The example from bruno dot cenou at revues dot org below shows the possibility, but I want to spell it out: you can add charset info to setlocale.
Example:
Into my utf-8-encoded page I want to insert the name of the current month, which happens to be March, in German "März" - with umlaut. If you use
setlocale(LC_TIME, 'de_DE');
echo strftime("%B");
this will return "März", but that html-entity will look like this on a utf-8 page: "M?rz". Not what I want.
But if you use
setlocale(LC_TIME, 'de_DE.UTF8'); // note the charset info !
echo strftime("%B");
this returns "M√§rz", which, on utf-8, looks like it should: "März".
