RTEMS Ada User's Guide
The signal manager allows a task to optionally define an asynchronous signal routine (ASR). An ASR is to a task what an ISR is to an application's set of tasks. When the processor is interrupted, the execution of an application is also interrupted and an ISR is given control. Similarly, when a signal is sent to a task, that task's execution path will be "interrupted" by the ASR. Sending a signal to a task has no effect on the receiving task's current execution state.
A signal flag is used by a task (or ISR) to inform
another task of the occurrence of a significant situation.
Thirty-two signal flags are associated with each task. A
collection of one or more signals is referred to as a signal
set. The data type rtems.signal_set
is used to manipulate signal sets.
A signal set is posted when it is directed (or sent) to a task. A pending signal is a signal that has been sent to a task with a valid ASR, but has not been processed by that task's ASR.
RTEMS Ada User's Guide
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