DDE structure.
This points to a dynamic data exchange structure. See DDESTRUCT.
Flags in the fsStatus field are set as follows:
DDE_FACKREQ
If this bit is 1, the receiving (server)
application is requested to send its WM_DDE_DATA
messages with the acknowledgment-requested (DDE_FACKREQ) bit set. This
offers a flow control technique, whereby the client application can avoid
overload from incoming WM_DDE_DATA messages.
DDE_FNODATA
If this bit
is 1, the server is requested to send its WM_DDE_DATA
messages with a zero length data portion. These messages are alarms
that tell the client the source data has changed. Upon receiving one of
these alarms, the client can choose to call for the latest version of the
data by issuing a WM_DDE_REQUEST message,
or the client can choose to ignore the alarm. This is typically used when
there is a significant resource cost associated with actually rendering
and/or assimilating the data.
offszItemName identifies
which data item is being requested.
usFormat is the preferred type of data of the client. It must be
a registered DDE data format number.