1.\" Copyright (c) 1980, 1991 Regents of the University of California. 2.\" 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.\" from: @(#)umask.2 6.2 (Berkeley) 3/10/91 33.\" $Id: umask.2,v 1.3 1993/10/05 16:38:01 jtc Exp $ 34.\" 35.Dd March 10, 1991 36.Dt UMASK 2 37.Os BSD 4 38.Sh NAME 39.Nm umask 40.Nd set file creation mode mask 41.Sh SYNOPSIS 42.Fd #include <sys/types.h> 43.Fd #include <sys/stat.h> 44.Ft mode_t 45.Fn umask "mode_t numask" 46.Sh DESCRIPTION 47The 48.Fn umask 49routine sets the process's file mode creation mask to 50.Fa numask 51and returns the previous value of the mask. The 9 low-order 52access permission 53bits of 54.Fa numask 55are used by system calls, including 56.Xr open 2 , 57.Xr mkdir 2 , 58and 59.Xr mkfifo 2 , 60to turn off corresponding bits 61requested in file mode. 62(see 63.Xr chmod 2 ) . 64This clearing allows each user to restrict the default access 65to his files. 66.Pp 67The default mask value is 022 (write access for owner only). 68Child processes inherit the mask of the calling process. 69.Sh RETURN VALUES 70The previous value of the file mode mask is returned by the call. 71.Sh ERRORS 72The 73.Fn umask 74function is always successful. 75.Sh SEE ALSO 76.Xr chmod 2 , 77.Xr mknod 2 , 78.Xr open 2 79.Sh STANDARDS 80The 81.Fn umask 82function call is expected to 83conform to IEEE Std 1003.1-1988 84.Pq Dq Tn POSIX . 85