1 Here is a description of how you can use STLport to read/write utf8 files. 2 utf8 is a way of encoding wide characters. As so, management of encoding in 3 the C++ Standard library is handle by the codecvt locale facet which is part 4 of the ctype category. However utf8 only describe how encoding must be 5 performed, it cannot be used to classify characters so it is not enough info 6 to know how to generate the whole ctype category facets of a locale 7 instance. 8 9 In C++ it means that the following code will throw an exception to 10 signal that creation failed: 11 12 #include <locale> 13 // Will throw a std::runtime_error exception. 14 std::locale loc(".utf8"); 15 16 For the same reason building a locale with the ctype facets based on 17 UTF8 is also wrong: 18 19 // Will throw a std::runtime_error exception: 20 std::locale loc(locale::classic(), ".utf8", std::locale::ctype); 21 22 The only solution to get a locale instance that will handle utf8 encoding 23 is to specifically signal that the codecvt facet should be based on utf8 24 encoding: 25 26 // Will succeed if there is necessary platform support. 27 locale loc(locale::classic(), new codecvt_byname<wchar_t, char, mbstate_t>(".utf8")); 28 29 Once you have obtain a locale instance you can inject it in a file stream to 30 read/write utf8 files: 31 32 std::fstream fstr("file.utf8"); 33 fstr.imbue(loc); 34 35 You can also access the facet directly to perform utf8 encoding/decoding operations: 36 37 typedef std::codecvt<wchar_t, char, mbstate_t> codecvt_t; 38 const codecvt_t& encoding = use_facet<codecvt_t>(loc); 39 40 Notes: 41 42 1. The dot ('.') is mandatory in front of utf8. This is a POSIX convention, locale 43 names have the following format: 44 language[_country[.encoding]] 45 46 Ex: 'fr_FR' 47 'french' 48 'ru_RU.koi8r' 49 50 2. utf8 encoding is only supported for the moment under Windows. The less common 51 utf7 encoding is also supported. 52
