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.Dd December 3, 2006 29.Dt CONFSTR 3 30.Os 31.Sh NAME 32.Nm confstr 33.Nd get string-valued configurable variables 34.Sh LIBRARY 35.Lb libc 36.Sh SYNOPSIS 37.In unistd.h 38.Ft size_t 39.Fn confstr "int name" "char *buf" "size_t len" 40.Sh DESCRIPTION 41This interface is specified by 42.St -p1003.1-2001 . 43A more flexible (but non-portable) interface is provided by 44.Xr sysctl 3 . 45.Pp 46The 47.Fn confstr 48function provides a method for applications to get configuration 49defined string values. 50Shell programmers needing access to these parameters should use the 51.Xr getconf 1 52utility. 53.Pp 54The 55.Fa name 56argument specifies the system variable to be queried. 57Symbolic constants for each name value are found in the include file 58.In unistd.h . 59The 60.Fa len 61argument specifies the size of the buffer referenced by the 62argument 63.Fa buf . 64If 65.Fa len 66is non-zero, 67.Fa buf 68is a non-null pointer, and 69.Fa name 70has a value, up to 71.Fa len 72\- 1 bytes of the value are copied into the buffer 73.Fa buf . 74The copied value is always null terminated. 75.Pp 76The available values are as follows: 77.Bl -tag -width 6n 78.It Li _CS_PATH 79Return a value for the 80.Ev PATH 81environment variable that finds all the standard utilities. 82.El 83.Sh RETURN VALUES 84If the call to 85.Fn confstr 86is not successful, 0 is returned and 87.Va errno 88is set appropriately. 89Otherwise, if the variable does not have a configuration defined value, 900 is returned and 91.Va errno 92is not modified. 93Otherwise, the buffer size needed to hold the entire configuration-defined 94value is returned. 95If this size is greater than the argument 96.Fa len , 97the string in 98.Fa buf 99was truncated. 100.Sh ERRORS 101The 102.Fn confstr 103function may fail and set 104.Va errno 105for any of the errors specified for the library functions 106.Xr malloc 3 107and 108.Xr sysctl 3 . 109.Pp 110In addition, the following errors may be reported: 111.Bl -tag -width Er 112.It Bq Er EINVAL 113The value of the 114.Fa name 115argument is invalid. 116.El 117.Sh SEE ALSO 118.Xr getconf 1 , 119.Xr pathconf 2 , 120.Xr sysconf 3 , 121.Xr sysctl 3 122.Sh HISTORY 123The 124.Fn confstr 125function first appeared in 126.Bx 4.4 . 127