Lets recall how signals are handled by default:
- A process traps a signal n.
- Signal n is delivered to the process (either by another process or the OS).
- The signal handler is dispatched; that is, it runs in response to the signal.
- Signal n is now auto-masked; that is, blocked from delivery to the process.
- Signal handling is completed.
- Signal n is now auto-unmasked, that is, enabled for delivery to the process.
This is reasonable: while handling a particular signal, that signal is masked. This is the default behavior.
However, what if you are writing, say, an embedded real-time application, where the signal delivery implies some real-world event has occurred and the application must respond to this ...
