NAME
umask —
set file creation mode mask
LIBRARY
library “libc”
SYNOPSIS
#include
<sys/stat.h>
mode_t
umask(mode_t
numask);
DESCRIPTION
Theumask()
routine sets the process's file mode creation mask to
numask and returns the previous value of the mask. The 9
low-order access permission bits of numask are used by
system calls, including
open(2),
mkdir(2), and
mkfifo(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 owner 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
STANDARDS
The umask() function call is expected to
conform to IEEE Std 1003.1-1990
(“POSIX.1”).
HISTORY
An umask() function call appeared in
Version 7 AT&T UNIX.