set file creation mode mask
routine sets the process's file mode creation mask to
cmask and returns the previous value of the mask. The
9 low-order access permission bits of cmask are used
by system calls, including open(2), mkdir(2), mkfifo(2), and
turn off corresponding bits requested in file mode. (See
This clearing allows each user to restrict the default access to his
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.
The previous value of the file mode mask is returned by the call.
umask() function is always
The include file
chmod(2), mkdir(2), mkfifo(2), mknod(2), open(2), compat(5)
umask() function call is expected to
conform to IEEE Std 1003.1-1988