Editing Printf (section)

===2020s: std::print ===

To address usability issues with the existing [[C++]] [[input/output (C++)|input/output support]], as well as avoid safety issues of printf<ref>{{cite web|url=https://hownot2code.wordpress.com/2016/08/10/beware-of-printf|title=How Not to Code: Beware of printf|date=10 August 2016 }}</ref> the [[C++ standard library]] was revised<ref>{{cite web|url=https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p2216r2.html|title=C++20 Format improvements proposal to enable compile-time checks}}</ref> to support a new type-safe formatting starting with [[C++20]].<ref>{{cite web|url=https://en.cppreference.com/w/cpp/utility/format/format|title=C++20 std::format}}</ref> The approach of {{code|std::format|cpp}} resulted from incorporating Victor Zverovich's {{code|libfmt}}<ref>{{cite web|url=https://fmt.dev|title=libfmt: a modern formatting library}}</ref> API into the language specification<ref>{{cite web|url=https://www.accu.org/journals/overload/29/166/collyer/|title=C++20 Text Formatting: An Introduction}}</ref> (Zverovich wrote<ref>{{cite web|url=https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p0645r10.html|title=C++ Format Proposal History}}</ref> the first draft of the new format proposal); consequently, {{code|libfmt}} is an implementation of the C++20 format specification. In [[C++23]], another function, {{code|std::print|cpp}}, was introduced that combines formatting and outputting and therefore is a functional replacement for {{code|printf()}}.<ref>{{cite web|url=https://en.cppreference.com/w/cpp/io/print|title=C++ print}}</ref>

As the format specification has become a part of the language syntax, a C++ compiler is able to prevent invalid combinations of types and format specifiers in many cases. Unlike the {{kbd|-Wformat}} option, this is not an optional feature.

The format specification of {{code|libfmt}} and {{code|std::format|cpp}} is, in itself, an extensible "mini-language" (referred to as such in the specification),<ref>{{cite web|url=https://fmt.dev/6.2.1/syntax.html#format-specification-mini-language|title=Format Specification Mini-Language}}</ref> an example of a [[domain-specific language]]. As such, {{code|std::print|cpp}}, completes a historical cycle; bringing the state-of-the-art (as of 2024) back to what it was in the case of Fortran's first {{code|PRINT|fortran}} implementation in the 1950s<!--overly colorful and debatable-->.