An active object that performs processing that is only performed once.

The active object is intended to be given a low priority, so that it runs only when no higher-priority active objects are ready to run. In addition, the class ensures that the current thread cannot be closed until the active object is destroyed.

The class needs to be derived from to make use of its behaviour, in particular, it needs to define and implement a RunL() function.

NB: the constructor creates a process-relative handle to the current thread and this is stored within this object. If the thread subsequently dies abnormally, then this handle will not be closed, and the thread will not be destroyed until the process terminates.

NB: if Call() is called from a different thread (for example, to implement a kind of inter-thread communication), a client-specific mechanism must be used to ensure that the thread that created this object is still alive.

NB: if the thread that created this object has its own heap and terminates abnormally, then the handle stored within this object is lost.

CActive::RunL CAsyncOneShot::Call