luaO_pushvfstring
ret = luaO_pushvfstring(L, fmt, argp);
ret = luaO_pushvfstring(L, fmt, argp);
addinfo(L, luaO_pushvfstring(L, fmt, argp));
msg = luaO_pushvfstring(L, fmt, argp);
LUAI_FUNC const char *luaO_pushvfstring (lua_State *L, const char *fmt,