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.\" @(#)umask.2 6.2 (Berkeley) 3/10/91 33.\" 34.Dd March 10, 1991 35.Dt UMASK 2 36.Os BSD 4 37.Sh NAME 38.Nm umask 39.Nd set file creation mode mask 40.Sh SYNOPSIS 41.Fd #include <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. The 9 low-order 50access permission 51bits of 52.Fa numask 53are used by system calls, including 54.Xr open 2 , 55.Xr mkdir 2 , 56and 57.Xr mkfifo 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 022 (write access for owner 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 72function is always successful. 73.Sh SEE ALSO 74.Xr chmod 2 , 75.Xr mknod 2 , 76.Xr open 2 77.Sh STANDARDS 78The 79.Fn umask 80function call is expected to 81conform to IEEE Std 1003.1-1988 82.Pq Dq Tn POSIX . 83