Return to close.2 CVS log

Up to [CSRG BSD Unix] / 43BSDTahoe / man / man2

Annotation of 43BSDTahoe/man/man2/close.2, revision 1.1.1.1

1.1       root        1: .\" Copyright (c) 1980 Regents of the University of California.
                      2: .\" All rights reserved.  The Berkeley software License Agreement
                      3: .\" specifies the terms and conditions for redistribution.
                      4: .\"
                      5: .\"    @(#)close.2     6.3 (Berkeley) 5/22/86
                      6: .\"
                      7: .TH CLOSE 2 "May 22, 1986"
                      8: .UC 4
                      9: .SH NAME
                     10: close \- delete a descriptor
                     11: .SH SYNOPSIS
                     12: .B close(d)
                     13: .br
                     14: .B "int d;"
                     15: .SH DESCRIPTION
                     16: The
                     17: \fIclose\fP call deletes a descriptor from the per-process object
                     18: reference table.
                     19: If this is the last reference to the underlying object, then
                     20: it will be deactivated.
                     21: For example, on the last close of a file
                     22: the current \fIseek\fP pointer associated with the file is lost;
                     23: on the last close of a
                     24: .IR socket (2)
                     25: associated naming information and queued data are discarded;
                     26: on the last close of a file holding an advisory lock
                     27: the lock is released (see further
                     28: .IR flock (2)\fR).
                     29: .PP
                     30: A close of all of a process's descriptors is automatic on
                     31: .IR exit ,
                     32: but since
                     33: there is a limit on the number of active descriptors per process,
                     34: .I close
                     35: is necessary for programs that deal with many descriptors.
                     36: .PP
                     37: When a process forks (see
                     38: .IR fork (2)),
                     39: all descriptors for the new child process reference the same
                     40: objects as they did in the parent before the fork.
                     41: If a new process is then to be run using
                     42: .IR execve (2),
                     43: the process would normally inherit these descriptors.  Most
                     44: of the descriptors can be rearranged with
                     45: .IR dup2 (2)
                     46: or deleted with
                     47: .I close
                     48: before the
                     49: .I execve
                     50: is attempted, but if some of these descriptors will still
                     51: be needed if the execve fails, it is necessary to arrange for them
                     52: to be closed if the execve succeeds.
                     53: For this reason, the call ``fcntl(d, F_SETFD, 1)'' is provided,
                     54: which arranges that a descriptor will be closed after a successful
                     55: execve; the call ``fcntl(d, F_SETFD, 0)'' restores the default,
                     56: which is to not close the descriptor.
                     57: .SH "RETURN VALUE
                     58: Upon successful completion, a value of 0 is returned.
                     59: Otherwise, a value of \-1 is returned and the global integer variable
                     60: .I errno
                     61: is set to indicate the error.
                     62: .SH ERRORS
                     63: .I Close
                     64: will fail if:
                     65: .TP 15
                     66: [EBADF]
                     67: \fID\fP is not an active descriptor.
                     68: .SH "SEE ALSO"
                     69: accept(2), flock(2), open(2), pipe(2), socket(2), socketpair(2),
                     70: execve(2), fcntl(2)

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.