on a full file system.

RELATED INFORMATION
  Functions: exec(2), fcntl(2), lockf(3), open(2), pipe(2), socket(2),
  streamio(7)

  Standards: standards(5)