alt Hacker NewsC++ ABIs are why Win32 settled on things like COM to do cross-module passing of objects. Because nobody could agree on a standard, the COM standard enforced a very specific calling convention, and a very specific vtable layout for COM objects.
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mohamedkoubaa • today at 3:12 PM
Given OOP, the only ABI for an object is a vtable and that is left unspecified (for good reason) by the C++ standard.
COM said, "objects are cool and modules are cool so we need an ABI for objects" and specified a vtable. It isn't the only programming model which continued from the same observation: Python did too with its absolutely abysmal leaky PyObject ABI
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Not only, there is also XPC and IO/DriverKit on Apple, Android IPC, D-BUS, FIDL on Fucshia,....
Also C ABI also does not exist, people keep mistaking the ABI of their favourite C compiler with the OS ABI, which only overlap if the OS was written in C to start with.
For example on mainframes and micros, naturally not written in C, it is either a bytecode based ABI like TIMI on IBM i, or language environments like on z/OS, ClearPath MCP, OS 2200 and so forth.
And as a reminder, from a famous WG14 and WG21 member, and former Rust contributor,
"To Save C, We Must Save ABI"
https://thephd.dev/to-save-c-we-must-save-abi-fixing-c-funct...