Dynamic Link Library function export - c++

Question

First the main.h file -
main.h
#ifndef __MAIN_H__
#define __MAIN_H__
#include <iostream>
#ifndef _BUILD_DLL
#define XXX_API __declspec(dllexport)
#else
#define XXX_API __declspec(dllimport)
#endif
#include "device.h"
// Core functions
namespace xxx
{
XXX_API void createDevice(int w, int h);
}
#endif // __MAIN_H__
main.cpp
#define _BUILD_DLL
namespace xxx
{
XXX_API void createDevice(int w, int h)
{
Device dev;
dev.createDevice(w, h);
}
}
device.h
#ifndef __DEVICE_H__
#define __DEVICE_H__
namespace xxx
{
class Device
{
public:
Device();
virtual ~Device();
XXX_API void createDevice(int width, int height);
}; // end of class
} // end of namespace
#endif
device.cpp
#include "main.h"
namespace xxx
{
Device::Device()
{
}
Device::~Device()
{
}
XXX_API void Device::createDevice(int width, int height)
{
std::cout << "Width: " << width << std::endl;
std::cout << "height: " << height << std::endl;
}
} // end of namespace
This are the files that create the dll and library.
And here is the test.cpp that creates the application which calls that lib functions-
#include "main.h"
int main()
{
xxx::createDevice(800, 600);
std::cout << "Press the ENTER key to exit.";
std::cin.ignore(std::cin.rdbuf()->in_avail() + 1);
return 0;
}
As you can see I am calling createDevice(int, int) to create the device. What I want to know is how do I export the dll calls so that I can get a pointer to that device to call its member function from test.cpp. like this -
#include "main.h"
int main()
{
xxx::Device* dev = createDevice(800, 600);
std::cout << "Press the ENTER key to exit.";
std::cin.ignore(std::cin.rdbuf()->in_avail() + 1);
return 0;
}
Thanks in advance

Answer 1

Change createDevice to this
XXX_API Device* createDevice(int w, int h)
{
Device* dev = new Device();
dev->createDevice(w, h);
return dev;
}
Presumably you should to add a destroyDevice function to free the memory.