C++20

See also C++11, C++17.

Some things that will be interesting to use once C++20 is common:

Feature	Since	Can use?	GCC	Apple Clang	Comment
std::span	C++20	from 1.3?	10	11.0.3	Handle buffers like standard library containers without risk of overflow.
std::format	C++20		13	N/A	Better and more efficient formatting of strings. Text Formatting
std::lerp	C++20	from 1.4?	9	11.0.3	Linear interpolation. (ui/tools/pencil-tool.cpp)
std::bit_floor	C++20	from 1.4?	9/10	11.0.3/13.0.0	Compute floor(log2(x)). (helper/mathfns.h)
Concepts	C++20	from 1.4?	6/10	12.0.0 Partial	Safer templating. (ui/controller.h)
Coroutines	C++20		10	10.0.1 Partial	Simpler asynchronous code. (trace/trace.cpp)
std::make_unique_for_overwrite	C++20		11	N/A	Don't zero arrays allocated using std::make_unique. (util/pool.cpp)
Ranges	C++20	from 1.4?		?	for (init; decl : expr). (ui/dialog/swatches.cpp)
Structural templates	C++20	from 1.4?		Partial	Allow instances of arbitrary literal classes as template parameters. (display/drawing.cpp)

As of 1 September 2023, the CI runners for:

• Linux:
  • appimage:linux GNU 9.4.0 (Using Ubuntu 20.04)
  • inkscape:linux GNU 11.4.0
• Windows
  • inkscape:windows:build Gnu 13.1.0
  • inkscape:windows:dist Same as above.
• macOS:
  • inkscape::macos:arm Apple Clang 13.1.6
  • inkscape:macos:x64: Apple Clang 14.0.0.

Errors and Deprecated items that we use:

• error: call of overloaded ‘lerp(double, double&, double&)’ is ambiguous (ui/knot/knot-holder-entity.cpp)
• warning: implicit capture of ‘this’ via ‘[=]’ is deprecated in C++20 [-Wdeprecated] https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0806r2.html
• warning: bitwise operation between different enumeration types ‘Box3D::Axis’ and ‘Box3D::FrontOrRear’ is deprecated [-Wdeprecated-enum-enum-conversion]