UMASK(2) OpenBSD Programmer's Manual UMASK(2)
NAME
umask - set file creation mode mask
SYNOPSIS
#include <sys/types.h>
#include <sys/stat.h>
mode_t
umask(mode_t numask);
DESCRIPTION
The umask() routine sets the process's file mode creation mask to numask
and returns the previous value of the mask. The 9 low-order access per-
mission bits of numask are used by system calls, including open(2),
mkdir(2), mkfifo(2) and mknod(2) to turn off corresponding bits requested
in file mode. (See chmod(2)). This clearing allows each user to restrict
the default access to his files.
The default mask value is S_IWGRP|S_IWOTH (022, write access for the own-
er only). Child processes inherit the mask of the calling process.
RETURN VALUES
The previous value of the file mode mask is returned by the call.
ERRORS
The umask() function is always successful.
SEE ALSO
chmod(2), mkdir(2), mkfifo(2), mknod(2), open(2)
STANDARDS
The umask() function call is expected to conform to IEEE Std1003.1-1988
(``POSIX'').
OpenBSD 2.7 June 4, 1993 1