ref: 3f3bedb88862a0a955c8357081e4f8ba89b88b81
dir: /posix/utf.h/
#pragma once enum { Runeself = 0x80, Runeerror = 0xfffd, Runemax = 0x10ffff, UTFmax = 4, }; typedef uint32_t Rune; int chartorune(Rune *rune, const char *str); int runetochar(char *str, const Rune *rune); int runenlen(const Rune *r, int nrune); int fullrune(const char *str, int n); int runelen(Rune c); Rune tolowerrune(Rune c); Rune toupperrune(Rune c); Rune totitlerune(Rune c); int islowerrune(Rune c); int isupperrune(Rune c); int isalpharune(Rune c); int istitlerune(Rune c); int isspacerune(Rune c); int isdigitrune(Rune c); int utfnlen(const char *s, long m);