freebsd-dev/lib/libc/gen/feature_present.3

73 lines
2.5 KiB
Groff
Raw Normal View History

.\" Copyright (c) 2008 Yahoo!, Inc.
.\" All rights reserved.
.\" Written by: John Baldwin <jhb@FreeBSD.org>
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the author nor the names of any co-contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd January 8, 2008
2011-05-25 14:13:53 +00:00
.Dt FEATURE_PRESENT 3
.Os
.Sh NAME
.Nm feature_present
.Nd query presence of a kernel feature
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In unistd.h
.Ft int
.Fn feature_present "const char *feature"
.Sh DESCRIPTION
The
.Fn feature_present
function provides a method for an application to determine if a specific
kernel feature is present in the currently running kernel.
The
.Fa feature
argument specifies the name of the feature to check.
The
.Fn feature_present
function will return 1 if the specified feature is present,
otherwise it will return 0.
If the
.Fn feature_present
function is not able to determine the presence of
.Fa feature
due to an internal error it will return 0.
.Sh RETURN VALUES
If
.Fa feature
is present then 1 is returned;
otherwise 0 is returned.
.Sh SEE ALSO
.Xr sysconf 3 ,
.Xr sysctl 3
.Sh HISTORY
The
.Fn feature_present
function first appeared in
.Fx 8.0 .