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.Dd June 4, 1993 29.Dt UMASK 2 30.Os 31.Sh NAME 32.Nm umask 33.Nd set file creation mode mask 34.Sh LIBRARY 35.Lb libc 36.Sh SYNOPSIS 37.In sys/stat.h 38.Ft mode_t 39.Fn umask "mode_t numask" 40.Sh DESCRIPTION 41The 42.Fn umask 43routine sets the process's file mode creation mask to 44.Fa numask 45and returns the previous value of the mask. 46The 9 low-order 47access permission 48bits of 49.Fa numask 50are used by system calls, including 51.Xr open 2 , 52.Xr mkdir 2 , 53and 54.Xr mkfifo 2 , 55to turn off corresponding bits 56requested in file mode. 57(See 58.Xr chmod 2 ) . 59This clearing allows each user to restrict the default access 60to his files. 61.Pp 62The default mask value is S_IWGRP|S_IWOTH (022, write access for the 63owner only). 64Child processes inherit the mask of the calling process. 65.Sh RETURN VALUES 66The previous value of the file mode mask is returned by the call. 67.Sh ERRORS 68The 69.Fn umask 70system call is always successful. 71.Sh SEE ALSO 72.Xr chmod 2 , 73.Xr mkfifo 2 , 74.Xr mknod 2 , 75.Xr open 2 76.Sh STANDARDS 77The 78.Fn umask 79system call is expected to conform to 80.St -p1003.1-90 . 81.Sh HISTORY 82The 83.Fn umask 84function appeared in 85.At v7 . 86