Write C-language DLLs in VS2008 environment and downgrade in C + + and C # projects (reprint)

1. Writing DLLs

A) file-open-New project--win32, right Win32 project, fill in the project name, click "Next",

Application type selection: "DLL (D)", additional option: Empty item (E), then finish.

b) Write the header file (edrlib.h):

#ifdef __cplusplus
#define EXPORT extern "C" __declspec (dllexport)
#else
#define EXPORT __declspec (dllexport)
#endif

EXPORT void Edrcentertexta ();
EXPORT void Edrcentertextw ();
EXPORT int Inccounter ();
#ifdef UNICODE
#define Edrcentertext EDRCENTERTEXTW
#else
#define Edrcentertext Edrcentertexta
#endif

Annotations:

I. Define the __cplusplus representation to be called in a C + + program.

Ii.__declspec (dllexport) represents the way a function is called, which represents the default way to invoke a VS2008 project property. Change method:

Right-click the project-Properties--Configuration Properties--c/c++--Advanced, change the right "calling convention".

c) Write DLL file (edrlib.cpp):

#include "Windows.h"
#include "Edrlib.h"
counter for all applications that call the DLL to share
#pragma data_seg ("shared")
int counter=0;
#pragma COMMENT (linker, "/SECTION:SHARED,RWS")

int WINAPI DllMain (_in_ HANDLE _hdllhandle, _in_ DWORD _reason, _in_opt_ lpvoid _reserved)
{
return TRUE;
}

EXPORT void Edrcentertexta ()
{
MessageBox (Null,text ("Call DLL Function!") "), TEXT (" Assic version "), MB_OK);

}
EXPORT void Edrcentertextw ()
{
MessageBox (Null,text ("Call DLL Function!") "), TEXT (" Unicode Version "), MB_OK);

}

EXPORT int Inccounter ()
{
return ++counter;
}  

c) Compile the build DLL.

2. Calling DLL

Method One,

1. Create a new Win32 application empty project.

2. Copy the generated DLL, lib 2 files to the new directory.

3. Add Import Library: Tools--Project and Solution--vc++ directory, select "Library file" under "Show Directory Below" to add the Lib directory.

4. Header files: edrlib.h (as in writing DLLs)

5. Source file: Main.c

/* #define  cplusplus*/ //c++ call mode    
# include  "Windows.h"    
#include   "Edrlib.h"    
#pragma   Comment (lib, "Edrlib.lib")    
   
Int winapi winmain (__in  hinstance hinstance, __in_opt hinstance hprevinstance, __in_opt lpstr  lpcmdline, __in int nshowcmd )    
{   
   
     tchar buf[32];   
    wsprintf (buf,l "now,counter=%i", Inccounter ());    
    messagebox (null,buf,l "--", MB_OK);    
    edrcentertext ();    
    return 0;    
}  

Explain:
Can be annotated #pragma comment (lib, "TestDLL2.lib") this, but must set up the link library, method:

Right-click the project--Properties--Configuration Properties--linker--input--Additional dependencies: Edrlib.lib

6. Run the test successfully.

"The above content is transferred from: Http://blog.csdn.net/breezes2008/archive/2010/02/25/5326861.aspx"

3. Calling DLLs in C #

This example uses a C program to create a DLL, which is called from a C # program in the next example.

cmdll.c//Compile with:/ldint __declspec (dllexport) samplemethod (int i) {return i*10;}

If it is a Web project, copy the DLL to the bin directory.

If it is a desktop program, copy the DLL to the executable line file directory.

Reference code:

Using system;using System.runtime.interopservices;public class MainClass{[DllImport ("Cmdll.dll")] public static extern int SampleMethod (int x);   static void Main () {Console.WriteLine ("SampleMethod () returns {0}.", SampleMethod (5)); }}

from:http://apps.hi.baidu.com/share/detail/33471191

Write C-language DLLs in VS2008 environment and downgrade in C + + and C # projects (reprint)