WM_DDE_POKE
A DDE client
application posts a WM_DDE_POKE message to a DDE server application. A client
uses this message to request the server to accept an unsolicited data item. The
server is expected to reply with a WM_DDE_ACK message indicating whether it accepted the data
item.
WM_DDE_POKE
wParam = (WPARAM) hwnd; // handle of posting application
lParam = (LPARAM) lPackedVal; // packed DDEPOKE and item atom
Parameters
hwnd
Value of wParam.
Identifies the client window posting the message.
lPackedVal
Value of lParam.
The component parameters that are packed into lPackedVal are extracted
by calling the UnpackDDElParam function. The low-order word is hData. The
high-order word is aItem.
|
Parameter |
Description |
|
hData |
Identifies
a global memory object containing a DDEPOKEKE_NJ2 structure with the data and additional
information. |
|
aItem |
Contains a
global atom that identifies the data item for which the data or notification
is being sent. |
Remarks
Posting
The client
application posts the WM_DDE_POKE message by using the PostMessage function.
The client
application must allocate memory for the hData object by using the GlobalAlloc function with the
GMEM_DDESHARE option. The client application must delete the hData
object if either of the following conditions is true:
The server application responds
with a negative WM_DDE_ACK
message.
The fRelease member is
FALSE, but the server application responds with either a positive or negative
WM_DDE_ACK.
The client
application must create the aItem atom by using the GlobalAddAtom function.
The client application
must create or reuse the WM_DDE_POKE lPackedVal parameter by calling the
PackDDElParam
function or the ReuseDDElParam function with hData supplied as the low-order
word and aItem supplied as the high-order word.
Receiving
The server
application should post the WM_DDE_ACK message to respond positively or
negatively. When posting WM_DDE_ACK, the server can either reuse the aItem
atom, or it can delete it and create a new one.
The server
must create or reuse the WM_DDE_ACK lPackedVal parameter by calling the PackDDElParam function or the ReuseDDElParam function with wStatus
supplied as the low-order word and aItem supplied as the high-order
word.
To free the hData
object, the server should call the GlobalFreeDVJHB. function. Also, if the data format is
either CF_DSPMETAFILEPICT or CF_METAFILEPICT, the server must also call DeleteMetaFile
with the embedded metafile handle. These two formats have an extra level of indirection;
that is, an application must lock hData to get a pointer to a handle,
then lock that handle to get a pointer to a METAFILEPICT structure, and
finally call DeleteMetaFile with the handle from the hMF member
of the METAFILEPICT structure.
To free the lPackedVal
object, the server should call the FreeDDElParam function.
See Also