Invoked in:
Server
Message from Partner:
WM_DDE_REQUEST
Remarks:
This event is invoked in a server as notification that a client is requesting data. The server should get the item name (DDEGetItemName) and the format (DDEGetFormat) to determine if it can honor the request for this item in this format.
Required Response:
Upon receipt of a request for data, the DDE protocol requires that the server respond as follows. The server must respond to this event before attempting to transmit another event to the partner.
Acknowledgment |
Subroutine Called |
Message |
Positive (Request can be honored) |
WM_DDE_DATA |
|
Negative (Request cannot be honored) |
DDEAck with DDE_FACK status flag not set |
WM_DDE_ACK with DDE_FACK status bit cleared |
Default Processing
The DDE DLL default processing is to send a negative acknowledgment if the ESL program does not send any acknowledgment.
Available Queries:
Example:
response to stimulus DDE DDE_REQUEST
copy eventparam to ConvID_IV
copy DDEGetItemName (ConvID_IV) to ItemName_SV
copy DDEGetFormat (ConvID_IV) to Format_SV
call GetTheData (ItemName_SV, Format_SV, DataString_SV, DidOK_BV)
if (DidOK_BV) then
copy (length of DataString_SV) to DataLength_IV
copy DDESetStatusFlag (0, DDE_FACKREQ) to Status_IV
copy DDESetStatusFlag (Status_IV, DDE_FRESPONSE) to Status_IV
call DDEDataString (ConvID_IV, ItemName_SV, DataString_SV, DataLength_IV, Format_SV, Status_IV)
else
copy 0 to Status_IV # send a negative ACK
call DDEAck (ConvID_IV, ItemName_SV, Format_SV, Status_IV)
end if
