Previous: Non-reentrant Conversion, Up: Character Set Handling


6.5 Generic Charset Conversion

The conversion functions mentioned so far in this chapter all had in common that they operate on character sets that are not directly specified by the functions. The multibyte encoding used is specified by the currently selected locale for the LC_CTYPE category. The wide character set is fixed by the implementation (in the case of GNU C library it is always UCS-4 encoded ISO 10646.

This has of course several problems when it comes to general character conversion:

The XPG2 standard defines a completely new set of functions, which has none of these limitations. They are not at all coupled to the selected locales, and they have no constraints on the character sets selected for source and destination. Only the set of available conversions limits them. The standard does not specify that any conversion at all must be available. Such availability is a measure of the quality of the implementation.

In the following text first the interface to iconv and then the conversion function, will be described. Comparisons with other implementations will show what obstacles stand in the way of portable applications. Finally, the implementation is described in so far as might interest the advanced user who wants to extend conversion capabilities.