Tutorial 1 for C++ modular application

app.cpp

#include <dlfcn.h>
#include <iostream>

#include "ModuleBase.hpp"

int main(int argc, char ** argv)
{
	if (argc == 1)
	{
		std::cerr << "Usage: " << argv[0] << " modules...\n";
		return 1;
	}
	
	for (int i = 1; i < argc; ++i)
	{
		void* shared_library = dlopen(argv[i], RTLD_LAZY);
		ModuleBase* (*loader)() = reinterpret_cast<ModuleBase* (*)()>(dlsym(shared_library, "loader"));
		ModuleBase* module;
		if (loader)
		{
			module = loader();
			module->run();
		} else
		{
			std::cerr << "Error while loading: " << argv[i] << "\n";
		}
	}
	return 0;
}

ModuleBase.hpp

#ifndef MODULE_BASE_HPP
#define MODULE_BASE_HPP

class ModuleBase
{
	public:
		virtual void run() = 0;
};

#endif

ModuleSoph.cpp

#include "ModuleBase.hpp"
#include <iostream>

class ModuleSoph :
	public ModuleBase
{
	public:
		void run()
		{
			std::cout << "Sophisticated module is running!\n";
		}
};

extern "C" ModuleBase* loader()
{
	ModuleBase* m = new ModuleSoph;
	return m;
}

ModuleStart.cpp

#include "ModuleBase.hpp"
#include <iostream>

class ModuleStart :
	public ModuleBase
{
	public:
		void run()
		{
			std::cout << "Start module is running!\n";
		}
};

extern "C" ModuleBase* loader()
{
	ModuleBase* m = new ModuleStart;
	return m;
}