error C2664 : cannot convert parameter ( fingerprint sensor detection) - c++

Question

I'm having this error and I can't find how to solve this. Which parameter should i change? I am having this error.
error C2664: 'WinBioLocateSensorWithCallback' : cannot convert parameter 2 from 'void (__stdcall *)(void)' to 'PWINBIO_LOCATE_SENSOR_CALLBACK'
Thanks for your help guys!
Here is the code
#include <Windows.h>
#include <Conio.h>
#include <Stdio.h>
#include <WinBio.h>
VOID CALLBACK LocateSensorCallback();
HRESULT LocateSensorWithCallback(BOOL bCancel)
{
HRESULT hr = S_OK;
WINBIO_SESSION_HANDLE sessionHandle = NULL;
WINBIO_UNIT_ID unitId = 0;
// Connect to the system pool.
hr = WinBioOpenSession(
WINBIO_TYPE_FINGERPRINT, // Service provider
WINBIO_POOL_SYSTEM, // Pool type
WINBIO_FLAG_DEFAULT, // Configuration and access
NULL, // Array of biometric unit IDs
0, // Count of biometric unit IDs
NULL, // Database ID
&sessionHandle // [out] Session handle
);
if (FAILED(hr))
{
wprintf_s(L"\n WinBioOpenSession failed. hr = 0x%x\n", hr);
goto e_Exit;
}
wprintf_s(L"\n Calling WinBioLocateSensorWithCallback.");
hr = WinBioLocateSensorWithCallback(
sessionHandle, // Open biometric session
LocateSensorCallback, // Callback function
NULL // Optional context
);
if (FAILED(hr))
{
wprintf_s(L"\n WinBioLocateSensorWithCallback failed.");
wprintf_s(L"hr = 0x%x\n", hr);
goto e_Exit;
}
wprintf_s(L"\n Swipe the sensor ...\n");
// Cancel the identification if the bCancel flag is set.
if (bCancel)
{
wprintf_s(L"\n Starting CANCEL timer...\n");
Sleep( 7000 );
wprintf_s(L"\n Calling WinBioCancel\n");
hr = WinBioCancel( sessionHandle );
if (FAILED(hr))
{
wprintf_s(L"\n WinBioCancel failed. hr = 0x%x\n", hr);
goto e_Exit;
}
}
// Wait for the asynchronous identification process to complete
// or be canceled.
hr = WinBioWait( sessionHandle );
if (FAILED(hr))
{
wprintf_s(L"\n WinBioWait failed. hr = 0x%x\n", hr);
}
e_Exit:
if (sessionHandle != NULL)
{
wprintf_s(L"\n Closing the session.\n");
hr = WinBioCloseSession(sessionHandle);
if (FAILED(hr))
{
wprintf_s(L"\n WinBioCloseSession failed. hr = 0x%x\n", hr);
}
sessionHandle = NULL;
}
wprintf_s(L"\n Hit any key to exit...");
_getch();
return hr;
}
//------------------------------------------------------------------------
// The following function is the callback for
// WinBioLocateSensorWithCallback. The function filters the response
// from the biometric subsystem and writes a result to the console window.
//
VOID CALLBACK LocateSensorCallback(
__in_opt PVOID LocateCallbackContext,
__in HRESULT OperationStatus,
__in WINBIO_UNIT_ID UnitId
)
{
UNREFERENCED_PARAMETER(LocateCallbackContext);
wprintf_s(L"\n LocateSensorCallback executing.");
// A sensor could not be located.
if (FAILED(OperationStatus))
{
wprintf_s(L"\n LocateSensorCallback failed.");
wprintf_s(L"OperationStatus = 0x%x\n", OperationStatus);
}
// A sensor was located.
else
{
wprintf_s(L"\n Selected unit ID: %d\n", UnitId);
}
}
void main()
{
LocateSensorWithCallback(1);
}

Answer 1

Your problem is that your definition for LocateSensorCallback doesn't match the signature that the WinBioLocateSensorWithCallback function expects.
Change your forward declaration at the top from
VOID CALLBACK LocateSensorCallback();
to match the actual function:
VOID CALLBACK LocateSensorCallback(
__in_opt PVOID LocateCallbackContext,
__in HRESULT OperationStatus,
__in WINBIO_UNIT_ID UnitId
);