set_locale docs

I was a little suprised that the docs neither state that the GNU locale library needs to be installed nor that the locales have to be gernerated in order to use the set_locale function with expected results. I just was using that function (on Debian testing), which did not exaclty do what i wanted it to. So i double checked for my locale settings and then realised the lib wasn't there and the needed locale was not generated. Maybe it's mentioned sowhere where i can't find it. Anyone with more knowledge may correct me. cheers, -ali