close(2)                                                              close(2)


NAME
     close - close a file descriptor

SYNOPSIS
     #include <unistd.h>
     int close(int fildes);

DESCRIPTION
     fildes is a file descriptor obtained from a creat, open, dup, fcntl,
     pipe, or iocntl system call.  close closes the file descriptor indicated
     by fildes.  All outstanding record locks owned by the process (on the
     file indicated by fildes) are removed.

     If the link count of the file is 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.

     If a STREAMS-based [see intro(2)] fildes is closed, and the calling
     process had previously registered to receive a SIGPOLL signal [see
     signal(5)] for events associated with that stream [see I_SETSIG in
     streamio(7)], the calling process will be unregistered for events
     associated with the stream.  The last close for a stream causes the
     stream associated with fildes to be dismantled.  If O_NDELAY and
     O_NONBLOCK are clear and there have been no signals posted for the
     stream, and if there are 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 request [see streamio(7)].  If O_NDELAY or O_NONBLOCK 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 [see fattach(3C)], the last close forces
     the named end to be detached [see fdetach(3C)].  If the named end has no
     open processes associated with it and becomes detached, the stream
     associated with that end is also dismantled.

     When closing all (or most) of a process's open file descriptors, it is
     best not to close all descriptors up to the system maximum, as this value
     can be large.  See getdtablehi(3C).

     The named file is closed unless one or more of the following are true:

     EBADF          fildes is not a valid open file descriptor.

     EINTR          A signal was caught during the close system call.

     ETIMEDOUT      The object of the close is located on a remote system
                    which is not available [see intro(2)].


     If the named file is a remote object accessed via NFS, close may return
     errors from a buffered write call.

SEE ALSO
     creat(2), dup(2), exec(2), fattach(3C), fcntl(2), fdetach(3C),
     getdtablehi(3C), intro(2), open(2), pipe(2), signal(2), signal(5),
     streamio(7)

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


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