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Date Posted: 10:59:05 02/19/03 Wed
Author: Sergey Muschin
Subject: How to declare OnAcquireEvent function in BCB

here is what i'm trying to do

//declaration
public: // User declarations
TAcquireEvent OnAcquireEvent;

//implementation
void __fastcall OnAcquireEvent(const unsigned DibHandle, const Word XDpi, const Word YDpi, const int CallBackData)
{
TTiffGraphic* tif = new TTiffGraphic();
tif->AssignFromDIBHandle(DibHandle);
tif->XDotsPerInch = XDpi;
tif->YDotsPerInch = YDpi;
tif->SaveToFile("snm.tif");
delete tif;
}

//how do i call it
Scanner()->Acquire(OnAcquireEvent,0);

And as result i'm getting EAccessViolation exception.
When i look at

procedure GetAllImages( var Msg : TMsg;
var TwainQuit : Boolean;
const AcquireEvent : TAcquireEvent;
const pSourceId : pTW_IDENTITY;
const pAppId : pTW_IDENTITY;
const DsmEntry : TDSM_Entry;
const CallBackData : LongInt );

in debuger i can see that AcquireEvent is null.
So what i'm doing wrong?

Regards,
Sergey Muschin

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