Why the program crash after it call the function of DLL compiled by VC++

[bluevoice]

my main program is compiled by QT, and DLL is compiled by VC2005.

I has add a pushbutton on my dialog, then connect with the SLOT

@
connect(ui->btnOK,SIGNAL(clicked()),this, SLOT(onPressButton()));
@

and the detail of slot is

@
void MainWindow::onPressButton()
{
QLibrary lib("AvScanerDrv.dll");
if(!lib.load() || !lib.isLoaded())
{
QMessageBox::warning(this, tr("Warn"),tr("Can't load AvScanerDrv.dll !"));
return;
}

typedef int (*funGetCount)(void);
funGetCount GetScanerCount;
GetScanerCount = (funGetCount)lib.resolve("J_GetCount");
if(GetScanerCount!=NULL)
GetScanerCount();
QMessageBox::warning(this,tr("Test"),tr("Test this demo"));

}
@

My DLL is simple, the J_GetScanerCount function is :

@
extern "C" int PASCAL EXPORT J_GetCount(HWND hParent)
{
AFX_MANAGE_STATE(AfxGetStaticModuleState());
//HWND hParent ;
int nCount=0;
::MessageBox(NULL,_T("66"),_T("DLL"),MB_OK);
return nCount;
}
@

but the main program would crash after it has displayed the messagebox about ("66","DLL")

[EDIT: code formatting, please wrap in @-tags, Volker]

[Franzk]

[quote author="bluevoice" date="1306985636"]my main program is compiled by QT, and DLL is compiled by VC2005.[/quote]No, your main program is not compiled by Qt. Qt is a library, not a compiler.

I don't know what your program is crashing on though.

[cincirin]

From what I see, your funGetCount is declared @typedef int (*funGetCount)(void)@, and exported function from dll is declared @int PASCAL EXPORT J_GetCount(HWND hParent)@ Try to export function from dll as: @int PASCAL EXPORT J_GetCount()@