BluetoothGATTGetCharacteristics throwing Access violation reading location 0xFFFFFFF7 in BluetoothApis.dll

I am trying to write a Win32 console application that will connect iPhone Bluetooth for some BLE services. Please correct me if I am making any mistake here-

Getting Access violation error at -

hr = BluetoothGATTGetCharacteristics(
    hLEDevice,
    pServiceBuffer,
    0,
    NULL,
    &charBufferSize,
    BLUETOOTH_GATT_FLAG_NONE);

The reason is, I am not able to loop through - SetupDiEnumDeviceInterfaces for this device classId.

Main function for more detail-

#include "stdafx.h"
#include <stdio.h>
#include <windows.h>
#include <setupapi.h>
#include <devguid.h>
#include <regstr.h>
#include <bthdef.h>
#include <Bluetoothleapis.h>
#pragma comment(lib, "SetupAPI")
#pragma comment(lib, "BluetoothApis.lib")

HANDLE GetBLEHandle(__in GUID AGuid)
{
    HDEVINFO hDI;
    SP_DEVICE_INTERFACE_DATA did;
    SP_DEVINFO_DATA dd;
    GUID BluetoothInterfaceGUID = AGuid;
    HANDLE hComm = NULL;

    hDI = SetupDiGetClassDevs(&BluetoothInterfaceGUID, NULL, NULL, DIGCF_DEVICEINTERFACE | DIGCF_PRESENT);

    if (hDI == INVALID_HANDLE_VALUE) return NULL;

    did.cbSize = sizeof(SP_DEVICE_INTERFACE_DATA);
    dd.cbSize = sizeof(SP_DEVINFO_DATA);

    for (DWORD i = 0; SetupDiEnumDeviceInterfaces(hDI, NULL, &BluetoothInterfaceGUID, i, &did); i++)
    {
        SP_DEVICE_INTERFACE_DETAIL_DATA DeviceInterfaceDetailData;

        DeviceInterfaceDetailData.cbSize = sizeof(SP_DEVICE_INTERFACE_DETAIL_DATA);

        DWORD size = 0;

        if (!SetupDiGetDeviceInterfaceDetail(hDI, &did, NULL, 0, &size, 0))
        {
            int err = GetLastError();

            if (err == ERROR_NO_MORE_ITEMS) break;

            PSP_DEVICE_INTERFACE_DETAIL_DATA pInterfaceDetailData = (PSP_DEVICE_INTERFACE_DETAIL_DATA)GlobalAlloc(GPTR, size);

            pInterfaceDetailData->cbSize = sizeof(SP_DEVICE_INTERFACE_DETAIL_DATA);

            if (!SetupDiGetDeviceInterfaceDetail(hDI, &did, pInterfaceDetailData, size, &size, &dd))
                break;

            hComm = CreateFile(
                pInterfaceDetailData->DevicePath,
                GENERIC_WRITE | GENERIC_READ,
                FILE_SHARE_READ | FILE_SHARE_WRITE,
                NULL,
                OPEN_EXISTING,
                0,
                NULL);

            GlobalFree(pInterfaceDetailData);
        }
    }

    SetupDiDestroyDeviceInfoList(hDI);
    return hComm;
}


int main(int argc, char *argv[], char *envp[]){

GUID AGuid = GUID_DEVCLASS_BLUETOOTH;



//now get the handle 
HANDLE hLEDevice = GetBLEHandle(AGuid);


//Step 2: Get a list of services that the device advertises
// first send 0,NULL as the parameters to BluetoothGATTServices inorder to get the number of
// services in serviceBufferCount
USHORT serviceBufferCount;
////////////////////////////////////////////////////////////////////////////
// Determine Services Buffer Size
////////////////////////////////////////////////////////////////////////////

HRESULT hr = BluetoothGATTGetServices(
    hLEDevice,
    0,
    NULL,
    &serviceBufferCount,
    BLUETOOTH_GATT_FLAG_NONE);

if (HRESULT_FROM_WIN32(ERROR_MORE_DATA) != hr) {
    printf("BluetoothGATTGetServices - Buffer Size %d", hr);
}

PBTH_LE_GATT_SERVICE pServiceBuffer = (PBTH_LE_GATT_SERVICE)
    malloc(sizeof(BTH_LE_GATT_SERVICE) * serviceBufferCount);

if (NULL == pServiceBuffer) {
    printf("pServiceBuffer out of memory\r\n");
}
else {
    RtlZeroMemory(pServiceBuffer,
        sizeof(BTH_LE_GATT_SERVICE) * serviceBufferCount);
}

////////////////////////////////////////////////////////////////////////////
// Retrieve Services
////////////////////////////////////////////////////////////////////////////

USHORT numServices;
hr = BluetoothGATTGetServices(
    hLEDevice,
    serviceBufferCount,
    pServiceBuffer,
    &numServices,
    BLUETOOTH_GATT_FLAG_NONE);

if (S_OK != hr) {
    printf("BluetoothGATTGetServices - Buffer Size %d", hr);
}


//Step 3: now get the list of charactersitics. note how the pServiceBuffer is required from step 2
////////////////////////////////////////////////////////////////////////////
// Determine Characteristic Buffer Size
////////////////////////////////////////////////////////////////////////////

USHORT charBufferSize;
hr = BluetoothGATTGetCharacteristics(
    hLEDevice,
    pServiceBuffer,
    0,
    NULL,
    &charBufferSize,
    BLUETOOTH_GATT_FLAG_NONE);

if (HRESULT_FROM_WIN32(ERROR_MORE_DATA) != hr) {
    printf("BluetoothGATTGetCharacteristics - Buffer Size %d", hr);
}

PBTH_LE_GATT_CHARACTERISTIC pCharBuffer;
if (charBufferSize > 0) {
    pCharBuffer = (PBTH_LE_GATT_CHARACTERISTIC)
        malloc(charBufferSize * sizeof(BTH_LE_GATT_CHARACTERISTIC));

    if (NULL == pCharBuffer) {
        printf("pCharBuffer out of memory\r\n");
    }
    else {
        RtlZeroMemory(pCharBuffer,
            charBufferSize * sizeof(BTH_LE_GATT_CHARACTERISTIC));
    }


    USHORT numChars;
    hr = BluetoothGATTGetCharacteristics(
        hLEDevice,
        pServiceBuffer,
        charBufferSize,
        pCharBuffer,
        &numChars,
        BLUETOOTH_GATT_FLAG_NONE);

    if (S_OK != hr) {
        printf("BluetoothGATTGetCharacteristics - Actual Data %d", hr);
    }

    if (numChars != charBufferSize) {
        printf("buffer size and buffer size actual size mismatch\r\n");
    }
}

Getting error

Unhandled exception at 0x0F5CE138 (BluetoothApis.dll) in ConsoleApplication.exe: 0xC0000005: Access violation reading location 0xFFFFFFF7

Can anyone suggest what could be the cause?

I tried with a C# desktop application but no luck there also getting the FileNotFound error at the line "await GattDeviceService.FromIdAsync(device.Id)"

The question is old, but there still no answer. This is due to GetBLEHandle function that returned NULL. AGuid is a GUID of BLE device (in Microsoft samples it's HRM - heart rate monitor), you have no device with this GUID connected. So NULL from GetBLEHandle is DEVICE_NOT_FOUND. And if you'll call BluetoothGATTGetServices with NULL deviceHandle you'll receive such exception.