WinBioVerifyWithCallback function (winbio.h)
Asynchronously captures a biometric sample and determines whether the sample corresponds to the specified user identity. The function returns immediately to the caller, performs capture and verification on a separate thread, and calls into an application-defined callback function to update operation status.
We recommend that, beginning with Windows 8, you no longer use this function to start an asynchronous operation. Instead, do the following:
- Implement a PWINBIO_ASYNC_COMPLETION_CALLBACK function to receive notice when the operation completes.
- Call the WinBioAsyncOpenSession function. Pass the address of your callback in the CallbackRoutine parameter. Pass WINBIO_ASYNC_NOTIFY_CALLBACK in the NotificationMethod parameter. Retrieve an asynchronous session handle.
- Use the asynchronous session handle to call WinBioVerify. When the operation finishes, the Windows Biometric Framework will allocate and initialize a WINBIO_ASYNC_RESULT structure with the results and invoke your callback with a pointer to the results structure.
- Call WinBioFree from your callback implementation to release the WINBIO_ASYNC_RESULT structure after you have finished using it.
Syntax
HRESULT WinBioVerifyWithCallback(
[in] WINBIO_SESSION_HANDLE SessionHandle,
[in] WINBIO_IDENTITY *Identity,
[in] WINBIO_BIOMETRIC_SUBTYPE SubFactor,
[in] PWINBIO_VERIFY_CALLBACK VerifyCallback,
[in, optional] PVOID VerifyCallbackContext
);
Parameters
[in] SessionHandle
A WINBIO_SESSION_HANDLE value that identifies an open biometric session.
[in] Identity
Pointer to a WINBIO_IDENTITY structure that contains the GUID or SID of the user providing the biometric sample.
[in] SubFactor
A WINBIO_BIOMETRIC_SUBTYPE value that specifies the sub-factor associated with the biometric sample. See the Remarks section for more details.
[in] VerifyCallback
Address of a callback function that will be called by the WinBioVerifyWithCallback function when verification succeeds or fails. You must create the callback.
[in, optional] VerifyCallbackContext
An optional application-defined structure that is returned in the VerifyCallbackContext parameter of the callback function. This structure can contain any data that the custom callback function is designed to handle.
Return value
If the function succeeds, it returns S_OK. If the function fails, it returns an HRESULT value that indicates the error. Possible values include, but are not limited to, those in the following table. For a list of common error codes, see Common HRESULT Values.
| Return code | Description |
|---|---|
|
The session handle is not valid. |
|
The SubFactor argument is incorrect. |
|
The pointer specified by the Identity and VerifyCallback parameters cannot be NULL. |
Remarks
The SubFactor parameter specifies the sub-factor associated with the biometric sample. The Windows Biometric Framework (WBF) currently supports only fingerprint capture and uses the following constants to represent sub-type information.
- WINBIO_ANSI_381_POS_RH_THUMB
- WINBIO_ANSI_381_POS_RH_INDEX_FINGER
- WINBIO_ANSI_381_POS_RH_MIDDLE_FINGER
- WINBIO_ANSI_381_POS_RH_RING_FINGER
- WINBIO_ANSI_381_POS_RH_LITTLE_FINGER
- WINBIO_ANSI_381_POS_LH_THUMB
- WINBIO_ANSI_381_POS_LH_INDEX_FINGER
- WINBIO_ANSI_381_POS_LH_MIDDLE_FINGER
- WINBIO_ANSI_381_POS_LH_RING_FINGER
- WINBIO_ANSI_381_POS_LH_LITTLE_FINGER
- WINBIO_ANSI_381_POS_RH_FOUR_FINGERS
- WINBIO_ANSI_381_POS_LH_FOUR_FINGERS
The WinBioVerifyWithCallback function returns immediately and passes S_OK to the caller. To determine the status of the capture and verification process, you must examine the OperationStatus parameter in your callback function.
You can call the WinBioCancel function to cancel a pending callback operation. Closing a session also implicitly cancels callbacks for that session.
The callback routine must have the following signature:
VOID CALLBACK VerifyCallback(
__in_opt PVOID VerifyCallbackContext,
__in HRESULT OperationStatus,
__in WINBIO_UNIT_ID UnitId,
__in BOOLEAN Match,
__in WINBIO_REJECT_DETAIL RejectDetail
);
Examples
The following function calls WinBioVerifyWithCallback to asynchronously determine whether a biometric sample matches the logged on identity of the current user. The callback routine, VerifyCallback, and a helper function, GetCurrentUserIdentity, are also included. Link to the Winbio.lib static library and include the following header files:
- Windows.h
- Stdio.h
- Conio.h
- Winbio.h
HRESULT VerifyWithCallback(BOOL bCancel, WINBIO_BIOMETRIC_SUBTYPE subFactor)
{
// Declare variables.
