Linker error with Catch and Clang/LLVM on Windows

Question

I have a linker problem with the code below. It works with the Visual Studio 2015 compiler, but not with Clang/LLVM in Visual Studio. I have tried may different variations (some below), all work fine. It seems to be the specific combination of the static constexpr numeric_limits<double> and REQUIRE.

// quicktest.cpp

#include <limits>
#include <iostream>
#define CATCH_CONFIG_MAIN  // This tells Catch to provide a main() - only do this in one cpp file
#include <catch.hpp>

struct X {
    static constexpr double min = std::numeric_limits<double>::min();
    static constexpr int min_int = std::numeric_limits<int>::min();
};

SCENARIO("blah")
{
        static const double my_min = X::min;                // works
        std::cout << (5 > X::min) << std::endl;             // works
        REQUIRE(5 > my_min);                                // works
        REQUIRE(5 > X::min_int);                            // works (int)
        REQUIRE(5 > std::numeric_limits<double>::min());    // works

        //REQUIRE(5 > X::min);                              // lnk2019

}

//int main()
//{
//    std::cout << (X::min < 5) << std::endl; // works
//  return 0;
//}

The exact error message with the last REQUIRE commented in is: Error LNK2019 unresolved external symbol "public: static double const X::min" (?min@X@@2NB) referenced in function "intvoid __cdecl anonymous namespace'::dynamic initializer for 'autoRegistrar11''(void)'::1'::dtor$2" (?dtor$2@?0???__EautoRegistrar11@?A@@YAXXZ@4HA) quicktest ...\quicktest\quicktest.obj 1

Luckily, it is simple to work around, but I was wondering what could be the exact reason for the problem. Actually, I have no idea, whether it is originating in catch or in the compiler or whatever. Any idea anyone?

Linker error with Catch and Clang/LLVM on Windows

0 Answers0