Signal generation and delivery

A signal is said to be generated when its occurrence is enqueued, to list of pending signals in the task structure of the receiver process or processes. The signal is generated (on a process or a group) upon request from a user-mode process, kernel, or any of the kernel services. A signal is considered to be delivered when the receiver process or processes are made aware of its occurrence and are forced to execute the appropriate response handler; in other words, signal delivery is equal to initialization of the corresponding handler. Ideally, every signal generated is assumed to be instantly delivered; however, there is a possibility of delay between signal generation, and it eventual delivery. To facilitate possible deferred delivery, the kernel provides separate functions for signal generation and delivery.

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