Export methods

exporting.h

#pragma once

#ifdef _EXPORT
  #ifdef _MSC_VER
    #define DLL_API __declspec(dllexport)
  #elif defined __GNUC__
    #define DLL_API __attribute__((visibility("default")))
  #endif
#else
  #ifdef _MSC_VER
    #define DLL_API __declspec(dllimport)
  #elif defined __GNUC__
    #define DLL_API __attribute__((visibility("hidden")))
  #endif
#endif

usage.h

#include "exporting.h"

extern "C" {
    DLL_API void say_hello_dll();
}

// See https://github.com/onqtam/doctest