Reply When Operation has been Completed

To design your application to be completely open, you want to notify the sending process that its requested operation has been performed. However, the operation invoked by a request sometimes takes a relatively long time to complete compared to the very brief time it takes to send the message. Since the sending process is expecting a reply, your tool can respond in two ways:

1. It can reply immediately that it has received the request and then convey the actual results of the completed operation in a later message.

2. It can withhold the reply until the operation has been completed.

   We recommend the second policy because ToolTalk messaging is entirely asynchronous: neither a tool (nor the session it is in) is blocked because it has one or more requests outstanding.