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.

how often does it happen that your interns work on the hot path of your trading systems, which is where I assume you care the most about avoid syscalls like malloc?

Nit pick: On modern systems malloc isn't a syscall, it's implemented in userspace. (Sorry, I couldn't help it)

That's not to say you're safe to call other syscalls, many of them either require memory allocations in-kernel (see ENOMEM) or can block indefinitely.

Never mind modern systems, malloc() was never a syscall :-) One of the great things about K&R is that it shows you how to implement parts of the C library, including a simple malloc(), demonstrating that the library does not need to be magical.