1.\" Copyright (c) 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)confstr.3 8.1 (Berkeley) 6/4/93 29.\" $FreeBSD: src/lib/libc/gen/confstr.3,v 1.15 2007/01/09 00:27:53 imp Exp $ 30.\" $DragonFly: src/lib/libc/gen/confstr.3,v 1.6 2008/05/02 02:05:03 swildner Exp $ 31.\" 32.Dd December 6, 2006 33.Dt CONFSTR 3 34.Os 35.Sh NAME 36.Nm confstr 37.Nd get string-valued configurable variables 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In unistd.h 42.Ft size_t 43.Fn confstr "int name" "char *buf" "size_t len" 44.Sh DESCRIPTION 45This interface is specified by 46.St -p1003.1-2001 . 47A more flexible (but non-portable) interface is provided by 48.Xr sysctl 3 . 49.Pp 50The 51.Fn confstr 52function provides a method for applications to get configuration 53defined string values. 54Shell programmers needing access to these parameters should use the 55.Xr getconf 1 56utility. 57.Pp 58The 59.Fa name 60argument specifies the system variable to be queried. 61Symbolic constants for each name value are found in the include file 62.In unistd.h . 63The 64.Fa len 65argument specifies the size of the buffer referenced by the 66argument 67.Fa buf . 68If 69.Fa len 70is non-zero, 71.Fa buf 72is a non-null pointer, and 73.Fa name 74has a value, up to 75.Fa len 76\- 1 bytes of the value are copied into the buffer 77.Fa buf . 78The copied value is always null terminated. 79.Pp 80The available values are as follows: 81.Bl -tag -width 6n 82.It Li _CS_PATH 83Return a value for the 84.Ev PATH 85environment variable that finds all the standard utilities. 86.El 87.Sh RETURN VALUES 88If the call to 89.Fn confstr 90is not successful, 0 is returned and 91.Va errno 92is set appropriately. 93Otherwise, if the variable does not have a configuration defined value, 940 is returned and 95.Va errno 96is not modified. 97Otherwise, the buffer size needed to hold the entire configuration-defined 98value is returned. 99If this size is greater than the argument 100.Fa len , 101the string in 102.Fa buf 103was truncated. 104.Sh ERRORS 105The 106.Fn confstr 107function may fail and set 108.Va errno 109for any of the errors specified for the library functions 110.Xr malloc 3 111and 112.Xr sysctl 3 . 113.Pp 114In addition, the following errors may be reported: 115.Bl -tag -width Er 116.It Bq Er EINVAL 117The value of the 118.Fa name 119argument is invalid. 120.El 121.Sh SEE ALSO 122.Xr getconf 1 , 123.Xr pathconf 2 , 124.Xr sysconf 3 , 125.Xr sysctl 3 126.Sh STANDARDS 127The 128.Fn confstr 129function conforms to 130.St -susv3 . 131.Sh HISTORY 132The 133.Fn confstr 134function first appeared in 135.Bx 4.4 . 136