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()Stops the scheduling loop owned by this object.
• AsyncStop(const TCallBack &)Stops the scheduling loop owned by this object, specifying a callback.
• CActiveSchedulerWait()Default constructor.
• CanStopNow()constReports whether stopping will have immediate effect.
• IsStarted()constReports whether this CActiveSchedulerWait object is currently started.
• Start()Starts a new wait loop under the control of the current active scheduler.
• ~CActiveSchedulerWait()Ensures that the attached scheduler loop, and all nested loops, are stopped prio...

Inherited from CBase:

• Delete(CBase *)Deletes the specified object.
• Extension_(TUint,TAny *&,TAny *)Extension function
• operator new(TUint)Allocates the object from the heap and then initialises its contents to binary z...
• operator new(TUint,TAny *)Initialises the object to binary zeroes.
• operator new(TUint,TLeave)Allocates the object from the heap and then initialises its contents to binary z...
• operator new(TUint,TLeave,TUint)Allocates the object from the heap and then initialises its contents to binary z...
• operator new(TUint,TUint)Allocates the object from the heap and then initialises its contents to binary z...

See also:

• CActiveScheduler...

IMPORT_C CActiveSchedulerWait();

Description

Default constructor.

IMPORT_C ~CActiveSchedulerWait();

Description

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

See also:

• CActiveSchedulerWait::AsyncStop()Stops the scheduling loop owned by this object.

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 CActiveSchedulerWait::AsyncStop() function or the CActiveScheduler::Halt(TInt)const function. CActiveSchedulerWait::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.

See also:

• CActiveSchedulerWait::AsyncStop()Stops the scheduling loop owned by this object.
• CActiveSchedulerWait::IsStarted()constReports whether this CActiveSchedulerWait object is currently started.
• CActiveScheduler::Start()Starts a new wait loop under the control of the current active scheduler.
• CActiveScheduler::Halt(TInt)constUnilaterally terminates the current scheduler loop.

IMPORT_C void AsyncStop();

Description

Stops the scheduling loop owned by this object.

Note that the corresponding call to CActiveSchedulerWait::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 CActiveSchedulerWait::AsyncStop() provides a callback which is invoked immediately after the scheduler loop actually stops before the corresponding call to CActiveSchedulerWait::Start() returns.

Note that the corresponding call to CActiveSchedulerWait::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 CActiveSchedulerWait::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.

See also:

• CActiveSchedulerWait::Start()Starts a new wait loop under the control of the current active scheduler.
• CActiveSchedulerWait::AsyncStop()Stops the scheduling loop owned by this object.

IMPORT_C TBool CanStopNow() const;

Description

Reports whether stopping will have immediate effect.

This returns an indication of whether a call to CActiveSchedulerWait::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 CActiveSchedulerWait::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.

See also:

• CActiveSchedulerWait::Start()Starts a new wait loop under the control of the current active scheduler.
• CActiveSchedulerWait::AsyncStop()Stops the scheduling loop owned by this object.