dll-实例

Source.def

LIBRARY exportDll2
EXPORTS
    Add

exportDll2.h

// The following ifdef block is the standard way of creating macros which make exporting
// from a DLL simpler. All files within this DLL are compiled with the EXPORTDLL2_EXPORTS
// symbol defined on the command line. This symbol should not be defined on any project
// that uses this DLL. This way any other project whose source files include this file see
// EXPORTDLL2_API functions as being imported from a DLL, whereas this DLL sees symbols
// defined with this macro as being exported.
#ifdef EXPORTDLL2_EXPORTS
#define EXPORTDLL2_API __declspec(dllexport)
#else
#define EXPORTDLL2_API __declspec(dllimport)
#endif



//EXPORTDLL2_API int fnexportDll2(void);
int Add(int a, int b);

 exportDll2.cpp

// exportDll2.cpp : Defines the exported functions for the DLL.
//

#include "pch.h"
#include "framework.h"
#include "exportDll2.h"



// This is an example of an exported function.
//EXPORTDLL2_API int fnexportDll2(void)
//{
//    return 0;
//}

int Add(int a, int b)
{
    return a+b;
}

main.cpp

#include<stdio.h>
#include<windows.h>
//注意dll文件名和后缀名不区分大小写
typedef int (*FUNC)(int a, int b);
//引用库的时候必须包含两个文件

//#include"../exportDll2/exportDll2.h"//1.引用头文件
//#pragma comment(dll,"../Debug/EXPORTDLL2.dll")//2.引用库文件
int main()
{
    HINSTANCE hDll = ::LoadLibrary("eXPORTDLL2.dll");
    {
        int result;
        // 取得Add()函数的地址
        //FUNC mAdd = (FUNC)::GetProcAddress(hDll, "?Add@@YAHHH@Z");
        FUNC mAdd = (FUNC)::GetProcAddress(hDll, "Add");
        if (mAdd != NULL)
        {
            result = mAdd(1, 2);
            printf("%d", result);

        }
        else
            printf("Error");
        // 卸载DLL库
        ::FreeLibrary(hDll);
    }
    /*int result;
    result = Add(1, 2);
    printf("%d", result);*/
    return 0;
}

 注：dll如果以c++方式导出，用的时候以c使用，编译器对函数的修饰不一样，就会出错，提示无法解析外部符号

将exportDll.h改为

#ifdef EXPORTDLL2_EXPORTS
#define EXPORTDLL2_API __declspec(dllexport)
#else
#define EXPORTDLL2_API __declspec(dllimport)
#endif



#ifdef __cplusplus
extern "C" {
#endif

    //EXPORTDLL2_API int fnexportDll2(void);
    int Add(int a, int b);

#ifdef __cplusplus

}
#endif