Chapter 1

{
return NULL; // Give up!
}
If the state entry completes successfully, however, the following code will be invoked by the
RunL():
CGdpStateMachine::TState* CGdpSmsSender::TSendMsgState::CompleteL()
{
RDebug::Print(_L("Message sent!!"));
delete iSender.iSmsMsg;
iSender.iSocket.Close();
// Let handler know message sent successfully
iSender.iHandler->SendComplete(KErrNone);
return NULL; // Last state so return NULL
}
This simply releases the resources we have used to send the message and notifies the
handler that we have successfully sent the message. Notice how we specify the next state to
enter as NULL as we have completed the process.
If the send fails, the ErrorL() function is invoked:
CGdpStateMachine::TState* CGdpSmsSender::TSendMsgState::ErrorL(TInt
aCode)
{
// Let handler know the reason for sent failure
iSender.iHandler->SendComplete(aCode);
User::Leave(aCode);
return NULL; // Never actually hit
}
The sender state machine's error handler performs the following:
CGdpStateMachine::TState* CGdpSmsSender::ErrorOnStateExit(TInt
/*aError*/)
{
Reset();
if (--iRetries < 0)
return NULL;
return CurrentState(); // Force re-entry to initial state
}
As asynchronous errors often indicate a communications error, we attempt to reset the state
machine and do a limited number of retries.