3 ms·

I like many parts of COM, but I believe that example mostly demonstrates bad parts, with IDL, registrations, and over-engineered support libraries. There's not

I like many parts of COM, but I believe that example mostly demonstrates bad parts, with IDL, registrations, and over-engineered support libraries. There's nothing wrong with exporting factory functions from DLLs. Microsoft does it all the time, APIs like Direct3D, DirectDraw and Media Foundation don't come with type libraries are they aren't registered anywhere. Speaking about support libraries, I once made my own: https://github.com/Const-me/ComLightInterop/tree/master/ComLightLib https://github.com/Const-me/ComLightInterop/tree/master/ComL... Compare examples from that article with this one: https://github.com/Const-me/ComLightInterop/blob/master/Demos/HelloWorldCpp/HelloWorld.cpp https://github.com/Const-me/ComLightInterop/blob/master/Demo... That source file is the complete DLL which implements a minimalistic COM object.

pjmlp 5y ago
With C++/CX and .NET Native they finally got it, after all these years Microsoft actually adopted Borland's productivity to COM, as done by C++ Builder and Delphi. Then they just managed to sink that ship with their UWP execution and the anti-C++/CX team that managed to deprecate it in name of C++/WinRT. It wouldn't be that bad if IDL tooling had actually improved since the ActiveX days.
_0w8t 5y ago
Media Foundation is registered as one is supposed to use CoCreateInstance() etc. to create various codecs, for example. But MF does not require CoInitialize() and indeed one can just use LoadLibrary() and lookup the factory function. That was handy when we needed to use MF in a sandboxed process when CoCreateInstance would fail due to sandbox restrictions on registry access.
- Const-me 5y ago
  > Media Foundation is registered Good point, albeit I think only higher-level pluggable pieces are registered. Most of these objects (IMFTopology, IMFSample, IMFMediaBuffer) can only be created with corresponding C APIs. > one is supposed to use CoCreateInstance() etc. to create various codecs I’m not sure about that, I think one is supposed to use APIs like MFTEnumEx to find and create these codecs. These things are also in registry, but in different key; CoCreateInstance normally looks under HKCR\CLSID but MF has another one, HKCR\MediaFoundation\Transforms. See also MFTRegister function, a quote from the documentation: This function does not register the CLSID of the MFT for the CoCreateInstance or CoGetClassObject functions

pjmlp 5y ago

With C++/CX and .NET Native they finally got it, after all these years Microsoft actually adopted Borland's productivity to COM, as done by C++ Builder and Delphi. Then they just managed to sink that ship with their UWP execution and the anti-C++/CX team that managed to deprecate it in name of C++/WinRT. It wouldn't be that bad if IDL tooling had actually improved since the ActiveX days.

_0w8t 5y ago

Media Foundation is registered as one is supposed to use CoCreateInstance() etc. to create various codecs, for example. But MF does not require CoInitialize() and indeed one can just use LoadLibrary() and lookup the factory function. That was handy when we needed to use MF in a sandboxed process when CoCreateInstance would fail due to sandbox restrictions on registry access.

Const-me 5y ago
> Media Foundation is registered Good point, albeit I think only higher-level pluggable pieces are registered. Most of these objects (IMFTopology, IMFSample, IMFMediaBuffer) can only be created with corresponding C APIs. > one is supposed to use CoCreateInstance() etc. to create various codecs I’m not sure about that, I think one is supposed to use APIs like MFTEnumEx to find and create these codecs. These things are also in registry, but in different key; CoCreateInstance normally looks under HKCR\CLSID but MF has another one, HKCR\MediaFoundation\Transforms. See also MFTRegister function, a quote from the documentation: This function does not register the CLSID of the MFT for the CoCreateInstance or CoGetClassObject functions