Interview with Zig language creator Andrew Kelley [video]

I work in HFT, and one of the key concerns when writing low-latency code is "is this code allocating memory, and if so, how can I stop it?" Zig is the perfect language for this use case as none of the standard library implicitly allocates, rather for anything that allocates, the caller must pass in an allocator. The stdlib also provides a handy arena allocator, which is often the best choice.

This is a huge advantage over C++ and Rust, because it makes it much harder for e.g. the intern to write code that repeatedly creates a vector or dynamically allocated string in a loop. Or to use something like std::unordered_map or std::deque that allocates wantonly.

Yeah when I heard about this I instantly thought of game engines, but it makes total sense for HFT too. "Modern C++", with all its constant little mallocs and frees is so awful for anything that requires ultra low latency

Can you explain how this is a problem in modern C++? I was under the impression that all the STL containers (string, vector, list, map, etc.) worked the same and have an allocator parameter. Are there other areas where these are missing? Or is the issue that STL implementations almost always default to an allocator that uses malloc? I'm not trying to dog on Zig here (it's a nice little language) but this just doesn't seem to be something that only Zig can do.