getSignalMask calls sigprocmask to determine the set of interrupts which are currently being blocked.
setFileCreationMask mode sets the file mode creation mask to mode. Modes set by this operation are subtracted from files and directories upon creation. The previous file creation mask is returned.
Note: calls umask.
setSignalMask mask calls sigprocmask with SIG_SETMASK to block all interrupts in mask.