Signal Handling - nthallen/monarch GitHub Wiki

The DAS_IO::Loop::event_loop() uses pselect(3) in order to safely handle signals. The Loop maintains two signal masks: the blockset and the runset. The blockset blocks signals handled by the Loop, and the runset unblocks those same signals.

There are three key functions for setting up signals:

• DAS_IO::Loop::signal(signum, handler)
  • sets a signal handler with ::signal() and also updates the blockset and runset accordingly.
• DAS_IO::Interface::signal(signum, enable=true)
  • sets the given Interface to handle the specified signal serially. When the signal is received, the Interface's serialized_signal_handler() method will be called. The default implementation will simply exit the event_loop().
  • Must be called after the Interface has been added to a Loop, so the call could be logically placed within the Interface's adopted() method.
  • The optional second argument if set to false will disable the signal.
• DAS_IO::Server::signal(signum)
  • sets the Server to handle the specified signal, shutting the server down gracefully. If the server requires some other behavior, you should consider using DAS_IO::Interface::signal() instead.