[kps]

VLAs were added in C99, but not universally adopted (particularly by embedded systems compilers, for obvious reasons), and then made optional in C11.

[DSMan195276]

You're completely right, but I think it's worth clarifying that VLA notation in parameter lists, and actual VLAs are two completely different things. The example he showed doesn't actually use a VLA, it just looks like it does.

[pantalaimon]

I don't see an obvious reason - that's all information that's available on compile-time, there should be no additional run-time cost - or what are you implying?

[gcp]

VLA allows for run-time size determination, not compile time