EMA C++ Developers Guide : 5 Provider Classes : 5.1 OmmProvider Class : 5.1.10 Working with Items
 
5.1.10 Working with Items
The application assigns unique numeric identifiers, called handles (e.g., UInt64) to all open items it is providing. Application must pass this identifier along with an item message on the call to submit(). The handles are used to manage item stream ids. To reassign a handle to a different item, application must first close the item previously associated with the given handle.