ref: f200ab4cf210045ab7424d68a11b7cb0ccd3b9d6
dir: /sys/src/libc/fmt/vsnprint.c/
#include <u.h> #include <libc.h> int vsnprint(char *buf, int len, char *fmt, va_list args) { Fmt f; if(len <= 0) return -1; f.runes = 0; 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); *(char*)f.to = '\0'; return (char*)f.to - buf; }