How to Initialize HRESULT for SetMasterVolume? - c++

Question

#include <iostream>
#include <windows.h>
#include <Audioclient.h>
int main(){
ShellExecute(NULL, "open", "https://www.youtube.com/watch?v=zf2VYAtqRe0", NULL, NULL, SW_SHOWNORMAL);
HRESULT SetMasterVolume(1.0, NULL);
return();
}
Okay so I'm trying to code this program, that opens a YouTube song, and turns up the volume at the same time. I don´t understand the error I get.
ERROR : C2440 ´initializing´: cannot convert from ´initializer list´ to ´HRESULT´
So therefore my question is: how do I initialize HRESULT so SetMasterVolume works? Or, how to setup SetMasterVolume? And please, if possible, explain why I cant just write
SetMasterVolume(1.0,NULL);
When I have included audioclient.h

Answer 1

ISimpleAudioVolume::SetMasterVolume is a COM method, it is not a regular WinAPI. You get a compile error when you just type in the function. Adding HRESULT in front of it will cause a different C++ error.
Use this code instead, with SetMasterVolumeLevelScalar
Based on code from:
Change Master Volume in Visual C++
#include <Windows.h>
#include <Mmdeviceapi.h>
#include <Endpointvolume.h>
BOOL ChangeVolume(float nVolume)
{
HRESULT hr = NULL;
IMMDeviceEnumerator *deviceEnumerator = NULL;
hr = CoCreateInstance(__uuidof(MMDeviceEnumerator), NULL, CLSCTX_INPROC_SERVER,
__uuidof(IMMDeviceEnumerator), (LPVOID *)&deviceEnumerator);
if(FAILED(hr))
return FALSE;
IMMDevice *defaultDevice = NULL;
hr = deviceEnumerator->GetDefaultAudioEndpoint(eRender, eConsole, &defaultDevice);
deviceEnumerator->Release();
if(FAILED(hr))
return FALSE;
IAudioEndpointVolume *endpointVolume = NULL;
hr = defaultDevice->Activate(__uuidof(IAudioEndpointVolume),
CLSCTX_INPROC_SERVER, NULL, (LPVOID *)&endpointVolume);
defaultDevice->Release();
if(FAILED(hr))
return FALSE;
hr = endpointVolume->SetMasterVolumeLevelScalar(nVolume, NULL);
endpointVolume->Release();
return SUCCEEDED(hr);
}
int main()
{
CoInitialize(NULL);
ChangeVolume(0.5);
CoUninitialize();
return 0;
}

Answer 2

You need to give it a name and assign to it.
HRESULT hResult = SetMasterVolume(1.0, NULL);