The CopperSpice libraries are migrating to C++20 to leverage new and enhanced functionality in the core language. The build files for all projects which link with CopperSpice 2.0 or newer must be modified to specify which standard to use when compiling.
The build file for all prior examples in this Journal require one minor change as explained in this article.
New Stuff
Transitioning to C++20 allowed us to use concepts, enable newer functionality in std::chrono, improve our unit tests, and trap additional type conversion warnings.
There were two changes we made to CopperSpice which had the most effect and improved the code base. These are described below.
** Spaceship
Three-way comparison operator is also known as the “spaceship operator” because of the shape of the operator, which is <=>. This operator is used to compare two values and determine their equality or if one is less than or greater than the other value.
This new operator simplifies implementing comparison operations and usually results in more efficient code.
** char8_t
A string literal is a sequence of characters enclosed in double quotes. For example, “Hello CopperSpice”. String literals are commonly used to initialize the value of an std::string or a QString.
C++11 added a UTF-16 string literal which has the data type of char16_t and UTF-32 string literals with a data type of char32_t. The standard committee forgot to add a new data type for UTF-8 string literals. This was corrected in C++20.
Prior to C++20 the data type of a UTF-8 string literal was char. With the release of C++20 a UTF-8 string literal finally has a unique data type of char8_t.
Update Build File for Journal Examples
Examples 1 through 47 were compiled with C++17 and on line 35 the CMakeLists.txt specifies C++17.
set(CMAKE_CXX_STANDARD 17)
With the release of the CopperSpice 2.0 libraries you will need to modify line 35 of the CMakeLists.txt file to specify C++20.
set(CMAKE_CXX_STANDARD 20)