| class CIdle : public CActive |
An active object that performs low-priority processing when no higher-priority active objects are ready to run.
An idle time active object together with its associated callback function may be used to implement potentially long running background tasks, such as spreadsheet recalculation and word processor repagination.
| Public Member Functions | |
|---|---|
| ~CIdle () | |
| IMPORT_C CIdle * | New ( TInt ) |
| IMPORT_C CIdle * | NewL ( TInt ) |
| IMPORT_C void | Start ( TCallBack ) |
| Protected Member Functions | |
|---|---|
| CIdle ( TInt ) | |
| IMPORT_C void | DoCancel () |
| IMPORT_C void | RunL () |
| Inherited Enumerations | |
|---|---|
| CActive:TPriority | |
| Protected Attributes | |
|---|---|
| TCallBack | iCallBack |
| Inherited Attributes | |
|---|---|
| CActive::iStatus | |
| IMPORT_C | CIdle | ( | TInt | aPriority | ) | [protected] |
Protected constructor taking a priority value.
Sets this active object's priority value.
| TInt aPriority | The active object priority value. |
| IMPORT_C | ~CIdle | ( | ) |
Frees resources prior to destruction.
Specifically, it cancels any outstanding request.
| IMPORT_C void | DoCancel | ( | ) | [protected, virtual] |
Implements the cancellation of an outstanding request.
This function is called by the active object's Cancel() function.
| IMPORT_C CIdle * | New | ( | TInt | aPriority | ) | [static] |
Allocates and initialises an Idle time active object and adds it to the active scheduler.
| TInt aPriority | An integer specifying the priority of this active object. It must be lower than that of all other active objects on the active scheduler. The value CActive::TPriority::EPriorityIdle is recommended. |
| IMPORT_C CIdle * | NewL | ( | TInt | aPriority | ) | [static] |
Allocates and initialises an Idle time active object, adds it to the active scheduler, but leaves on failure.
| TInt aPriority | An integer specifying the priority of this active object. It must be lower than that of all other active objects on the active scheduler. The value CActive::TPriority::EPriorityIdle is recommended. |
| IMPORT_C void | RunL | ( | ) | [protected, virtual] |
Handles this idle active object's request completion event.
It is called when nothing of a higher priority can be scheduled.
| IMPORT_C void | Start | ( | TCallBack | aCallBack | ) |
Starts the background task.
The background task is encapsulated in the callback. The function represented by this callback is called every time this Idle time active object is scheduled to run.
The callback function should be structured to perform a background task in many increments, i.e. it should voluntarily relinquish control (i.e. return) after a suitable time interval to allow other, higher priority events to be handled.
If the callback function has further work to do, it should return a true value. This ensures that the active object is scheduled to run again later.
Once the callback function has finally completed its work, it should return a false value. The active object is then no longer scheduled to run.
| TCallBack aCallBack | A callback object encapsulating a function which is called when no higher priority active object is ready to run. |
| TCallBack | iCallBack | [protected] |
The callback object that encapsulates the background task.
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