Use builtin C++ feature tests to check availability of language features
Submitted by Christoph Hertzberg @chhtz
Assigned to Nobody
Link to original bugzilla bug (#1764)
Version: 3.5 (future version)
Description
A lot of the relatively complicated feature detection code could be simplified by using built-in feature-tests of C++, e.g.,
// Does the compiler support variadic templates?
#ifndef EIGEN_HAS_VARIADIC_TEMPLATES
#if EIGEN_MAX_CPP_VER>=11 && defined(__cpp_variadic_templates)
#define EIGEN_HAS_VARIADIC_TEMPLATES __cpp_variadic_templates
#else
#define EIGEN_HAS_VARIADIC_TEMPLATES 0
#endif
#endif This needs to be tested with older compiler however, and we either need to still add some extra tests, or just un-support compilers which do not support these feature-tests.
https://en.cppreference.com/w/cpp/feature_test