How +to start active objects

diff -r 43e37759235e -r 51a74ef9ed63 Symbian3/SDK/Source/GUID-56841E07-1A4A-5572-BF3F-F80069FD5D59.dita --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/Symbian3/SDK/Source/GUID-56841E07-1A4A-5572-BF3F-F80069FD5D59.dita Wed Mar 31 11:11:55 2010 +0100 @@ -0,0 +1,66 @@ + + + + + +How +to start active objectsThis document describes how to start active objects. +

The following example code shows how active objects are started. While +the example shows the creation of an active scheduler, in UI applications, +an active scheduler is always provided.

Create an instance of +the active scheduler, exampleScheduler. This is an instance +of a class derived from CActiveScheduler and provides an Error() function +to handle leaves occurring in the active object RunL() function(s).
Push exampleScheduler onto +the cleanup stack and install as the current active scheduler.
Create an active object, myActiveObject, +and pass a pointer to the service provider as the parameter. Note that often, +the service provider may be constructed as part of the active object's own +construction processing.
Issue a request using IssueRequest().
Use CActiveScheduler::Start() to +start the active scheduler’s wait loop. At least one outstanding request is +necessary before the wait loop is started, otherwise the thread hangs. All +further request issuing and servicing occurs within this function. The wait +loop continues until one of the active objects’ RunL() requests +termination using CActiveScheduler::Stop().
Pop the active object, +the active scheduler and the example service provider from the clean-up stack, +and destroy. The code assumes that the active object does not take ownership +of the CExampleServiceProvider object and is not responsible +for its destruction.

+LOCAL_C void doExampleL() + { + // Create and install the active scheduler + CActiveScheduler* exampleScheduler=new (ELeave) CExampleScheduler; + CleanupStack::PushL(exampleScheduler); + CActiveScheduler::Install(exampleScheduler); + + // Create the service provider. Often, the + // service provider is part of the active object + CExampleServiceProvider* myServiceProvider=new (ELeave) CExampleServiceProvider; + CleanupStack::PushL(myServiceProvider); + + // Create the active object and issue the + // first asynchronous request + CExampleActiveObject * myActiveObject=new (ELeave) CExampleActiveObject(myServiceProvider); + CleanupStack::PushL(myActiveObject); + myActiveObject->IssueRequest(); + + // Now we can start the active scheduler + CActiveScheduler::Start(); + + // Remove the exampleScheduler and other + // objects from cleanup stack and destroy them + CleanupStack::PopAndDestroy(3); + } + \ No newline at end of file