137 lines
3.9 KiB
Groff
137 lines
3.9 KiB
Groff
.\" Copyright (c) 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)confstr.3 8.1 (Berkeley) 6/4/93
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.\" $FreeBSD$
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.\"
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.Dd June 18, 2001
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.Dt CONFSTR 3
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.Os
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.Sh NAME
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.Nm confstr
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.Nd get string-valued configurable variables
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.Fd #include <unistd.h>
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.Ft size_t
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.Fn confstr "int name" "char *buf" "size_t len"
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.Sh DESCRIPTION
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This interface is specified by
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.\" .St -p1003.1-200x .
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.Tn POSIX .
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A more flexible (but non-portable) interface is provided by
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.Xr sysctl 3 .
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.Pp
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The
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.Fn confstr
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function provides a method for applications to get configuration
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defined string values.
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Shell programmers needing access to these parameters should use the
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.Xr getconf 1
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utility.
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.Pp
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The
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.Fa name
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argument specifies the system variable to be queried.
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Symbolic constants for each name value are found in the include file
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.Aq Pa unistd.h .
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The
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.Fa len
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argument specifies the size of the buffer referenced by the
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argument
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.Fa buf .
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If
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.Fa len
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is non-zero,
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.Fa buf
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is a non-null pointer, and
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.Fa name
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has a value, up to
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.Fa len
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\- 1 bytes of the value are copied into the buffer
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.Fa buf .
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The copied value is always null terminated.
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.Pp
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The available values are as follows:
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.Pp
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.Bl -tag -width 6n
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.Pp
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.It Li _CS_PATH
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Return a value for the
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.Ev PATH
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environment variable that finds all the standard utilities.
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.El
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.Sh RETURN VALUES
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If the call to
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.Fn confstr
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is not successful, \-1 is returned and
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.Va errno
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is set appropriately.
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Otherwise, if the variable does not have a configuration defined value,
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0 is returned and
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.Va errno
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is not modified.
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Otherwise, the buffer size needed to hold the entire configuration-defined
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value is returned.
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If this size is greater than the argument
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.Fa len ,
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the string in
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.Fa buf
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was truncated.
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.Sh ERRORS
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The
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.Fn confstr
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function may fail and set
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.Va errno
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for any of the errors specified for the library functions
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.Xr malloc 3
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and
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.Xr sysctl 3 .
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.Pp
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In addition, the following errors may be reported:
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.Bl -tag -width Er
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.It Bq Er EINVAL
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The value of the
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.Fa name
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argument is invalid.
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.El
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.Sh SEE ALSO
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.Xr getconf 1 ,
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.Xr pathconf 2 ,
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.Xr sysconf 3 ,
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.Xr sysctl 3
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.Sh HISTORY
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The
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.Fn confstr
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function first appeared in
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.Bx 4.4 .
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