Using WM_COPYDATA for IPC

The WM_COPYDATA message enables you to send data from one application to another. The receiving application gets the data in a COPYDATASTRUCT structure. When data is being passed between a 16-bit Windows-based application and a Win32-based application, the system translates any pointers.

For example code, see the following Platform SDK samples:

• SPY. This sample, located in MSTOOLS\SAMPLES\SDKTOOLS\SPY, uses WM_COPYDATA to pass data to another application.
• INTEROP. This sample, located in SCT\SAMPLES, uses WM_COPYDATA to dispatch calls from a 16-bit Windows-based application to a Win32-based DLL.