Quelle  unreachable.hxx

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#ifndef INCLUDED_O3TL_UNREACHABLE_HXX
#define INCLUDED_O3TL_UNREACHABLE_HXX

#include <sal/config.h>

#include <cassert>
#include <utility>

// An approximation of C++23 std::unreachable
// (<http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p0627r6.pdf> "Function to mark
// unreachable code").

#if defined __cpp_lib_unreachable

#define O3TL_UNREACHABLE (::std::unreachable())

#else

// This fallback implementation is inspired by LLVM's LLVM_BUILTIN_UNREACHABLE
// (llvm/include/llvm/Support/Compiler.h).

#if defined _MSC_VER
#define O3TL_UNREACHABLE_detail __assume(false)
#else // assuming Clang or GCC with support for:
#define O3TL_UNREACHABLE_detail __builtin_unreachable()
#endif

#define O3TL_UNREACHABLE                                                                           \
    do                                                                                             \
    {                                                                                              \
        assert(false);                                                                             \
        O3TL_UNREACHABLE_detail;                                                                   \
    } while (false)

#endif

#endif

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