ref: 71a993b4ca2c455f491aad669e3a4ac2979f6bb8
dir: /sys/src/libc/fmt/runevsnprint.c/
#include <u.h> #include <libc.h> int runevsnprint(Rune *buf, int len, char *fmt, va_list args) { Fmt f; if(len <= 0) return -1; f.runes = 1; f.start = buf; f.to = buf; f.stop = buf + len - 1; f.flush = nil; f.farg = nil; f.nfmt = 0; f.args = args; dofmt(&f, fmt); *(Rune*)f.to = '\0'; return (Rune*)f.to - buf; }