A crazy libffi test.

test-ffi.cc

#include <ffi.h>
#include <iostream>

using namespace std;

class IInterface {
public:
	virtual void fn1(int a, int b) = 0;
	virtual void fn2(int a, int b) = 0;
	~IInterface() {}
};

class A : public IInterface
{
public:
	A(int c, int d) : c(c), d(d) {}
	virtual void fn1(int a, int b);
	virtual void fn2(int a, int b);
private:
	int c,d;
};

void A::fn1(int a, int b)
{
	cout << "fn1(" << a << ", " << b << ")" << endl;
	cout << "c=" << c << " d=" << d << endl;
}

void A::fn2(int a, int b)
{
	cout << "fn2(" << a << ", " << b << ")" << endl;
	cout << "c=" << c << " d=" << d << endl;
}

void call(void(**p)(void), IInterface *po)
{
	ffi_cif cif;
	ffi_type *args[3];
	void *values[3];
	int rc;
	int a=1, b=2;

	/* Initialize the argument info vectors */
	args[0] = &ffi_type_pointer;
	values[0] = &po;

	args[1] = &ffi_type_sint32;
	values[1] = &a;

	args[2] = &ffi_type_sint32;
	values[2] = &b;

	/* Initialize the cif */
	if (ffi_prep_cif(&cif, FFI_DEFAULT_ABI, 3,
				&ffi_type_void, args) == FFI_OK)
	{
		ffi_call(&cif, p[0], NULL, values);
		ffi_call(&cif, p[1], NULL, values);
	}
}

int main(void)
{
	A o(3,4);
	call(*reinterpret_cast<void(***)(void)>(dynamic_cast<IInterface*>(&o)), &o);

	return 0;
}