These fields in the ECI parameter block are to support environment-dependent extensions.
The handle of the window to which the reply message will be posted.
The ECI uses this field as input only.
Windows applications should pass an event object handle.
The ECI uses this field as input only.
The handle of the Windows window to which the reply message will be posted.
The ECI uses this field as input only.
The Windows hInstance of the calling program as supplied during program initialization.
The ECI uses this field as input only.
The handle of the window that is to be disabled during the synchronous call.
The ECI uses this field as input only.
The message identifier to be used for posting the reply message to the window specified in the relevant window handle.
The ECI uses this field as input only.