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 BSD 4 38.Sh NAME 39.Nm confstr 40.Nd get string-valued configurable variables 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.Fd #include <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 -p1003.1-200x . 50.Tn POSIX . 51A more flexible (but non-portable) interface is provided by 52.Xr sysctl 3 . 53.Pp 54The 55.Fn confstr 56function provides a method for applications to get configuration 57defined string values. 58Shell programmers needing access to these parameters should use the 59.Xr getconf 1 60utility. 61.Pp 62The 63.Fa name 64argument specifies the system variable to be queried. 65Symbolic constants for each name value are found in the include file 66.Aq Pa unistd.h . 67The 68.Fa len 69argument specifies the size of the buffer referenced by the 70argument 71.Fa buf . 72If 73.Fa len 74is non-zero, 75.Fa buf 76is a non-null pointer, and 77.Fa name 78has a value, up to 79.Fa len 80\- 1 bytes of the value are copied into the buffer 81.Fa buf . 82The copied value is always null terminated. 83.Pp 84The available values are as follows: 85.Pp 86.Bl -tag -width 6n 87.Pp 88.It Li _CS_PATH 89Return a value for the 90.Ev PATH 91environment variable that finds all the standard utilities. 92.El 93.Sh RETURN VALUES 94If the call to 95.Fn confstr 96is not successful, \-1 is returned and 97.Va errno 98is set appropriately. 99Otherwise, if the variable does not have a configuration defined value, 1000 is returned and 101.Va errno 102is not modified. 103Otherwise, the buffer size needed to hold the entire configuration-defined 104value is returned. 105If this size is greater than the argument 106.Fa len , 107the string in 108.Fa buf 109was truncated. 110.Sh ERRORS 111The 112.Fn confstr 113function may fail and set 114.Va errno 115for any of the errors specified for the library functions 116.Xr malloc 3 117and 118.Xr sysctl 3 . 119.Pp 120In addition, the following errors may be reported: 121.Bl -tag -width Er 122.It Bq Er EINVAL 123The value of the 124.Fa name 125argument is invalid. 126.El 127.Sh SEE ALSO 128.Xr getconf 1 , 129.Xr pathconf 2 , 130.Xr sysconf 3 , 131.Xr sysctl 3 132.Sh HISTORY 133The 134.Fn confstr 135function first appeared in 136.Bx 4.4 . 137