Running main on an hpx thread

run_main_on_hpx.cpp

#include <hpx/hpx.hpp>
#include <hpx/hpx_init.hpp>

#include <stdlib.h>

int __argc = 0;
char** __argv = nullptr;

void set_argc_argv(int argc, char* argv[], char* env[])
{
    __argc = argc;
    __argv = argv;
}

__attribute__((section(".preinit_array")))
    void (*set_global_argc_argv)(int, char*[], char*[]) = &set_argc_argv;

int main(int argc, char* argv[]);

struct manage_global_runtime {
	manage_global_runtime() {
		std::cout << "calling from struct" << std::endl;
		hpx::init(main, __argc, __argv);
		std::cout << "back in struct" << std::endl;
		exit(1);
	}
};

manage_global_runtime init;

int universal_ans(){
	return 42;
}

int main(int argc, char* argv[])
{
	std::cout << "Hello World!" << std::endl;
	hpx::future<int> f = hpx::async(universal_ans);
	int ans = f.get();
	std::cout << ans << std::endl;
	return hpx::finalize();
}