Currency name before and after value

Hi,

I need to manage currency display in my program.
I would like to know how can i do to detect if currency code/name should 
be placed before the amount/value or after.

e.g.
USD 1234,56 / USD -1234,56
$ 1234,56 / $ - 1234,56

1234.56 EUR / -1234.56 EUR
1234.56 EUR / -1234.56 EUR

i understood that "comma" or "dot" can be found using: 
setlocale(LC_MONETARY,'en_US');
but how can i know if currency needs to have currency name before or 
after amount ?
thx.

A.