1.\" Copyright (c) 1980, 1991, 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.\" @(#)umask.2 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD$ 34.\" 35.Dd June 4, 1993 36.Dt UMASK 2 37.Os 38.Sh NAME 39.Nm umask 40.Nd set file creation mode mask 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In sys/stat.h 45.Ft mode_t 46.Fn umask "mode_t numask" 47.Sh DESCRIPTION 48The 49.Fn umask 50routine sets the process's file mode creation mask to 51.Fa numask 52and returns the previous value of the mask. 53The 9 low-order 54access permission 55bits of 56.Fa numask 57are used by system calls, including 58.Xr open 2 , 59.Xr mkdir 2 , 60and 61.Xr mkfifo 2 , 62to turn off corresponding bits 63requested in file mode. 64(See 65.Xr chmod 2 ) . 66This clearing allows each user to restrict the default access 67to his files. 68.Pp 69The default mask value is S_IWGRP|S_IWOTH (022, write access for the 70owner only). 71Child processes inherit the mask of the calling process. 72.Sh RETURN VALUES 73The previous value of the file mode mask is returned by the call. 74.Sh ERRORS 75The 76.Fn umask 77system call is always successful. 78.Sh SEE ALSO 79.Xr chmod 2 , 80.Xr mknod 2 , 81.Xr open 2 82.Sh STANDARDS 83The 84.Fn umask 85system call is expected to conform to 86.St -p1003.1-90 . 87.Sh HISTORY 88The 89.Fn umask 90function appeared in 91.At v7 . 92