The limits may constrain quantities that include those described below or others. The bracketed number following each quantity is recommended as the minimum for that quantity. However, these quantities are only guidelines and do not determine compliance.
— Nesting levels of compound statements, iteration control structures, and selection control structures .
Your post made me chuckle Oria. I would imagine that the compiler would have a lot to do with it, although I'm curious what the standard for C++ says. I'd research it if I wasn't at work right now although in reality if you have a 128 nested if loop structure, you probably need to find another more optimal way to perform the operation.