Talk:cpp/io/c/vfprintf

If I understand correctly, the invocation

   int bytes = std::vsnprintf(NULL, 0, fmt, args);

will _not_ include the null terminator in the count of the number of bytes to be written, even though the other forms will include a null terminator. Is that correct? Would it be worth making that point explicit on this page?

Good point. This page says it under "Return value" and also uses it in the example, where it does std::vector<char> buf(1+std::vsnprintf(NULL, 0, fmt, args1));. And the page on std::snprintf also says it under "Return value" and makes a slightly larger note with std::vector<char> buf(sz + 1); // note +1 for null terminator, but the C standard actually says right in the desc "not counting the terminating null character," - now done the same here. --Cubbi (talk) 12:18, 4 April 2018 (PDT)