1.\" $NetBSD: unistd.3,v 1.4 2011/08/09 18:11:38 jruoho Exp $ 2.\" 3.\" Copyright (c) 2011 Jukka Ruohonen <jruohonen@iki.fi> 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 16.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 17.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 18.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 19.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 20.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 21.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 22.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 23.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 24.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 25.\" POSSIBILITY OF SUCH DAMAGE. 26.\" 27.Dd August 9, 2011 28.Dt UNISTD 3 29.Os 30.Sh NAME 31.Nm unistd 32.Nd standard symbolic constants and types 33.Sh SYNOPSIS 34.In unistd.h 35.Sh DESCRIPTION 36The 37.In unistd.h 38header forms the basis of the Portable Operating System Interface for Unix 39.Pq Tn POSIX 40.Tn API . 41It includes definitions for numerous functions, symbolic constants, and types. 42Among these are: 43.Bl -bullet -offset indent 44.It 45The implementation-defined 46.Dv NULL 47pointer constant. 48.It 49Types such as 50.Vt size_t , 51.Vt ssize_t , 52.Vt pid_t , 53and 54.Vt intptr_t . 55.It 56Various limits and other symbolic constants described in 57.Xr pathconf 2 58and 59.Xr sysconf 3 . 60.It 61Prototypes for several important system calls and library routines such as 62.Xr chown 2 , 63.Xr dup 2 , 64.Xr execl 3 , 65.Xr fork 2 , 66.Xr pipe 2 , 67.Xr rmdir 2 , 68.Xr setuid 2 , 69and 70.Xr write 2 . 71.It 72The symbolic constant 73.Dv _POSIX_VERSION 74that defines the version of the 75.Tn POSIX 76standard to which the implementation conforms. 77.It 78Various other 79.Dv _POSIX 80-prefixed symbolic constants that indicate whether 81the system implements some optional part of the standard. 82Examples include such constants as 83.Dv _POSIX_IPV6 84for 85.Xr inet6 4 86functionality and 87.Dv _POSIX_ASYNCHRONOUS_IO 88for 89.Xr aio 3 . 90.El 91.Sh SEE ALSO 92.Xr limits 3 , 93.Xr stddef 3 , 94.Xr stdint 3 , 95.Xr stdlib 3 , 96.Xr types 3 97.Sh STANDARDS 98The 99.In unistd.h 100header conforms to 101.St -p1003.1-2001 . 102.\" 103.\" XXX: fill this. 104.\" 105.\".Sh HISTORY 106.\" A 107.\" .In unistd.h 108.\" header first appeared in 109.\" ??? 110