QT Include Windows SDK Library - c++

Question

I am new to Qt and I want to use the AudioSessionManager2 from the Windows SDK. In Qt Creator using this example I've written appended code below.
When compiling I get the messages
undefined reference to `__imp_CoCreateInstance'
undefined reference to `IID_IAudioSessionManager2'
In the documentation for the core audio APIs, Microsoft states the APIs are implemented in Mmdevapi.dll and Audioses.dll. While I hoped to find two matching .lib files the SDK I downloaded with Visual Studio, I only found mmdevapi.lib. After copying it to my project and adding it to the qt project file like below I still had no success with the same error message.
How am I supposed to know which lib files to import for which functions?
How do I get these lib files?
Did I import the lib file correctly?
audiomanager.h:
#ifndef AUDIOMANAGER_H
#define AUDIOMANAGER_H
#include <mmdeviceapi.h>
#include <audiopolicy.h>
#include "utils/SafeRelease.h"
class AudioManager {
public:
AudioManager();
~AudioManager();
private:
IAudioSessionManager2 *pSessionManager = nullptr;
HRESULT init();
};
#endif // AUDIOMANAGER_H
audiomanager.cpp
#include "audiomanager.h"
AudioManager::AudioManager () {
this->init();
}
AudioManager::~AudioManager () {
SafeRelease(&pSessionManager);
}
HRESULT AudioManager::init () {
HRESULT hr = S_OK;
// initialize needed vars
IMMDeviceEnumerator *pDeviceEnumerator = nullptr;
IMMDevice *pDevice = nullptr;
// get device enumerator
hr = CoCreateInstance(
__uuidof(MMDeviceEnumerator),
nullptr,
CLSCTX_ALL,
IID_PPV_ARGS(&pDeviceEnumerator)
);
if (FAILED(hr))
goto done;
// get the default audio output (for consoles)
// !!! only for consoles? (games, system, etc.), no music, video
pDeviceEnumerator->GetDefaultAudioEndpoint(eRender, eConsole, &pDevice);
if (FAILED(hr))
goto done;
// get the session manager
hr = pDevice->Activate(
IID_IAudioSessionManager2,
CLSCTX_ALL,
nullptr,
reinterpret_cast<void**>(&pSessionManager)
);
done:
SafeRelease(&pDeviceEnumerator);
SafeRelease(&pDevice);
return hr;
}
Line from Qt Project file
LIBS += "$$PWD\..\libs\mmdevapi.lib"

Answer 1

After hours of trying I figured out it would work with
// get the session manager
hr = pDevice->Activate(
__uuidof(IAudioSessionManager2),
CLSCTX_ALL,
nullptr,
reinterpret_cast<void**>(&pSessionManager)
);
instead of
// get the session manager
hr = pDevice->Activate(
IID_IAudioSessionManager2,
CLSCTX_ALL,
nullptr,
reinterpret_cast<void**>(&pSessionManager)
);
I don't know, why I cannot find proper libraries for the IID_IAudioSessionManager, nor why the Microsoft source code example lists this, but the other provided option seems to work.