1.\" Copyright (c) 1980, 1991 Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)umask.2 6.2 (Berkeley) 03/10/91 7.\" 8.Dd 9.Dt UMASK 2 10.Os BSD 4 11.Sh NAME 12.Nm umask 13.Nd set file creation mode mask 14.Sh SYNOPSIS 15.Fd #include <sys/stat.h> 16.Ft mode_t 17.Fn umask "mode_t numask" 18.Sh DESCRIPTION 19The 20.Fn umask 21routine sets the process's file mode creation mask to 22.Fa numask 23and returns the previous value of the mask. The 9 low-order 24access permission 25bits of 26.Fa numask 27are used by system calls, including 28.Xr open 2 , 29.Xr mkdir 2 , 30and 31.Xr mkfifo 2 , 32to turn off corresponding bits 33requested in file mode. 34(see 35.Xr chmod 2 ) . 36This clearing allows each user to restrict the default access 37to his files. 38.Pp 39The default mask value is 022 (write access for owner only). 40Child processes inherit the mask of the calling process. 41.Sh RETURN VALUES 42The previous value of the file mode mask is returned by the call. 43.Sh ERRORS 44The 45.Fn umask 46function is always successful. 47.Sh SEE ALSO 48.Xr chmod 2 , 49.Xr mknod 2 , 50.Xr open 2 51.Sh STANDARDS 52The 53.Fn umask 54function call is expected to 55conform to IEEE Std 1003.1-1988 56.Pq Dq Tn POSIX . 57