Yep. Because of the terribleness of locales, you should always just roll your own to handle ascii, or use an explicitly unicode-aware function. Anything in lib

Yep. Because of the terribleness of locales, you should always just roll your own to handle ascii, or use an explicitly unicode-aware function. Anything in libc that relies on locale is unusable because of this. Besides, isspace is such a trivial function that you don’t want to actually call an extern function (possibly even dynamically linked and thus having to hit the PLT) for it, you want something that is easily inlined.