_DeActivateHandler( ) 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 message. The event handler is deactivated when the library is unloaded. As in the following example, _DeActivateHandler( ) is usually called from a CALLONUNLOAD function.

Visual FoxPro Code

SET LIBRARY TO DEACTHAN

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