| class CMsvOperationWait : public CActive |
Utility class used to wait until an asynchronous messaging operation has completed.
Note that CMsvOperationActiveSchedulerWait is simpler to use, and should be used in preference to this class.
To use the class:
1. Create a new CMsvOperationWait object
2. Call the messaging function that returns the asynchronous operation. The operation observer parameter should be the iStatus word of the CMsvOperationWait object. This means that the CMsvOperationWait object will be signalled when the operation completes.
3. Call the CMsvOperationWait object's Start() function. This sets the object to be active.
4. Call CActiveScheduler::Start(). This starts a nested active scheduler. The program will then wait until this active scheduler is stopped. The CMsvOperationWait object stops the scheduler when the operation completes, allowing the program to continue.
These steps cause the program to wait until the operation completes.
CMsvOperationWait* waiter=CMsvOperationWait::NewLC();
CMsvOperation* op = function_returning_opLC(waiter->iStatus);
waiter->Start();
CActiveScheduler::Start();
CleanupStack::PopAndDestroy(2); // op, waiter
| Public Member Functions | |
|---|---|
| ~CMsvOperationWait() | |
| IMPORT_C CMsvOperationWait * | NewLC(TInt) |
| IMPORT_C void | Start() |
| Protected Member Functions | |
|---|---|
| CMsvOperationWait(TInt) | |
| void | DoCancel() |
| void | RunL() |
| Inherited Enumerations | |
|---|---|
| CActive:TPriority | |
| Inherited Attributes | |
|---|---|
| CActive::iStatus | |
| void | DoCancel | ( | ) | [protected, virtual] |
Implements cancellation of an outstanding request.
This function is called as part of the active object's Cancel().
It must call the appropriate cancel function offered by the active object's asynchronous service provider. The asynchronous service provider's cancel is expected to act immediately.
DoCancel() must not wait for event completion; this is handled by Cancel().
| IMPORT_C CMsvOperationWait * | NewLC | ( | TInt | aPriority = EPriorityStandard | ) | [static] |
| TInt aPriority = EPriorityStandard |
| void | RunL | ( | ) | [protected, virtual] |
Handles an active object's request completion event.
A derived class must provide an implementation to handle the completed request. If appropriate, it may issue another request.
The function is called by the active scheduler when a request completion event occurs, i.e. after the active scheduler's WaitForAnyRequest() function completes.
Before calling this active object's RunL() function, the active scheduler has:
1. decided that this is the highest priority active object with a completed request
2. marked this active object's request as complete (i.e. the request is no longer outstanding)
RunL() runs under a trap harness in the active scheduler. If it leaves, then the active scheduler calls RunError() to handle the leave.
Note that once the active scheduler's Start() function has been called, all user code is run under one of the program's active object's RunL() or RunError() functions.
CActiveScheduler::Start CActiveScheduler::Error CActiveScheduler::WaitForAnyRequest TRAPD
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