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.\" $FreeBSD: head/lib/libc/gen/feature_present.3 222286 2011-05-25 14:13:53Z ru $
.\"
.Dd January 8, 2008
.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 .