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To make this project a little useful for our learning
process, we will use two types of functions: those that are used
internally by the DLL only, and those that can be used by external
functions, that is, the other programs that will need this DLL.
- To create functions that are used internally by the DLL, change the
program as follows:
// ExoDLL.cpp : Defines the entry point for the DLL application.
//
#include "stdafx.h"
// This function is used to calculate the total area of a parallelepid rectangle
double BoxArea(double L, double H, double W);
// This function is used to calculate the volume of a parallelepid rectangle
double BoxVolume(double L, double H, double W);
BOOL APIENTRY DllMain( HANDLE hModule,
DWORD ul_reason_for_call,
LPVOID lpReserved
)
{
return TRUE;
}
double BoxArea(double L, double H, double W)
{
return 2 * ((L*H) + (L*W) + (H*W));
}
double BoxVolume(double L, double H, double W)
{
return L * H * W;
} |
- Notice that the BoxArea() and the BoxVolume() functions are declared
and defined just like any other function we know already.
To declare
and define a function that can be used outside of the DLL, that is, by a
function that uses the DLL, change the file as follows:
// ExoDLL.cpp : Defines the entry point for the DLL application.
//
#include "stdafx.h"
// This function is used to calculate the total area of a parallelepiped rectangle
double BoxArea(double L, double H, double W);
// This function is used to calculate the volume of a parallelepiped rectangle
double BoxVolume(double L, double H, double W);
// This function is used to get the dimensions of a rectangular parallelepiped
// calculate the area and volume, then pass the calculated values to the
// function that called it.
extern "C" __declspec(dllexport)void BoxProperties(double Length, double Height,
double Width, double& Area, double& Volume);
BOOL APIENTRY DllMain( HANDLE hModule,
DWORD ul_reason_for_call,
LPVOID lpReserved
)
{
return TRUE;
}
double BoxArea(double L, double H, double W)
{
return 2 * ((L*H) + (L*W) + (H*W));
}
double BoxVolume(double L, double H, double W)
{
return L * H * W;
}
void BoxProperties(double L, double H, double W, double& A, double& V)
{
A = BoxArea(L, H, W);
V = BoxVolume(L, H, W);
} |
- To save the project, on the main menu, click File -> Save All.
- To create the DLL, on the main menu, click Build -> Build
ExoDLL.dll. At the end, you should receive ExoDLL.dll - 0 error(s), 0 warning(s)
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