C++17

C++17 is a version of the ISO/IEC 14882 standard for the C++ programming language. C++17 replaced the prior version of the C++ standard, called C++14, and was later replaced by C++20. Before the C++ Standards Committee fixed a 3-year release cycle, C++17's release date was uncertain. In that time period, the C++17 revision was also called C++1z, following C++0x or C++1x for C++11 and C++1y for C++14. The C++17 specification reached the Draft International Standard (DIS) stage in March 2017. This DIS was unanimously approved, with only editorial comments, and the final standard was published in December 2017. Few changes were made to the C++ Standard Template Library, although some algorithms in the header were given support for explicit parallelization and some syntactic enhancements were made. C++17 introduced many new features. The following lists may be incomplete. Making the text message for optional Allow (as an alternative to ) in a template template parameter New rules for deduction from braced-init-list Nested namespace definitions, e.g., instead of Allowing attributes for namespaces and enumerators New standard attributes , and UTF-8 () character literals (UTF-8 string literals have existed since C++11; C++17 adds the corresponding character literals for consistency, though as they are restricted to a single byte they can only store "Basic Latin" and C0 control codes, i.e. ASCII) Hexadecimal floating-point literals Use of as the type for a non-type template parameter Constant evaluation for all non-type template arguments Fold expressions, for variadic templates A compile-time static with the form Structured binding declarations, allowing Initializers in and statements copy-initialization and direct-initialization of objects of type from prvalue expressions of type (ignoring top-level cv-qualifiers) shall result in no copy or move constructors from the prvalue expression. See copy elision for more information. Some extensions on over-aligned memory allocation Class template argument deduction (CTAD), introducing constructor deduction guides, e.