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.\" @(#)pathconf.2 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD$ 34.\" 35.Dd June 4, 1993 36.Dt PATHCONF 2 37.Os 38.Sh NAME 39.Nm pathconf , 40.Nm fpathconf 41.Nd get configurable pathname variables 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.Fd #include <unistd.h> 46.Ft long 47.Fn pathconf "const char *path" "int name" 48.Ft long 49.Fn fpathconf "int fd" "int name" 50.Sh DESCRIPTION 51The 52.Fn pathconf 53and 54.Fn fpathconf 55functions provides a method for applications to determine the current 56value of a configurable system limit or option variable associated 57with a pathname or file descriptor. 58.Pp 59For 60.Fn pathconf , 61the 62.Fa path 63argument is the name of a file or directory. 64For 65.Fn fpathconf , 66the 67.Fa fd 68argument is an open file descriptor. 69The 70.Fa name 71argument specifies the system variable to be queried. 72Symbolic constants for each name value are found in the include file 73.Li <unistd.h> . 74.Pp 75The available values are as follows: 76.Pp 77.Bl -tag -width 6n 78.Pp 79.It Li _PC_LINK_MAX 80The maximum file link count. 81.It Li _PC_MAX_CANON 82The maximum number of bytes in terminal canonical input line. 83.It Li _PC_MAX_INPUT 84The minimum maximum number of bytes for which space is available in 85a terminal input queue. 86.It Li _PC_NAME_MAX 87The maximum number of bytes in a file name. 88.It Li _PC_PATH_MAX 89The maximum number of bytes in a pathname. 90.It Li _PC_PIPE_BUF 91The maximum number of bytes which will be written atomically to a pipe. 92.It Li _PC_CHOWN_RESTRICTED 93Return 1 if appropriate privileges are required for the 94.Xr chown 2 95system call, otherwise 0. 96.It Li _PC_NO_TRUNC 97Return 1 if file names longer than KERN_NAME_MAX are truncated. 98.It Li _PC_VDISABLE 99Returns the terminal character disabling value. 100.El 101.Sh RETURN VALUES 102If the call to 103.Fn pathconf 104or 105.Fn fpathconf 106is not successful, \-1 is returned and 107.Va errno 108is set appropriately. 109Otherwise, if the variable is associated with functionality that does 110not have a limit in the system, \-1 is returned and 111.Va errno 112is not modified. 113Otherwise, the current variable value is returned. 114.Sh ERRORS 115If any of the following conditions occur, the 116.Fn pathconf 117and 118.Fn fpathconf 119functions shall return -1 and set 120.Va errno 121to the corresponding value. 122.Bl -tag -width Er 123.It Bq Er EINVAL 124The value of the 125.Fa name 126argument is invalid. 127.It Bq Er EINVAL 128The implementation does not support an association of the variable 129name with the associated file. 130.El 131.Pp 132.Fn Pathconf 133will fail if: 134.Bl -tag -width Er 135.It Bq Er ENOTDIR 136A component of the path prefix is not a directory. 137.It Bq Er ENAMETOOLONG 138A component of a pathname exceeded 255 characters, 139or an entire path name exceeded 1023 characters. 140.It Bq Er ENOENT 141The named file does not exist. 142.It Bq Er EACCES 143Search permission is denied for a component of the path prefix. 144.It Bq Er ELOOP 145Too many symbolic links were encountered in translating the pathname. 146.It Bq Er EIO 147An I/O error occurred while reading from or writing to the file system. 148.El 149.Pp 150.Bl -tag -width Er 151.Fn Fpathconf 152will fail if: 153.It Bq Er EBADF 154.Fa fd 155is not a valid open file descriptor. 156.It Bq Er EIO 157An I/O error occurred while reading from or writing to the file system. 158.El 159.Sh SEE ALSO 160.Xr sysctl 3 161.Sh HISTORY 162The 163.Fn pathconf 164and 165.Fn fpathconf 166functions first appeared in 167.Bx 4.4 . 168