The pcntl_sigprocmask function adds, removes or sets blocked signals, depending on the mode parameter.
Sets the behavior of pcntl_sigprocmask. Possible values: SIG_BLOCK: Add the signals to the currently blocked signals. SIG_UNBLOCK: Remove the signals from the currently blocked signals. SIG_SETMASK: Replace the currently blocked signals by the given list of signals.
List of signals.
The old_signals parameter is set to an array containing the list of the previously blocked signals.
Returns true on success or false on failure.