alt Hacker Newsalloca() is super useful, but it's also quite dangerous because you can easily overflow the stack.
The obvious issue is that you can't know how much space is left on the stack, so you basically have to guess and pick an arbitrary "safe" size limit. This gets even more tricky when functions may be called recursively.
The more subtle issue is that the stack memory returned by alloca() has function scope and therefore you must never call it directly in a loop.
I use alloca() on a regular basis, but I have to say there are safer and better alternatives, depending on the particular use case: arena/frame allocators, threadlocal pseudo-stacks, static vectors, small vector optimizations, etc.
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If you have well defined boundaries, you can move the stack to an arbitrarily large chunk of memory before the recursive call and restore it to the system stack upon completion.
> alloca() is super useful, but it's also quite dangerous because you can easily overflow the stack.
This is not a problem for Go, because it has resizable stacks.
> The obvious issue is that you can't know how much space is left on the stack [...]
Oh, huh. I've never actually tried it, but I always assumed it would be possible to calculate this, at least for a given OS / arch. You just need 3 quantities, right? `remaining_stack_space = $stack_address - $rsp - $system_stack_size`.
But I guess there's no API for a program to get its own stack address unless it has access to `/proc/$pid/maps` or similar?