I very much doubt Metal or Core Audio are implemented in ObjC. C++ or C are much more likely candidates, and is what Apple is generally using for low level code like that...

And Core Animation is all C++ under the hood.

NeXT drivers were in Objective-C.

And you will find plenty of Apple folks at WWDC that resent that decision and would gladly have it back in Objective-C.

As for performance issues, that is the same talk about C devs regarding using C++ on kernel space, go figure.

> Metal is written in Objective-C, is based on Foundation, and makes use of Grand Central Dispatch to synchronize between the CPU and GPU.

https://www.objc.io/issues/18-games/metal/

> Shading Language: C++14, Runtime/API: Objective-C

https://en.wikipedia.org/wiki/Metal_(API)

>And you will find plenty of Apple folks at WWDC that resent that decision and would gladly have it back in Objective-C.

I'm sure you can find 10 of such folks. I doubt you can find 50.

Those 10 are most likely former NeXTSTEP developers that actually know what they are talking about.

...for the time...

Ask C engineers about DriverKit, Treble drivers, UDMF, mbed, GenodeOS and they will answer exactly the same way about C++.

Certainly not objc. Maybe objc++ where everything but the interface is cpp.

> Metal is written in Objective-C, is based on Foundation, and makes use of Grand Central Dispatch to synchronize between the CPU and GPU.

https://www.objc.io/issues/18-games/metal/

C++ is used for Metal shaders.