1.\" $NetBSD: umask.2,v 1.16 2003/08/07 16:44:10 agc Exp $ 2.\" 3.\" Copyright (c) 1980, 1991, 1993 4.\" The Regents of the University of California. 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.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)umask.2 8.1 (Berkeley) 6/4/93 31.\" 32.Dd June 4, 1993 33.Dt UMASK 2 34.Os 35.Sh NAME 36.Nm umask 37.Nd set file creation mode mask 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In sys/stat.h 42.Ft mode_t 43.Fn umask "mode_t numask" 44.Sh DESCRIPTION 45The 46.Fn umask 47routine sets the process's file mode creation mask to 48.Fa numask 49and returns the previous value of the mask. 50The 9 low-order access permission bits of 51.Fa numask 52are used by system calls, including 53.Xr open 2 , 54.Xr mkdir 2 , 55.Xr mkfifo 2 56and 57.Xr mknod 2 58to turn off corresponding bits 59requested in file mode. 60(See 61.Xr chmod 2 ) . 62This clearing allows each user to restrict the default access 63to his files. 64.Pp 65The default mask value is S_IWGRP|S_IWOTH (022, write access for the 66owner only). 67Child processes inherit the mask of the calling process. 68.Sh RETURN VALUES 69The previous value of the file mode mask is returned by the call. 70.Sh ERRORS 71The 72.Fn umask 73function is always successful. 74.Sh SEE ALSO 75.Xr chmod 2 , 76.Xr mkdir 2 , 77.Xr mkfifo 2 , 78.Xr mknod 2 , 79.Xr open 2 80.Sh STANDARDS 81The 82.Fn umask 83function conforms to 84.St -p1003.1-90 . 85