netbsd man page for close

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

NAME
     close -- delete a descriptor

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <unistd.h>

     int
     close(int d);

DESCRIPTION
     The close() system 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 flock(2)).

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

     When a process calls 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 only if the execve() succeeds.  For this reason, the system
     call

	   fcntl(d, F_SETFD, 1);

     is provided, which arranges that a descriptor ``d'' will be closed after a successful execve(); the system call

	   fcntl(d, F_SETFD, 0);

     restores the default, which is to not close descriptor ``d''.

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

ERRORS
     close() will fail if:

     [EBADF]		d is not an active descriptor.

     [EINTR]		An interrupt was received.

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

STANDARDS
     The close() function conforms to ISO/IEC 9945-1:1990 (``POSIX.1'').

BSD
								  April 19, 1994							       BSD