xref: /illumos-gate/usr/src/man/man4d/null.4d (revision b93865c3d90e9b0d73e338c9abb3293c35c571a8)
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Copyright 1989 AT&T
Copyright (C) 2001, Sun Microsystems, Inc.
All Rights Reserved
The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). You may not use this file except in compliance with the License.
You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing. See the License for the specific language governing permissions and limitations under the License.
When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
NULL 4D "Apr 4, 2001"
NAME
null - the null file, also called the null device
SYNOPSIS

/dev/null
DESCRIPTION

Data written on the null special file, /dev/null, is discarded.

Reads from a null special file always return 0 bytes.

Mapping a null special file creates an address reservation of a length equal to the length of the mapping, and rounded up to the nearest page size as returned by sysconf(3C). No resources are consumed by the reservation. Mappings can be placed in the resulting address range via subsequent calls to mmap with the -MAP_FIXED option set.

FILES
/dev/null

SEE ALSO

mmap (2), sysconf (3C)