memory leak in c++ console program calling Windows APIs - c++

Question

I have copied some code I found on-line here. I have successfully run it but if I run it in a loop, there is a bad memory leak. I program mostly in C#, and this example goes way over my head. Could somebody point me in the right direction to fixing the memory leak? Here is my C++ console application in it's entirety. Any help is appreciated. Thanks.
// ConsoleApplication1.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include <iostream>
#include "Netlistmgr.h"
bool checkForCaptivePortalMode()
{
bool fCaptivePortalDetected = false;
// Initialize COM.
if (SUCCEEDED(CoInitializeEx(NULL, COINIT_MULTITHREADED)))
{
// Declare a pointer to INetworkListManager
INetworkListManager* pNetworkListManager;
// Create instance of the CLSID_NetworkListManger COM object
if (SUCCEEDED(CoCreateInstance(CLSID_NetworkListManager, NULL,
CLSCTX_ALL, IID_INetworkListManager,
(LPVOID*)&pNetworkListManager)))
{
// Declare pointer to an IEnumNetworkConnections
IEnumNetworks* pEnum;
// Call to GetNetworks from INetworkListManager interface
if (SUCCEEDED(pNetworkListManager->GetNetworks
(NLM_ENUM_NETWORK_CONNECTED, &pEnum)) && pEnum != NULL)
{
INetwork *pINetwork;
HRESULT hr = pEnum->Next(1, &pINetwork, nullptr);
while (hr == S_OK)
{
if (pINetwork != NULL)
{
IPropertyBag *pNetworkPropertyBag;
HRESULT hrQueryInterface = pINetwork->QueryInterface
(IID_IPropertyBag, (LPVOID*)&pNetworkPropertyBag);
if (SUCCEEDED(hrQueryInterface) && pNetworkPropertyBag != nullptr)
{
NLM_CONNECTIVITY networkConnectivity;
VARIANT variantConnectivity;
if (SUCCEEDED(pINetwork->GetConnectivity(&networkConnectivity)))
{
if ((networkConnectivity &
NLM_CONNECTIVITY_IPV4_INTERNET) == NLM_CONNECTIVITY_IPV4_INTERNET)
{
VariantInit(&variantConnectivity);
if (SUCCEEDED(pNetworkPropertyBag->Read
(NA_InternetConnectivityV4, &variantConnectivity, nullptr))
&& (V_UINT(&variantConnectivity) &
NLM_INTERNET_CONNECTIVITY_WEBHIJACK) ==
NLM_INTERNET_CONNECTIVITY_WEBHIJACK)
{
fCaptivePortalDetected = true;
}
auto t = V_UINT(&variantConnectivity);
VariantClear(&variantConnectivity);
}
if (!fCaptivePortalDetected && (networkConnectivity
& NLM_CONNECTIVITY_IPV6_INTERNET) == NLM_CONNECTIVITY_IPV6_INTERNET)
{
VariantInit(&variantConnectivity);
if (SUCCEEDED(pNetworkPropertyBag->Read(NA_InternetConnectivityV6,
&variantConnectivity, nullptr)) &&
(V_UINT(&variantConnectivity) &
NLM_INTERNET_CONNECTIVITY_WEBHIJACK) ==
NLM_INTERNET_CONNECTIVITY_WEBHIJACK)
{
fCaptivePortalDetected = true;
}
VariantClear(&variantConnectivity);
}
}
}
pINetwork->Release();
}
if (fCaptivePortalDetected)
break;
hr = hr = pEnum->Next(1, &pINetwork, nullptr);
}
}
}
}
// Uninitialize COM.
// (This should be called on application shutdown.)
CoUninitialize();
return fCaptivePortalDetected;
}
int main()
{
for (;;)
{
bool check = checkForCaptivePortalMode();
std::cout << "\n" << check;
//char c = std::getchar();
}
return 0;
}

Answer 1

For one thing you never call pNetworkListManager->Release(). More generally, in C++ if you are not using smart pointers you must make sure each and every resource allocation has a matching deallocation. It would be easier and probably make your code simpler if you used smart pointers throughout.