HRESULT hr = S_OK;
WINBIO_SESSION_HANDLE sessionHandle = NULL;
WINBIO_UNIT_ID unitId = 0;
WINBIO_REJECT_DETAIL rejectDetail = 0;
WINBIO_IDENTITY identity = {0};
// Find the identity of the user.
hr = GetCurrentUserIdentity( &identity );
if (FAILED(hr))
{
wprintf_s(L"\n User identity not found. hr = 0x%x\n", hr);
goto e_Exit;
}
// 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;
}
// Verify a biometric sample asynchronously.
wprintf_s(L"\n Calling WinBioVerifyWithCallback.\n");
hr = WinBioVerifyWithCallback(
sessionHandle, // Open session handle
&identity, // User SID or GUID
subFactor, // Sample sub-factor
VerifyCallback, // Callback function
NULL // Optional context
);
if (FAILED(hr))
{
wprintf_s(L"\n WinBioVerifyWithCallback failed. 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)
{
WinBioCloseSession(sessionHandle);
sessionHandle = NULL;
}
wprintf_s(L"\n Hit any key to continue...");
_getch();
return hr;
}
//------------------------------------------------------------------------
// The following function is the callback for WinBioVerifyWithCallback.
// The function filters the response from the biometric subsystem and
// writes a result to the console window.
//
VOID CALLBACK VerifyCallback(
__in_opt PVOID VerifyCallbackContext,
__in HRESULT OperationStatus,
__in WINBIO_UNIT_ID UnitId,
__in BOOLEAN Match,
__in WINBIO_REJECT_DETAIL RejectDetail
)
{
UNREFERENCED_PARAMETER(VerifyCallbackContext);
UNREFERENCED_PARAMETER(Match);
wprintf_s(L"\n VerifyCallback executing");
wprintf_s(L"\n Swipe processed for unit ID %d\n", UnitId);
// The identity could not be verified.
if (FAILED(OperationStatus))
{
wprintf_s(L"\n Verification failed for the following reason:");
if (OperationStatus == WINBIO_E_NO_MATCH)
{
wprintf_s(L"\n No match.\n");
}
else if (OperationStatus == WINBIO_E_BAD_CAPTURE)
{
wprintf_s(L"\n Bad capture.\n ");
wprintf_s(L"\n Bad capture; reason: %d\n", RejectDetail);
}
else
{
wprintf_s(L"VerifyCallback failed.");
wprintf_s(L"OperationStatus = 0x%x\n", OperationStatus);
}
goto e_Exit;
}
// The user identity was verified.
wprintf_s(L"\n Fingerprint verified:\n");
e_Exit:
return;
}
//------------------------------------------------------------------------
// The following function retrieves the identity of the current user.
// This is a helper function and is not part of the Windows Biometric
// Framework API.
//
HRESULT GetCurrentUserIdentity(__inout PWINBIO_IDENTITY Identity)
{
// Declare variables.
HRESULT hr = S_OK;
HANDLE tokenHandle = NULL;
DWORD bytesReturned = 0;
struct{
TOKEN_USER tokenUser;
BYTE buffer[SECURITY_MAX_SID_SIZE];
} tokenInfoBuffer;
// Zero the input identity and specify the type.
ZeroMemory( Identity, sizeof(WINBIO_IDENTITY));
Identity->Type = WINBIO_ID_TYPE_NULL;
// Open the access token associated with the
// current process
if (!OpenProcessToken(
GetCurrentProcess(), // Process handle
TOKEN_READ, // Read access only
&tokenHandle)) // Access token handle
{
DWORD win32Status = GetLastError();
wprintf_s(L"Cannot open token handle: %d\n", win32Status);
hr = HRESULT_FROM_WIN32(win32Status);
goto e_Exit;
}
// Zero the tokenInfoBuffer structure.
ZeroMemory(&tokenInfoBuffer, sizeof(tokenInfoBuffer));
// Retrieve information about the access token. In this case,
// retrieve a SID.
if (!GetTokenInformation(
tokenHandle, // Access token handle
TokenUser, // User for the token
&tokenInfoBuffer.tokenUser, // Buffer to fill
sizeof(tokenInfoBuffer), // Size of the buffer
&bytesReturned)) // Size needed
{
DWORD win32Status = GetLastError();
wprintf_s(L"Cannot query token information: %d\n", win32Status);
hr = HRESULT_FROM_WIN32(win32Status);
goto e_Exit;
}
// Copy the SID from the tokenInfoBuffer structure to the
// WINBIO_IDENTITY structure.
CopySid(
SECURITY_MAX_SID_SIZE,
Identity->Value.AccountSid.Data,
tokenInfoBuffer.tokenUser.User.Sid
);
// Specify the size of the SID and assign WINBIO_ID_TYPE_SID
// to the type member of the WINBIO_IDENTITY structure.
Identity->Value.AccountSid.Size = GetLengthSid(tokenInfoBuffer.tokenUser.User.Sid);
Identity->Type = WINBIO_ID_TYPE_SID;
e_Exit:
if (tokenHandle != NULL)
{
CloseHandle(tokenHandle);
}
return hr;
}
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 7 [desktop apps only] |
| Minimum supported server | Windows Server 2008 R2 [desktop apps only] |
| Target Platform | Windows |
| Header | winbio.h (include Winbio.h) |
| Library | Winbio.lib |
| DLL | Winbio.dll |
See also
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