Class CActiveSchedulerWait

class CActiveSchedulerWait : public CBase;

Description

Controls a single scheduling loop in the current active scheduler.

This class provides better control of nested wait loops in the active scheduler.

Note that a CActiveSchedulerWait object can be used as a data member inside other CBase derived classes.

Derivation

• CBase - Base class for all classes to be instantiated on the heap

• CActiveSchedulerWait - Controls a single scheduling loop in the current active scheduler

Members

Defined in CActiveSchedulerWait:
AsyncStop(), AsyncStop(), CActiveSchedulerWait(), CanStopNow(), IsStarted(), Start(), ~CActiveSchedulerWait()

Inherited from CBase:
Delete(), Extension_(), operator new()

See also:

• CActiveScheduler

IMPORT_C CActiveSchedulerWait();

Description

Defaulst constructor.

IMPORT_C ~CActiveSchedulerWait();

Description

Ensures that the attached scheduler loop, and all nested loops, are stopped prior to destruction.

See also:

• AsyncStop()

IMPORT_C void Start();

Description

Starts a new wait loop under the control of the current active scheduler.

Compared with CActiveScheduler::Start(), this object owns control of the scheduling loop that is started, and that loop can only be stopped by using this objects AsyncStop() function or the CActiveScheduler::Halt() function. Start() only returns when either of thos has occurred.

This is the preferred way to start a nested wait loop. Typically, a nested wait loop is used when the handling of a completed event in an active object requires processing further events from the other active objects before it can complete. This is a form of modal processing.

Panic codes

E32USER-CBase 44 if the thread does not have an active scheduler installed. E32USER-CBase 91 if this object has already been started.

IMPORT_C void AsyncStop();

Description

Stops the scheduling loop owned by this object.

Note that the corresponding call to Start() only returns once all nested scheduler loops have stopped.

Panic codes

E32USER-CBase 92 if the wait object has not been started.

IMPORT_C void AsyncStop(const TCallBack &aCallMeWhenStopped);

Description

Stops the scheduling loop owned by this object, specifying a callback.

This version of AsyncStop() provides a callback which is invoked immediately after the scheduler loop actually stops before the corresponding call to Start() returns.

Note that the corresponding call to Start() only returns once all nested scheduler loops have stopped.

Parameters

const TCallBack &aCallMeWhenStopped The callback to invoke when the scheduler loop exits.

Panic codes

E32USER-CBase 92 if the wait object has not been started.

inline TBool IsStarted() const;

Description

Reports whether this CActiveSchedulerWait object is currently started.

Note: a CActiveSchedulerWait object itself becomes "stopped" as soon as AsyncStop() is called, and can be started again immediately if required (but this would start a new nested level of the scheduler).

Return value

TBool True if the scheduling loop is active; false, otherwise.

IMPORT_C TBool CanStopNow() const;

Description

Reports whether stopping will have immediate effect.

This returns an indication of whether a call to AsyncStop() would be expected to stop the scheduler loop immediately, or whether it will have to wait until nested scheduler loops have stopped. This may alter which version of AsyncStop() you would want to call.

Return value

TBool Boolean indicating if the scheduling loop would stop immediately.

Panic codes

E32USER-CBase 92 if the wait object has not been started.