be careful with the LC_ALL setting, as it may introduce some unwanted conversions. For example, I used 

setlocale (LC_ALL, "Dutch");

to get my weekdays in dutch on the page. From that moment on (as I found out many hours later) my floating point values from MYSQL where interpreted as integers because the Dutch locale wants a comma (,) instead of a point (.) before the decimals. I tried printf, number_format, floatval.... all to no avail. 1.50 was always printed as 1.00 :(

When I set my locale to :

 setlocale (LC_TIME, "Dutch");

my weekdays are good now and my floating point values too. 

I hope I can save some people the trouble of figuring this out by themselves.

Rob