dlopen example

compile.sh

g++ -fPIC -c hello.cpp
g++ -shared -o hello.so hello.o

g++ main.cpp -ldl

hello.cpp

#include <iostream>

extern "C" int hello(){
	std::cout << "dicks dicks dicks!\n";
	return 42;
}

main.cpp

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

using namespace std;

int main(){
	void *handle = dlopen("./hello.so", RTLD_LAZY);
	if(!handle){
		cout << "Failed to open library hello.so\n";
		return 1;
	}
	
	cout << "Loading symbol...\n";
	typedef int (*hello_t)();
	
	dlerror();
	hello_t hello = (hello_t) dlsym(handle, "hello");
	const char *dlsym_error = dlerror();
	if(dlsym_error){
		cout << "Cannot load symbol hello\n";
		dlclose(handle);
		return 1;
	}
	
	cout << "Calling function...\n";
	int x = hello();
	cout << "Got: " << x << "\n";
	
	dlclose(handle);
	return 0;
}