CLOSE(2)						      BSD System Calls Manual							  CLOSE(2)

NAME

     close -- delete a descriptor

SYNOPSIS

     #include <unistd.h>

     int
     close(int fildes);

DESCRIPTION

     The close() call deletes a descriptor from the per-process object reference table.  If this is the last reference to the underlying object,
     the object will be deactivated.  For example, on the last close of a file the current seek pointer associated with the file is lost; on the
     last close of a socket(2) associated naming information and queued data are discarded; on the last close of a file holding an advisory lock
     the lock is released (see further flock(2)).

     When a process exits, all associated file descriptors are freed, but since there is a limit on active descriptors per processes, the close()
     function call is useful when a large quantity of file descriptors are being handled.

     When a process forks (see fork(2)), all descriptors for the new child process reference the same objects as they did in the parent before the
     fork.  If a new process is then to be run using execve(2), the process would normally inherit these descriptors.  Most of the descriptors can
     be rearranged with dup2(2) or deleted with close() before the execve is attempted, but if some of these descriptors will still be needed if
     the execve fails, it is necessary to arrange for them to be closed if the execve succeeds.  For this reason, the call ``fcntl(d, F_SETFD,
     1)'' is provided, which arranges that a descriptor will be closed after a successful execve; the call ``fcntl(d, F_SETFD, 0)'' restores the
     default, which is to not close the descriptor.

RETURN VALUES

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

ERRORS

     The close() system call will fail if:

     [EBADF]		fildes is not a valid, active file descriptor.

     [EINTR]		Its execution was interrupted by a signal.

     [EIO]		A previously-uncommitted write(2) encountered an input/output error.

SEE ALSO

     accept(2), execve(2), fcntl(2), flock(2), open(2), pipe(2), socket(2), socketpair(2)

STANDARDS

     Close() conforms to IEEE Std 1003.1-1988 (``POSIX.1'').

4th Berkeley Distribution					  April 19, 1994					 4th Berkeley Distribution