Create DLL in VC and export global variables, functions and Classes

ArticleDirectory

• 1. Create DLL
• 2. Test the created DLL

1. Create dll1. create a new Win32 Empty Project mathlib in VC; 2. Add the pre-compiled header file stdafx. h and define the Import and Export Control symbols:

 
1:// Stdafx. h
 
 
2: # pragma once
 
 
3: # define mathlib_export
 
3. Add the header file mathlib. H that contains the global variables, functions, and classes to be exported:
1:// Mathlib. h
 
 
2: # pragma once
 
 
3:
 
 
4: # ifdef mathlib_export
 
 
5: # define mathlibapi _ declspec (dllexport)
 
6 :#Else
 
 
7: # define mathlibapi _ declspec (dllimport)
 
 
8: # endif
 
 
9:
 
 
10:// Macro
 
11: # define PI 3.14149
 
 
12:
 
 
13:// Global variable
 
 
14:ExternMathlibapiIntGlobalvariable;
 
 
15:
 
16:// Function
 
 
17: mathlibapiIntAdd (IntA,IntB );
 
 
18:
 
 
19:// Class
 
20:ClassMathlibapi math
 
 
21 :{
 
 
22:Public:
 
 
23:IntMultiply (IntA,IntB );
 
24 :};
 
4. Add the exported element implementation file mathlib. cpp.
 
1:// Mathlib. cpp
 
 
2: # include"Stdafx. h"
 
 
3: # include"Mathlib. h"
 
4:
 
 
5:IntGlobalvariable = 100;
 
 
6:
 
 
7:IntAdd (IntA,IntB)
 
 
8 :{
 
9:ReturnA + B;
 
 
10 :}
 
 
11:
 
 
12:IntMath: multiply (IntA,IntB)
 
 
13 :{
 
14:ReturnA * B;
 
 
15 :}
 
2. Test the created DLL
 
TestCode:
 
 
1: # include"Stdafx. h"
 
 
2: # include <iostream>
 
3:Using NamespaceSTD;
 
 
4:
 
 
5: # include"../Mathlib. h"
 
 
6: # pragma comment (Lib ,"../Debug/mathlib. Lib")
 
7:
 
 
8:Int_ Tmain (IntArgc, _ tchar * argv [])
 
 
9 :{
 
 
10: cout <"Pi ="<PI <Endl;
 
 
11:
 
12: cout <"Globalvariable ="<Globalvariable <Endl;
 
 
13:
 
 
14:IntA = 20, B = 30;
 
 
15: cout <"A ="<A <","<"B ="<B <Endl;
 
16: cout <"A + B ="<Add (a, B) <Endl;
 
 
17:
 
 
18: Math math;
 
 
19: cout <"A * B ="<Math. Multiply (a, B) <Endl;
 
 
20:
 
21:Return0;
 
 
22 :}