UMASK(2) |
FreeBSD System Calls Manual |
UMASK(2) |
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), 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() system call is always successful.
STANDARDS
The
umask() system call is expected to conform to IEEE Std 1003.1-1990 (“POSIX.1”).
HISTORY
The
umask() function appeared in Version 7 AT&T UNIX.