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close(2)			 System	Calls			      close(2)

       close - close a file descriptor

       #include	<unistd.h>

       int close(int fildes);

       The  close()  function will deallocate the file descriptor indicated by
       fildes. To deallocate means to make the file descriptor	available  for
       return  by subsequent calls to open(2) or other functions that allocate
       file descriptors. All outstanding record	locks owned by the process  on
       the  file associated with the file descriptor will be removed (that is,

       If close() is interrupted by a signal that is to	be caught, it will re-
       turn -1 with errno set to EINTR and the state of	fildes is unspecified.

       When  all  file descriptors associated with a pipe or FIFO special file
       are closed, any data remaining in the pipe or FIFO will be discarded.

       When all	file descriptors associated with an open file description have
       been closed the open file description will be freed.

       If  the	link count of the file is 0, when all file descriptors associ-
       ated with the file are closed, the space	occupied by the	file  will  be
       freed and the file will no longer be accessible.

       If  a  STREAMS-based  (see  intro(2))  fildes is	closed and the calling
       process was previously registered to receive a SIGPOLL signal (see sig-
       nal(3C))	 for  events  associated  with	that  STREAM  (see I_SETSIG in
       streamio(7I)), the calling process will be unregistered for events  as-
       sociated	 with  the  STREAM.  The last  close() for a STREAM causes the
       STREAM associated with fildes  to  be  dismantled.  If  O_NONBLOCK  and
       O_NDELAY	 are  not  set	and  there have	been no	signals	posted for the
       STREAM, and if there is data on the module's write queue, close() waits
       up  to  15 seconds (for each module and driver) for any output to drain
       before dismantling the STREAM. The time delay can  be  changed  via  an
       I_SETCLTIME  ioctl(2)  request (see streamio(7I)). If the O_NONBLOCK or
       O_NDELAY	flag is	set, or	if there are any pending signals, close() does
       not wait	for output to drain, and dismantles the	STREAM immediately.

       If fildes is associated with one	end of a pipe, the last	close()	causes
       a hangup	to occur on the	other end of the pipe.	In  addition,  if  the
       other  end  of  the  pipe  has been named by fattach(3C), then the last
       close() forces the named	end to be detached  by	fdetach(3C).   If  the
       named  end has no open file descriptors associated with it and gets de-
       tached, the STREAM associated with that end is also dismantled.

       If fildes refers	to the master side of a	pseudo-terminal, a SIGHUP sig-
       nal  is	sent to	the process group, if any, for which the slave side of
       the pseudo-terminal is the  controlling	terminal.  It  is  unspecified
       whether	closing	 the  master  side  of the pseudo-terminal flushes all
       queued input and	output.

       If fildes refers	to the slave side of a STREAMS-based  pseudo-terminal,
       a zero-length message may be sent to the	master.

       If  fildes  refers  to  a  socket,  close() causes the socket to	be de-
       stroyed.	 If the	socket is connection-mode, and the SOCK_LINGER	option
       is  set	for  the  socket,  and the socket has untransmitted data, then
       close() will block for up to the	current	linger interval	until all data
       is transmitted.

       Upon  successful	 completion,  0	is returned. Otherwise,	-1 is returned
       and errno is set	to indicate the	error.

       The close() function will fail if:

       EBADF The fildes	argument is not	a valid	file descriptor.

       EINTR The close() function was interrupted by a signal.

	     The fildes	argument is on a remote	machine	and the	link  to  that
	     machine is	no longer active.

	     There  was	 no  free space	remaining on the device	containing the

       The close() function may	fail if:

       EIO   An	I/O error occurred while reading from or writing to  the  file

       An  application	that  used the stdio function fopen(3C)	to open	a file
       should use the corresponding fclose(3C) function	rather than close().

       See attributes(5) for descriptions of the following attributes:

       |      ATTRIBUTE	TYPE	     |	    ATTRIBUTE VALUE	   |
       |MT-Level		     |Async-Signal-Safe		   |

       intro(2),  creat(2),  dup(2),  exec(2),	fcntl(2),  ioctl(2),   open(2)
       pipe(2),	 fattach(3C),  fclose(3C), fdetach(3C),	fopen(3C), signal(3C),
       attributes(5), signal(3HEAD), streamio(7I)

SunOS 5.9			  4 Apr	1997			      close(2)


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