This function is issued by a server application after receiving a WM_DDE_INITIATE message that identifies this server application (or indicates that any application can respond), and also either identifies a particular topic which the server can support, or asks for all supported topics (see WinDdeInitiate). This function sends a WM_DDE_INITIATEACK message back to the client, that is the sender of the WM_DDE_INITIATE message.

If the server application can respond, it issues this function once if a specific topic was requested, or once for each topic which it can support, if all supported topics were requested.

A DDE conversation is initiated each time this function is successfully issued. The client is expected to terminate all unwanted conversations. Once a conversation is initiated, it is controlled by the client issuing WinDdePostMsg functions.

To support DDE conversations between applications running in different memory models (16-bit and 32-bit) it is necessary to process all DDE messages in the application window procedure. The use of the WinDispatchMsg function ensures that conversion is performed on memory or segment addresses.