Open Standards. ↑ http://en.cppreference.com/w/cpp/language/auto ↑ This caused a conflict with the proposed use (common in other languages) of the underscore for digit grouping in numeric literals such as integer literals, so C++14 instead uses the apostrophe (as an upper comma) for grouping.Daveed Vandevoorde (2012-09-21). "N3448: Painless Digit Separation" (PDF). , Lawrence Crowl (2012-12-19). "N3499: Digit Separators". ↑ ISO/IEC (2003).