mirror of
https://gitlab.isc.org/isc-projects/kea
synced 2025-08-22 18:08:16 +00:00
34 lines
988 B
Plaintext
34 lines
988 B
Plaintext
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AC_DEFUN([AX_ISC_CPP20], [
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AC_MSG_CHECKING(c++20 support)
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# Save flags.
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CPPFLAGS_SAVED="${CPPFLAGS}"
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LIBS_SAVED="${LIBS}"
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# Provide -std=c++20 flag temporarily.
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CPPFLAGS="${CPPFLAGS} -std=c++20"
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# Simulate the definition of std::derived_from.
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AC_COMPILE_IFELSE(
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[AC_LANG_PROGRAM(
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[#include <concepts>
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template<class Derived, class Base>
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concept derived_from =
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std::is_base_of_v<Base, Derived> &&
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std::is_convertible_v<const volatile Derived*, const volatile Base*>;
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struct BaseClass {};
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struct DerivedClass : BaseClass {};
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],
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[static_assert(std::derived_from<BaseClass, DerivedClass> == false);
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static_assert(std::derived_from<DerivedClass, BaseClass> == true);]
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)],
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[AC_MSG_RESULT([yes])
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CPP20_SUPPORTED=true],
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[AC_MSG_RESULT([no])
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CPP20_SUPPORTED=false])
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# Restore flags.
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CPPFLAGS="${CPPFLAGS_SAVED}"
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])
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