NAME
umask —
set file creation mode
mask
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#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 permission 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 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
chmod(2),
mkdir(2),
mkfifo(2),
mknod(2),
open(2)
STANDARDS
The
umask() function conforms to
IEEE Std
1003.1-1990 (“POSIX.1”).