WinBioIdentify function

Captures a biometric sample and determines whether it matches an existing biometric template.

Syntax


HRESULT WINAPI WinBioIdentify(
  _In_       WINBIO_SESSION_HANDLE SessionHandle,
  _Out_opt_  WINBIO_UNIT_ID *UnitId,
  _Out_opt_  WINBIO_IDENTITY *Identity,
  _Out_opt_  WINBIO_BIOMETRIC_SUBTYPE *SubFactor,
  _Out_opt_  WINBIO_REJECT_DETAIL *RejectDetail
);

Parameters

SessionHandle [in]

A WINBIO_SESSION_HANDLE value that identifies an open biometric session. Open a synchronous session handle by calling WinBioOpenSession. Open an asynchronous session handle by calling WinBioAsyncOpenSession.

UnitId [out, optional]

A pointer to a ULONG value that specifies the biometric unit used to perform the identification.

Identity [out, optional]

Pointer to a WINBIO_IDENTITY structure that receives the GUID or SID of the user providing the biometric sample.

SubFactor [out, optional]

Pointer to a WINBIO_BIOMETRIC_SUBTYPE value that receives the sub-factor associated with the biometric sample. See the Remarks section for more details.

RejectDetail [out, optional]

A pointer to a ULONG value that contains additional information about the failure, if any, to capture a biometric sample. If the capture succeeded, this parameter is set to zero. The following values are defined for fingerprint capture:

  • WINBIO_FP_TOO_HIGH
  • WINBIO_FP_TOO_LOW
  • WINBIO_FP_TOO_LEFT
  • WINBIO_FP_TOO_RIGHT
  • WINBIO_FP_TOO_FAST
  • WINBIO_FP_TOO_SLOW
  • WINBIO_FP_POOR_QUALITY
  • WINBIO_FP_TOO_SKEWED
  • WINBIO_FP_TOO_SHORT
  • WINBIO_FP_MERGE_FAILURE

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 codeDescription
E_HANDLE

The session handle is not valid.

E_POINTER

The pointer specified by the UnitId, Identity, SubFactor, or RejectDetail parameters cannot be NULL.

WINBIO_E_BAD_CAPTURE

The sample could not be captured. Use the RejectDetail value for more information.

WINBIO_E_ENROLLMENT_IN_PROGRESS

The operation could not be completed because the biometric unit is currently being used for an enrollment transaction (system pool only).

WINBIO_E_UNKNOWN_ID

The biometric sample does not match any saved in the database.

 

Remarks

The value returned in 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

To use WinBioIdentify synchronously, call the function with a session handle created by calling WinBioOpenSession. The function blocks until the operation completes or an error is encountered.

To use WinBioIdentify asynchronously, call the function with a session handle created by calling WinBioAsyncOpenSession. The framework allocates a WINBIO_ASYNC_RESULT structure and uses it to return information about operation success or failure. If the operation is successful, the framework returns WINBIO_IDENTITY and WINBIO_BIOMETRIC_SUBTYPE information in a nested Identify structure. If the operation is unsuccessful, the framework returns WINBIO_REJECT_DETAIL information in the Identify structure. The WINBIO_ASYNC_RESULT structure is returned to the application callback or to the application message queue, depending on the value you set in the NotificationMethod parameter of the WinBioAsyncOpenSession function:

  • If you choose to receive completion notices by using a callback, you must implement a PWINBIO_ASYNC_COMPLETION_CALLBACK function and set the NotificationMethod parameter to WINBIO_ASYNC_NOTIFY_CALLBACK.
  • If you choose to receive completion notices by using the application message queue, you must set the NotificationMethod parameter to WINBIO_ASYNC_NOTIFY_MESSAGE. The framework returns a WINBIO_ASYNC_RESULT pointer to the LPARAM field of the window message.

To prevent memory leaks, you must call WinBioFree to release the WINBIO_ASYNC_RESULT structure after you have finished using it.

Windows 7:  You can perform this operation asynchronously by using the WinBioIdentifyWithCallback function. The function verifies the input arguments and returns immediately. If the input arguments are not valid, the function returns an error code. Otherwise, the framework starts the operation on another thread. When the asynchronous operation completes or encounters an error, the framework sends the results to the PWINBIO_IDENTIFY_CALLBACK function implemented by your application.

