86 ms·

On Windows, sure. On other platforms UTF-8 is generally preferable (in my opinion).

• jhallenworld 11y ago
  Annoyingly, there is no simple user accessible UTF-8 decoder in libc. The only standard way to use iswalpha is to convert to wchar_t first. One hack is to assume that bytes of UTF-8 encoded strings above 127 are all letters. It mostly works :-)
  • akira2501 11y ago
    > Annoyingly, there is no simple user accessible UTF-8 decoder in libc. Am I misunderstanding you, because I've always thought that's what the mbtowc(3) family of functions was?
    • jhallenworld 11y ago
      Well you are right, but these functions are not terribly fun to use. Consider a parsing function which extracts an identifier. For ASCII it's: if (isalpha(*s)) { *d++ = *s++; while (isalnum(*s)) *d++ = *s++; } To use UTF-8 / Unicode should require only small changes: if (iswalpha(decode(&s)) { encode(&d, advance(&s)); while (iswalnum(decode(&s)) encode(&d, advance(&s)); } For efficiency, don't decode twice- have the decoder return a pointer to the next sequence: if (iswalpha(c = utf8(&s, &n))) { encode(&d, c); s = n; while (iswalnum(c = utf8(&s, &n))) { encode(&d, c); s = n; } } Also should be able to match a string in line: if ('A' == utf8(&s, &t) && 'B' == utf8(&t, &s) && 'C' == utf8(&s, &t)) // we have 'ABC'.
    • sortie 11y ago
      mbtowc isn't necessarily thread safe, it's better to recommend mbrtowc.
  • sortie 11y ago
    Just use setlocale(LC_ALL, "") in main, and use mbrtowc to translate from whatever the system encoding is into the wchar_t type. There's no need to bake assumptions about the system encoding into most programs.