EMA C++ RDM Usage Guide : 6 Market Price Domain : 6.4 Special Semantics
 
6.4 Special Semantics
6.4.1 Snapshots
MarketPrice is one of a few message model types that support a true snapshot. If a non-streaming request is made, then the UpdateMsg will not be sent. Status messages could be received before the single Refresh response message (for details refer to Section 2.3) is received. For streaming and snapshot streams, the Refresh response message will always be a single message and it will have RefreshMsg.Complete is set to true.