Examples

The following function calls WinBioEnumEnrollments to enumerate the biometric sub-factors enrolled for a template, and it calls WinBioIdentify to retrieve a WINBIO_IDENTITY object that identifies the user. Link to the Winbio.lib static library and include the following header files:

  • Windows.h
  • Stdio.h
  • Conio.h
  • Winbio.h

HRESULT EnumEnrollments( )
{
    // Declare variables.
    HRESULT hr = S_OK;
    WINBIO_IDENTITY identity = {0};
    WINBIO_SESSION_HANDLE sessionHandle = NULL;
    WINBIO_UNIT_ID unitId = 0;
    PWINBIO_BIOMETRIC_SUBTYPE subFactorArray = NULL;
    WINBIO_BIOMETRIC_SUBTYPE SubFactor = 0;
    SIZE_T subFactorCount = 0;
    WINBIO_REJECT_DETAIL rejectDetail = 0;
    WINBIO_BIOMETRIC_SUBTYPE subFactor = WINBIO_SUBTYPE_NO_INFORMATION;

    // 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;
    }

    // Locate the biometric sensor and retrieve a WINBIO_IDENTITY object.
    wprintf_s(L"\n Calling WinBioIdentify - Swipe finger on sensor...\n");
    hr = WinBioIdentify( 
            sessionHandle,              // Session handle
            &unitId,                    // Biometric unit ID
            &identity,                  // User SID
            &subFactor,                 // Finger sub factor
            &rejectDetail               // Rejection information
            );
    wprintf_s(L"\n Swipe processed - Unit ID: %d\n", unitId);
    if (FAILED(hr))
    {
        if (hr == WINBIO_E_UNKNOWN_ID)
        {
            wprintf_s(L"\n Unknown identity.\n");
        }
        else if (hr == WINBIO_E_BAD_CAPTURE)
        {
            wprintf_s(L"\n Bad capture; reason: %d\n", rejectDetail);
        }
        else
        {
            wprintf_s(L"\n WinBioEnumBiometricUnits failed. hr = 0x%x\n", hr);
        }
        goto e_Exit;
    }

    // Retrieve the biometric sub-factors for the template.
    hr = WinBioEnumEnrollments( 
            sessionHandle,              // Session handle
            unitId,                     // Biometric unit ID
            &identity,                  // Template ID
            &subFactorArray,            // Subfactors
            &subFactorCount             // Count of subfactors
            );
    if (FAILED(hr))
    {
        wprintf_s(L"\n WinBioEnumEnrollments failed. hr = 0x%x\n", hr);
        goto e_Exit;
    }

    // Print the sub-factor(s) to the console.
    wprintf_s(L"\n Enrollments for this user on Unit ID %d:", unitId);
    for (SIZE_T index = 0; index < subFactorCount; ++index)
    {
        SubFactor = subFactorArray[index];
        switch (SubFactor)
        {
            case WINBIO_ANSI_381_POS_RH_THUMB:
                wprintf_s(L"\n   RH thumb\n");
                break;
            case WINBIO_ANSI_381_POS_RH_INDEX_FINGER:
                wprintf_s(L"\n   RH index finger\n");
                break;
            case WINBIO_ANSI_381_POS_RH_MIDDLE_FINGER:
                wprintf_s(L"\n   RH middle finger\n");
                break;
            case WINBIO_ANSI_381_POS_RH_RING_FINGER:
                wprintf_s(L"\n   RH ring finger\n");
                break;
            case WINBIO_ANSI_381_POS_RH_LITTLE_FINGER:
                wprintf_s(L"\n   RH little finger\n");
                break;
            case WINBIO_ANSI_381_POS_LH_THUMB:
                wprintf_s(L"\n   LH thumb\n");
                break;
            case WINBIO_ANSI_381_POS_LH_INDEX_FINGER:
                wprintf_s(L"\n   LH index finger\n");
                break;
            case WINBIO_ANSI_381_POS_LH_MIDDLE_FINGER:
                wprintf_s(L"\n   LH middle finger\n");
                break;
            case WINBIO_ANSI_381_POS_LH_RING_FINGER:
                wprintf_s(L"\n   LH ring finger\n");
                break;
            case WINBIO_ANSI_381_POS_LH_LITTLE_FINGER:
                wprintf_s(L"\n   LH little finger\n");
                break;
            default:
                wprintf_s(L"\n   The sub-factor is not correct\n");
                break;
        }
 
    }

e_Exit:
    if (subFactorArray!= NULL)
    {
        WinBioFree(subFactorArray);
        subFactorArray = NULL;
    }

    if (sessionHandle != NULL)
    {
        WinBioCloseSession(sessionHandle);
        sessionHandle = NULL;
    }

    wprintf_s(L"\n Press any key to exit...");
    _getch();

    return hr;
}



Requirements

Minimum supported client

Windows 7 [desktop apps only]

Minimum supported server

Windows Server 2008 R2 [desktop apps only]

Header

Winbio.h (include Winbio.h)

Library

Winbio.lib

DLL

Winbio.dll

See also

WinBioIdentifyWithCallback

 

 

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