> Alloca is not standard C A similar option is a variable-length array, which is standard C. It does share the problem of not being available in some compilers

> Alloca is not standard C A similar option is a variable-length array, which is standard C. It does share the problem of not being available in some compilers, however. That said, there are other problems with alloca/VLAs. For small enough sizes, like you said it's faster and simpler to statically allocate. For large enough sizes, you risk overflowing the stack, which might be more constrained than you'd expect (especially when using threads). There might be a sweet spot where it's better, but it's not worth the portability cost and the potential headaches.