Re:I learnt C++ in 2018 and have no regrets
by Const-me on Tuesday January 08, 2019 @02:22AM
(#18853918)
> COM in its essence defines two things
COM is quite a lot of things. Also threading model, date-time-currency formats, late binding/dynamic dispatch/scripting, type info both runtime and design time, IPC, RPC, security, and more.
> What you think of inheritance can be implemented with a struct containing nested structs of function pointers
What I think of inheritance in the context of COM is called “aggregation” and it’s more complex than that.
> It's not insurmountable
It’s not, but you’ll spend ~2x more time doing that compared to C++, and ~4x more time compared to VBScript or .NET.
Update: that 2x-4x is for implementation. For consumption C++ and .NET are close, but anything else is more complex due to FFI in between. C++ or VBScript don’t need FFI, .NET runtime is designed around many key parts of COM e.g. they have reused HRESULT’s and type info format.
COM is quite a lot of things. Also threading model, date-time-currency formats, late binding/dynamic dispatch/scripting, type info both runtime and design time, IPC, RPC, security, and more.
> What you think of inheritance can be implemented with a struct containing nested structs of function pointers
What I think of inheritance in the context of COM is called “aggregation” and it’s more complex than that.
> It's not insurmountable
It’s not, but you’ll spend ~2x more time doing that compared to C++, and ~4x more time compared to VBScript or .NET.
Update: that 2x-4x is for implementation. For consumption C++ and .NET are close, but anything else is more complex due to FFI in between. C++ or VBScript don’t need FFI, .NET runtime is designed around many key parts of COM e.g. they have reused HRESULT’s and type info format.