Usage of IMMNotificationClient to register endpoint notifications
lazarus / 34-Windows

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Nevada Smith · 2022-05-19 14:34

I am trying to use Windows Core API to register for notifications on
audio device changes.

I am able to create a IMMDeviceEnumerator.

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i DeviceEnum
:= CreateComObject(CLASS_IMMDeviceEnumerator) as IMMDeviceEnumerator;
As the next step, I need to use RegisterEndpointNotificationCallback
to register for notifications. I am assuming I have to do something
like, but I might be wrong.

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i OleCheck(De
viceEnum.RegisterEndpointNotificationCallback(IMMNotificationClient(@N
otificationClient)));
However, I do not know how to instantiate IMMNotificationClient.
1. If I have to use CreateComObject , I do not know the CLSID. I have
gone through header files in Mingw, but I could not find the CLSID.
2. In certain C projects, they mock a C++ (COM) object starting with a
struct and then by adding appropriate methods.

Please advise...

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Nevada Smith · 2022-05-19 17:52

This was sort of a stupid question. It was as simple as :

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
TDeviceListener = class(TObject, IMMNotificationClient)
You have to implement the virtual methods from IUnknown from which
IMMNotificationClient is derived.
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i function
TDeviceListener.QueryInterface(constref  iid: TGuid; out obj):
HRESULT;  stdcall;begin     // Returning S_OK blinging is not entirely
correct, but sort of does the job for proof-of-concept     Result :=
S_OK;end; function TDeviceListener._AddRef(): HRESULT; stdcall;begin 
Inc(FRefCount);  Result:=FRefCount;end; function
TDeviceListener._Release(): HRESULT; stdcall;begin  Dec(FRefCount); 
Result:=FRefCount;end;                                               
                          
And then use it 

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
OleCheck(DeviceEnum.RegisterEndpointNotificationCallback(Self));

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trev · 2022-05-20 03:48

Thanks for bothering return to let us know how you solved the issue.
It may well help another user in the future.

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PascalDragon · 2022-05-20 14:09

Quote from: Nevada Smith on May 19, 2022, 07:52:33 pmThis was sort of
a stupid question. It was as simple as :

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
TDeviceListener = class(TObject, IMMNotificationClient)
Best inherit from TInterfacedObject instead of TObject as that already
provides suitable implementations for QueryInterface, _AddRef and
_Release.