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.\" 30.Dd December 3, 2006 31.Dt CONFSTR 3 32.Os 33.Sh NAME 34.Nm confstr 35.Nd get string-valued configurable variables 36.Sh LIBRARY 37.Lb libc 38.Sh SYNOPSIS 39.In unistd.h 40.Ft size_t 41.Fn confstr "int name" "char *buf" "size_t len" 42.Sh DESCRIPTION 43This interface is specified by 44.St -p1003.1-2001 . 45A more flexible (but non-portable) interface is provided by 46.Xr sysctl 3 . 47.Pp 48The 49.Fn confstr 50function provides a method for applications to get configuration 51defined string values. 52Shell programmers needing access to these parameters should use the 53.Xr getconf 1 54utility. 55.Pp 56The 57.Fa name 58argument specifies the system variable to be queried. 59Symbolic constants for each name value are found in the include file 60.In unistd.h . 61The 62.Fa len 63argument specifies the size of the buffer referenced by the 64argument 65.Fa buf . 66If 67.Fa len 68is non-zero, 69.Fa buf 70is a non-null pointer, and 71.Fa name 72has a value, up to 73.Fa len 74\- 1 bytes of the value are copied into the buffer 75.Fa buf . 76The copied value is always null terminated. 77.Pp 78The available values are as follows: 79.Bl -tag -width 6n 80.It Li _CS_PATH 81Return a value for the 82.Ev PATH 83environment variable that finds all the standard utilities. 84.El 85.Sh RETURN VALUES 86If the call to 87.Fn confstr 88is not successful, 0 is returned and 89.Va errno 90is set appropriately. 91Otherwise, if the variable does not have a configuration defined value, 920 is returned and 93.Va errno 94is not modified. 95Otherwise, the buffer size needed to hold the entire configuration-defined 96value is returned. 97If this size is greater than the argument 98.Fa len , 99the string in 100.Fa buf 101was truncated. 102.Sh ERRORS 103The 104.Fn confstr 105function may fail and set 106.Va errno 107for any of the errors specified for the library functions 108.Xr malloc 3 109and 110.Xr sysctl 3 . 111.Pp 112In addition, the following errors may be reported: 113.Bl -tag -width Er 114.It Bq Er EINVAL 115The value of the 116.Fa name 117argument is invalid. 118.El 119.Sh SEE ALSO 120.Xr getconf 1 , 121.Xr pathconf 2 , 122.Xr sysconf 3 , 123.Xr sysctl 3 124.Sh HISTORY 125The 126.Fn confstr 127function first appeared in 128.Bx 4.4 . 129