## 8.1 ISO8859-1 Character Encoding support under Windows

The Mozart programming system uses the ISO8859-1 character encoding system, no matter the platform it is running on. However under Windows the Tcl/Tk process that serves as the front-end graphical user interface can only use the UTF-8 character encoding. This is a Windows specific problem as Tcl/Tk uses also ISO8859-1 undex Linux, Unix, and Mac OS X.

Many characters are common between the two encodings, however more specialized ones like accentuated characters are not. QTk embeds an automatic translation mechanism between the two sets under Windows. Mozart application developpers should care only about the ISO8859-1 encoding system on all platforms including Windows. The translation mechanism works like this:

- If a character exists in both encodings, then it is directly translated.

- ISO8859-1 doesn't support the euro currency symbol. This symbol is represented by the (arbitrarily choosen) character number 158 at the Oz side.

- The characters that exist in UTF-8 but not in ISO8859-1 are translated into an escape sequence: `27|N|X1|...|Xn` where `N` is the number of `Xi` present, and `X1|..|Xn` is the UTF-8 encoding of the character.

- There are no characters existing in ISO8859-1 but not in UTF-8.