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cherryteastain • 06/15/2025 • 2 replies • view on HN

Why not just pass around an

    std::pair<void(*)(FuncData*), std;:unique_ptr<FuncData>>
at this stage? This implementation has a bunch of performance and ergonomics issues due to things like not using perfect forwarding for the Func1::Call(T) method, so for anything requiring copying or allocating it'll be a decent bit slower and you'll also be unable to pass anything that's noncopyable like an std::unique_ptr.

Replies

kjksf • 06/15/2025

I don't know fancy C++ so I don't understand your point about perfect forwarding.

But I do know the code I write and you're wrong about performance of Func0 and Func1. Those are 2 machine words and all it takes to construct them or copy them is to set those 2 fields.

There's just no way to make it faster than that, both at runtime or at compile time.

The whole point of this implementation was giving up fancy features of std::function in exchange for code that is small, fast (both runtime and at compilation time) and one that I 100% understand in a way I'll never understand std::function.

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badmintonbaseba • 06/16/2025

Just use std::function, you don't have to pass a lambda. Any callable is fine.