.\" Copyright (c) 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" 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. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the University of .\" California, Berkeley and its contributors. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. .\" .\" @(#)confstr.3 8.1 (Berkeley) 6/4/93 .\" $FreeBSD: src/lib/libc/gen/confstr.3,v 1.11 2001/10/01 16:08:50 ru Exp $ .\" .Dd June 18, 2001 .Dt CONFSTR 3 .Os .Sh NAME .Nm confstr .Nd get string-valued configurable variables .Sh LIBRARY .Lb libc .Sh SYNOPSIS .In unistd.h .Ft size_t .Fn confstr "int name" "char *buf" "size_t len" .Sh DESCRIPTION This interface is specified by .\" .St -p1003.1-200x . .Tn POSIX . A more flexible (but non-portable) interface is provided by .Xr sysctl 3 . .Pp The .Fn confstr function provides a method for applications to get configuration defined string values. Shell programmers needing access to these parameters should use the .Xr getconf 1 utility. .Pp The .Fa name argument specifies the system variable to be queried. Symbolic constants for each name value are found in the include file .Aq Pa unistd.h . The .Fa len argument specifies the size of the buffer referenced by the argument .Fa buf . If .Fa len is non-zero, .Fa buf is a non-null pointer, and .Fa name has a value, up to .Fa len \- 1 bytes of the value are copied into the buffer .Fa buf . The copied value is always null terminated. .Pp The available values are as follows: .Pp .Bl -tag -width 6n .Pp .It Li _CS_PATH Return a value for the .Ev PATH environment variable that finds all the standard utilities. .El .Sh RETURN VALUES If the call to .Fn confstr is not successful, 0 is returned and .Va errno is set appropriately. Otherwise, if the variable does not have a configuration defined value, 0 is returned and .Va errno is not modified. Otherwise, the buffer size needed to hold the entire configuration-defined value is returned. If this size is greater than the argument .Fa len , the string in .Fa buf was truncated. .Sh ERRORS The .Fn confstr function may fail and set .Va errno for any of the errors specified for the library functions .Xr malloc 3 and .Xr sysctl 3 . .Pp In addition, the following errors may be reported: .Bl -tag -width Er .It Bq Er EINVAL The value of the .Fa name argument is invalid. .El .Sh LEGACY ERRORS If the call to .Fn confstr is not successful, \-1 (rather than 0) is returned and .Va errno is set appropriately. .Sh SEE ALSO .Xr getconf 1 , .Xr pathconf 2 , .Xr sysconf 3 , .Xr sysctl 3 .Sh HISTORY The .Fn confstr function first appeared in .Bx 4.4 .