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. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)confstr.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD$ 34.\" 35.Dd June 18, 2001 36.Dt CONFSTR 3 37.Os 38.Sh NAME 39.Nm confstr 40.Nd get string-valued configurable variables 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In unistd.h 45.Ft size_t 46.Fn confstr "int name" "char *buf" "size_t len" 47.Sh DESCRIPTION 48This interface is specified by 49.St -p1003.1-2001 . 50A more flexible (but non-portable) interface is provided by 51.Xr sysctl 3 . 52.Pp 53The 54.Fn confstr 55function provides a method for applications to get configuration 56defined string values. 57Shell programmers needing access to these parameters should use the 58.Xr getconf 1 59utility. 60.Pp 61The 62.Fa name 63argument specifies the system variable to be queried. 64Symbolic constants for each name value are found in the include file 65.Aq Pa unistd.h . 66The 67.Fa len 68argument specifies the size of the buffer referenced by the 69argument 70.Fa buf . 71If 72.Fa len 73is non-zero, 74.Fa buf 75is a non-null pointer, and 76.Fa name 77has a value, up to 78.Fa len 79\- 1 bytes of the value are copied into the buffer 80.Fa buf . 81The copied value is always null terminated. 82.Pp 83The available values are as follows: 84.Pp 85.Bl -tag -width 6n 86.Pp 87.It Li _CS_PATH 88Return a value for the 89.Ev PATH 90environment variable that finds all the standard utilities. 91.El 92.Sh RETURN VALUES 93If the call to 94.Fn confstr 95is not successful, \-1 is returned and 96.Va errno 97is set appropriately. 98Otherwise, if the variable does not have a configuration defined value, 990 is returned and 100.Va errno 101is not modified. 102Otherwise, the buffer size needed to hold the entire configuration-defined 103value is returned. 104If this size is greater than the argument 105.Fa len , 106the string in 107.Fa buf 108was truncated. 109.Sh ERRORS 110The 111.Fn confstr 112function may fail and set 113.Va errno 114for any of the errors specified for the library functions 115.Xr malloc 3 116and 117.Xr sysctl 3 . 118.Pp 119In addition, the following errors may be reported: 120.Bl -tag -width Er 121.It Bq Er EINVAL 122The value of the 123.Fa name 124argument is invalid. 125.El 126.Sh SEE ALSO 127.Xr getconf 1 , 128.Xr pathconf 2 , 129.Xr sysconf 3 , 130.Xr sysctl 3 131.Sh HISTORY 132The 133.Fn confstr 134function first appeared in 135.Bx 4.4 . 136