_ActivateHandler( ) API Library Routine Example

The following example activates an event handler when the library is loaded. The event handler prints a message for every event and lets Visual FoxPro process the event as it does normally. The event handler is deactivated when the library is unloaded.

Visual FoxPro Code

SET LIBRARY TO ACTIHAND
WAIT WINDOW TO m.test TIMEOUT 5
SET LIBRARY TO

C Code

#include <pro_ext.h>

static int HandlerID;

//   This is the routine that is registered as an event handler.
FAR EventHandler(WHandle theWindow, EventRec FAR *ev)
{
   _PutStr("\nEventHandler() called.");
   return NO;   // event still needs to be handled by Visual FoxPro
}

FAR Activate()
{
   HandlerID = _ActivateHandler(EventHandler);
}

//   When the library is unloaded we must deactivate the event handler
//   in a CALLONUNLOAD function.
FAR DeActivate()
{
   _DeActivateHandler(HandlerID);
}

FoxInfo myFoxInfo[] = {
   {"ACTIVATE",  Activate,   CALLONLOAD, ""},
   {"DEACTIVATE", DeActivate, CALLONUNLOAD, ""}
};
FoxTable _FoxTable = {
   (FoxTable FAR *) 0, sizeof(myFoxInfo)/sizeof(FoxInfo), myFoxInfo
};