C++怎么实现一个跨平台的动态库加载器_C++库管理与跨平台动态库实现

#include <string>
#ifdef _WIN32
  #include <windows.h>
  using lib_handle = HMODULE;
#else
  #include <dlfcn.h>
  using lib_handle = void*;
#endif

class DynamicLib {
public:
  explicit DynamicLib(const std::string& path) : handle_(nullptr), path_(path) {}

  ~DynamicLib() { unload(); }

  bool load() {
    if (handle_) return true;

#ifdef _WIN32
    handle_ = LoadLibrary(path_.c_str());
#else
    handle_ = dlopen(path_.c_str(), RTLD_LAZY);
#endif

    return handle_ != nullptr;
  }

  void unload() {
    if (handle_) {
#ifdef _WIN32
      FreeLibrary(static_cast<HMODULE>(handle_));
#else
      dlclose(handle_);
#endif
      handle_ = nullptr;
    }
  }

  template<typename FuncType>
  FuncType get_function(const std::string& name) {
#ifdef _WIN32
    auto ptr = GetProcAddress(static_cast<HMODULE>(handle_), name.c_str());
    return reinterpret_cast<FuncType>(ptr);
#else
    auto ptr = dlsym(handle_, name.c_str());
    return reinterpret_cast<FuncType>(ptr);
#endif
  }

  bool is_loaded() const { return handle_ != nullptr; }

private:
  lib_handle handle_;
  std::string path_;
};

// math_plugin.cpp
extern "C" {
  __declspec(dllexport) double add(double a, double b) {
    return a + b;
  }
}