AsioDriverList needs a balanced call of CoInitialize/CoUninitialize

[eyeco]

AsioDriverList needs a balanced call of CoInitialize/CoUninitialize just like, e.g., RtApiAsio, RtApiDs, or RtApiWasapi. The thing is that, if the application earlier already initialized COM using multithreading, then CoInitialize( NULL ) in the constructor of AsioDriverList will fail with RPC_E_CHANGED_MODE, in which case you must NOT call CoUninitialize() in the destructor, because if you do so, you are one uninit-call ahead, which causes a fail fast exception at the final CoUninitialize() at least in my code and I wouldn't know how to prevent this. The solution is to introduce a bool flag just like in RtApiDs and other parts of the code, e.g.:

constructor code:
coInitialized_ = false; HRESULT hr = CoInitialize( NULL ); if ( !FAILED( hr ) ) coInitialized_ = true;

destructor code:
if ( coInitialized_ ) CoUninitialize(); // balanced call.

idk if additional error handlingis required if the mode is not single-threaded apartment (which it would be in my case), frankly, idk what the reason for this requirement is in the first place, but what I do know is that there is an extra call of CoUninitialize.

[garyscavone]

I don't have access to a Windows system so it would be appreciated if you would submit a pull request with the fix.

[eyeco]

#438. Let me know if this works, I'm not familiar with how pull requests work, never made one. It's really just 5 lines of code.