How to detect if a Microphone is present

I just had a very long tech support call because a customer didn't have a Mic on their laptop. (Stupid me: they said they'd used the mic earlier and I have never heard of a laptop not having a Mic).

I'm wondering if there is a way to detect whether there is a Microphone (recording capability) on Windows XP, Vista, 7.

(I've got error handling enabled and it logs the error and then exits t开发者_StackOverflow社区he Function but the app just crashes on Windows 7 if there's no Microphone. )

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I'd use IMMDeviceEnumerator::GetDefaultAudioEndpoint - this returns the default audio device for the specified role and data flow.

In particular, you would use:

    CComPtr<IMMDeviceEnumerator> pEnumerator;
    CComPtr<IMMDevice> pDevice;

    hr = CoCreateInstance(__uuidof(MMDeviceEnumerator), NULL,
           CLSCTX_ALL, IID_PPV_ARGS(&pEnumerator));
    if (SUCCEEDED(hr))
    {
        hr = pEnumerator->GetDefaultAudioEndpoint(eCapture, eConsole, &pDevice);
    }
    if (!pDevice || hr == ERROR_NOT_FOUND)
    {
           // no microphone
    }

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Check out System Tray Audio Device Switcher

In this VB source code you will an example on how to enumerate audio I/O devices.

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in C++

#include "stdafx.h"
#include "Mmdeviceapi.h"
#include <atlbase.h>


int _tmain(int argc, _TCHAR* argv[])
{
    CoInitializeEx(NULL, COINIT_MULTITHREADED);

    CComPtr<IMMDeviceEnumerator> pEnumerator = NULL;
    CComPtr<IMMDevice> pDevice;
    const CLSID CLSID_MMDeviceEnumerator = __uuidof(MMDeviceEnumerator);
    const IID IID_IMMDeviceEnumerator = __uuidof(IMMDeviceEnumerator);
    HRESULT hr = CoCreateInstance(
        CLSID_MMDeviceEnumerator, NULL,
        CLSCTX_ALL, IID_IMMDeviceEnumerator,
        (void**)&pEnumerator);

    if (FAILED(hr))
    {
        printf("failed");
    }
    else
    {
        hr = pEnumerator->GetDefaultAudioEndpoint(eCapture, eConsole, &pDevice);

        if (!pDevice || hr == ERROR_NOT_FOUND)
        {
            printf("no microphone");
        }
        else
        {
            printf("microphone present");
        }

    }

    return 0;
}

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I think the only way you will be able to do this in VB 6 is through Direct X:

http://msdn.microsoft.com/en-us/library/bb318770(VS.85).aspx

You can check this out:

http://msdn.microsoft.com/en-us/library/bb280815(VS.85).aspx

CaptureDevices Collection Class (Microsoft.DirectX.DirectSound)

http://msdn.microsoft.com/en-us/library/ms810619.aspx

you can also call dxdiag..