LANG=sk_SK.UTF-8
LC_CTYPE="sk_SK.UTF-8"
LC_NUMERIC="sk_SK.UTF-8"
LC_TIME="sk_SK.UTF-8"
LC_COLLATE="sk_SK.UTF-8"
LC_MONETARY="sk_SK.UTF-8"
LC_MESSAGES="sk_SK.UTF-8"
LC_PAPER="sk_SK.UTF-8"
LC_NAME="sk_SK.UTF-8"
LC_ADDRESS="sk_SK.UTF-8"
LC_TELEPHONE="sk_SK.UTF-8"
LC_MEASUREMENT="sk_SK.UTF-8"
LC_IDENTIFICATION="sk_SK.UTF-8"
LC_ALL=

...
setlocale(LC_COLLATE,"sk_SK.UTF-8");
setlocale(LC_MONETARY,"sk_SK.UTF-8");
setlocale(LC_MESSAGES,"sk_SK.UTF-8");
...
setlocale(LC_ALL,"C");