An application sends the WM_COPYDATA message to pass data to another application.
Syntax
To send this message, call the
SendMessage
function as follows.
lResult = SendMessage( // returns LRESULT in lResult
hWndControl, // (HWND) handle to destination control
WM_COPYDATA, // (UINT) message ID
wParam, // = () wParam;
lParam // = () lParam;
);
Parameters
- wParam
-
Handle to the window passing the data.
- lParam
-
Pointer to a COPYDATASTRUCT structure that contains the data to be passed.
Return Value
If the receiving application processes this message, it should return TRUE; otherwise, it should return FALSE.
Remarks
The data being passed must not contain pointers or other references to objects not accessible to the application receiving the data.
While this message is being sent, the referenced data must not be changed by another thread of the sending process.
The receiving application should consider the data read-only. The
lParam parameter is valid only during the processing of the message. The receiving application should not free the memory referenced by
lParam. If the receiving application must access the data after SendMessage returns, it must copy the data into a local buffer.
For an example, see Using Data Copy.
Message Information
| Header | Declared in Winuser.h, include Windows.h |
|---|
| Minimum operating systems |
Windows 95, Windows NT 3.1 |
|---|
See Also