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Registering for Sub-Connection events: Tutorial

This tutorial describes how an application can register for sub-connection events.

This tutorial has three parts. The first part describes how the application can register for all events. The second part describes how the application can register for a subset of events. The third part describes how the application can extract information from an event response.

Registering for events – Simple case

The following example shows the simplest case of how an application can register for events occurring on a sub-connection. In this example the application registers for notification of all events.

       
        
       
       // Create the container for all sub connection parameters
RSubConParameterBundle subconParams;
CleanupClosePushL(subconParams);

………
………
// Create and initialise parameters sets as above
………
………

// Create a new sub-connection
subconn.Open(ss, RSubConnection::ECreateNew, conn);

TNotificationEventBuf eventBuffer;
TRequestStatus eventStatus;
subconn.EventNotification(eventBuffer, EFalse, eventStatus);

// Set Properties of the sub-connection
subconn.SetParameters(subconParams);

// Destroy parameters
CleanupStack::PopAndDestroy();         // subconParams

// Open and connect a TCP socket on the sub-connection
sock.Open(ss, KAfInet, KSockStream, KProtocolInetTcp, subconn);
sock.Connect(destAddr, status);
User::WaitForRequest(status);

// Negotiation may not occur until a socket is assigned to the sub-connection
// First event should be cSubConGenEventDataClientJoining
User::WaitForRequest(eventStatus);

// Next we’d expect a CSubconGenEventParamsGranted/ CSubconGenEventParamsRejected
subconn.EventNotification(eventBuffer, EFalse, eventStatus);
User::WaitForRequest(eventStatus);

Note: Error handling is not included to aid clarity.

Registering for events – Using filters

The following example shows how to register for specific events by using filters. In this example the application registers for notification when sub-connection parameters have been granted or rejected. Each TEventFilter contains the factory Uid of the events and a mask of event Ids bitwise OR’d together.

       
        
       
       // Create the container for all sub connection parameters
RSubConParameterBundle subconParams;
CleanupClosePushL(subconParams);

………
………
// Create and initialise parameters sets as above
………
………

// Create a new sub-connection
subconn.Open(ss, RSubConnection::ECreateNew, conn);

// Create event filter
TEventFilter filter;
filter.iEventGroupUid = KSubConnGenericEventsImplUid;
filter.iEventMask = KSubConGenericEventParamsRejected | KSubConGenericEventParamsGranted;

// Register for event
TNotificationEventBuf eventBuffer;
TRequestStatus eventStatus;
subconn.EventNotification(eventBuffer, &filter, 1, eventStatus);

// Set Properties of the sub-connection
subconn.SetParameters(subconParams);

// Destroy parameters
CleanupStack::PopAndDestroy();         // subconParams

// Open and connect a TCP socket on the sub-connection
sock.Open(ss, KAfInet, KSockStream, KProtocolInetTcp, subconn);
sock.Connect(destAddr, status);
User::WaitForRequest(status);

// Event should be CSubconGenEventParamsGranted/CSubconGenEventParamsRejected
User::WaitForRequest(eventStatus);

Note: Error handling is not included to aid clarity.

Extracting information from received events

The following example shows how to extract the information contained within an event notification once it has been received.

       
        
       
       // Create the container for all sub connection parameters
RSubConParameterBundle subconParams;
CleanupClosePushL(subconParams);

………
………
// Create and initialise parameters sets as above
………
………

// Create a new sub-connection
subconn.Open(ss, RSubConnection::ECreateNew, conn);

// Create filter, register for events, and set parameters as above
……
subconn.EventNotification(eventBuffer, &filter, 1, eventStatus);
……

// Open and connect a TCP socket on the sub-connection
……

// Receive the event notification
User::WaitForRequest(eventStatus);

CSubConNotificationEvent* event;
event = CSubConNotificationEvent::NewL(eventBuffer);
CleanupStack::PushL (event);

if (event->GroupId() == KSubConnGenericEventsImplUid
    && event->Id() == CSubConGenEventParamsRejected)
    {
    CSubConGenEventParamsRejected* rejectedEvent =
        static_cast< CSubConGenEventParamsRejected*>(event);

    TInt error = rejectedEvent->Error();
    ……
    // Do something with the error
    ……
    }

CleanupStack::PopAndDestroy (event);

Note: Error handling is not included to aid clarity.

Parent topic: Socket Server Tutorials