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.\" 31.Dd December 6, 2006 32.Dt CONFSTR 3 33.Os 34.Sh NAME 35.Nm confstr 36.Nd get string-valued configurable variables 37.Sh LIBRARY 38.Lb libc 39.Sh SYNOPSIS 40.In unistd.h 41.Ft size_t 42.Fn confstr "int name" "char *buf" "size_t len" 43.Sh DESCRIPTION 44This interface is specified by 45.St -p1003.1-2001 . 46A more flexible (but non-portable) interface is provided by 47.Xr sysctl 3 . 48.Pp 49The 50.Fn confstr 51function provides a method for applications to get configuration 52defined string values. 53Shell programmers needing access to these parameters should use the 54.Xr getconf 1 55utility. 56.Pp 57The 58.Fa name 59argument specifies the system variable to be queried. 60Symbolic constants for each name value are found in the include file 61.In unistd.h . 62The 63.Fa len 64argument specifies the size of the buffer referenced by the 65argument 66.Fa buf . 67If 68.Fa len 69is non-zero, 70.Fa buf 71is a non-null pointer, and 72.Fa name 73has a value, up to 74.Fa len 75\- 1 bytes of the value are copied into the buffer 76.Fa buf . 77The copied value is always null terminated. 78.Pp 79The available values are as follows: 80.Bl -tag -width 6n 81.It Dv _CS_PATH 82Return a value for the 83.Ev PATH 84environment variable that finds all the standard utilities. 85.El 86.Sh RETURN VALUES 87If the call to 88.Fn confstr 89is not successful, 0 is returned and 90.Va errno 91is set appropriately. 92Otherwise, if the variable does not have a configuration defined value, 930 is returned and 94.Va errno 95is not modified. 96Otherwise, the buffer size needed to hold the entire configuration-defined 97value is returned. 98If this size is greater than the argument 99.Fa len , 100the string in 101.Fa buf 102was truncated. 103.Sh ERRORS 104The 105.Fn confstr 106function may fail and set 107.Va errno 108for any of the errors specified for the library functions 109.Xr malloc 3 110and 111.Xr sysctl 3 . 112.Pp 113In addition, the following errors may be reported: 114.Bl -tag -width Er 115.It Bq Er EINVAL 116The value of the 117.Fa name 118argument is invalid. 119.El 120.Sh SEE ALSO 121.Xr getconf 1 , 122.Xr pathconf 2 , 123.Xr sysconf 3 , 124.Xr sysctl 3 125.Sh STANDARDS 126The 127.Fn confstr 128function conforms to 129.St -susv3 . 130.Sh HISTORY 131The 132.Fn confstr 133function first appeared in 134.Bx 4.4 . 135