win32的hook

int myprintf (
	const char *format,
	...
	)
{
	return 0;
}

int main()
{
	printf("a\n");

	char * target_function = (char *)&printf;

	DWORD old_target_function_protect = 0;
	BOOL succeeded = ::VirtualProtect(reinterpret_cast<void*>(target_function),
		32,
		PAGE_EXECUTE_READWRITE,
		&old_target_function_protect);

	if (!succeeded) {
		return -1;
	}

	*target_function = 0xE9;
	char * newfuc = (char*)&myprintf;
	int offset = newfuc - target_function - 5;
	memcpy(target_function + 1, &offset, 4);

	succeeded = ::VirtualProtect(reinterpret_cast<void*>(target_function),
		32,
		old_target_function_protect,
		&old_target_function_protect);

	printf("aa\n");

	return 0;
}