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. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)umask.2 8.1 (Berkeley) 6/4/93 29.\" 30.Dd June 4, 1993 31.Dt UMASK 2 32.Os 33.Sh NAME 34.Nm umask 35.Nd set file creation mode mask 36.Sh LIBRARY 37.Lb libc 38.Sh SYNOPSIS 39.In sys/stat.h 40.Ft mode_t 41.Fn umask "mode_t numask" 42.Sh DESCRIPTION 43The 44.Fn umask 45routine sets the process's file mode creation mask to 46.Fa numask 47and returns the previous value of the mask. 48The 9 low-order 49access permission 50bits of 51.Fa numask 52are used by system calls, including 53.Xr open 2 , 54.Xr mkdir 2 , 55and 56.Xr mkfifo 2 , 57to turn off corresponding bits 58requested in file mode. 59(See 60.Xr chmod 2 ) . 61This clearing allows each user to restrict the default access 62to his files. 63.Pp 64The default mask value is S_IWGRP|S_IWOTH (022, write access for the 65owner only). 66Child processes inherit the mask of the calling process. 67.Sh RETURN VALUES 68The previous value of the file mode mask is returned by the call. 69.Sh ERRORS 70The 71.Fn umask 72system call is always successful. 73.Sh SEE ALSO 74.Xr chmod 2 , 75.Xr mkfifo 2 , 76.Xr mknod 2 , 77.Xr open 2 78.Sh STANDARDS 79The 80.Fn umask 81system call is expected to conform to 82.St -p1003.1-90 . 83.Sh HISTORY 84The 85.Fn umask 86function appeared in 87.At v7 . 88