The CPL_INIT message is sent to the CPlApplet function of a Control Panel application to prompt it to perform global initialization, especially memory allocation.
CPL_INIT
This function has no parameters.
If initialization succeeds, the CPlApplet function should return a nonzero value. Otherwise, it should return zero. If CPlApplet returns zero, the controlling application ends communication and releases the DLL containing the Control Panel application.
Because this is the only way a Control Panel application can signal an error condition, the application should allocate memory in response to this message.
This message is sent immediately after the DLL containing the application is loaded.