std_cxx20 Namespace Reference

Namespaces
namespace	ranges

Classes
struct	type_identity

Typedefs
template<class T >
using	type_identity_t = typename type_identity< T >::type

Detailed Description

deal.II currently only requires a C++14-conforming compiler, but there are a number of functions and classes from the C++20 standard that are easy to provide also in case the compiler only supports C++14. These are collected in the current namespace.

One example is the std::ranges::iota_view class that was introduced to C++ starting with the C++20 standard. It is used as the return type for the ReferenceCell::face_indices(), ReferenceCell::vertex_indices(), and FEValuesBase::quadrature_point_indices() functions, among others, to support range-based for loops (see deal.II and Modern C++ standards for examples of range-based for loops, as well as the documentation of the functions mentioned above).

There are other small additions in this namespace that allow us to use C++20 features at this point already, even though we don't require a C++20-compliant compiler.

Note

If the compiler in use actually does support C++20, then the contents of this namespace are simply imported classes and functions from namespace std. That is, we fall back to what the compiler provides, rather than our own implementations.

Typedef Documentation

type_identity_t

template<class T >

using std_cxx20::type_identity_t = typedef typename type_identity<T>::type

Definition at line 96 of file type_traits.h.