编写DLL代码

新建工程

新建空项目工程

点击确定。然后右键项目选择新建项。

出现下图，选择头文件。

再次选择新建项，选中C++文件，将其改为MySocketClient.c，然后选择添加。

到这里，新建工程就完成了。

然后右键项目，选择属性 将配置类型改为动态库(.dll)

编写头文件MySocketClient.h

#ifndef _INC_MYSOCKETCLIENT_H_

#define _INC_MYSOCKETCLIENT_H_

#define Import_SSS

#ifdef Import_SSS

#define API _declspec(dllexport)

#else

#define API _declspec(dllimport)

#endif

#ifdef _cplusplus//extern"C" 来告诉编译器:这是一个用C写成的库文件，请用C的方式来链接它们。

extern "C" {

#endif // _cplusplus

API//导出函数，让外界调用。

int socketClient_Init(void **handle);

API

int socketClient_Send(void *handle, unsigned char *buf, int buflen);

API

int socketClient_Recv(void *handle, unsigned char *buf, int *buflen);

API

int socketClient_Destory(void *handle);

#ifdef _cplusplus

}

#endif // _cplusplus

#endif //_INC_MYSOCKETCLIENT_H_

编写MySocketClient.c

#define _CRT_SECURE_NO_WARNINGS

#include

#include

#include

#include "MySocketClient.h"

typedef struct _Sck_Handle

{

char version[16];

char ip[16];

int port;

unsigned char *p;

int len;

}Sck_Handle;//定义Handle的结构体。

int socketClient_Init(void **handle)

{

int ret = 0;

Sck_Handle *tmpHandle = NULL;

if (handle == NULL)

{

ret = -1;

printf("[socketClient_Init] err %d handle=NULL ", ret);

return ret;

}

tmpHandle = (Sck_Handle *)malloc(sizeof(Sck_Handle));

if (tmpHandle == NULL)

{

ret = -2;

printf("[socketClient_Init] err:%d malloc err ", ret);

}

memset(tmpHandle, 0, sizeof(Sck_Handle));//初始化结构体。

strcpy(tmpHandle->version, "1.0.0.1");

strcpy(tmpHandle->ip, "192.168.12.121");

tmpHandle->port = 11111;

*handle = tmpHandle;

return ret;

}

socket报文发送

//__declspec(dllexport)

int socketClient_Send(void *handle, unsigned char *buf, int buflen)

{

int ret = 0;

Sck_Handle *tmpHandle = NULL;

if (handle == NULL || buf == NULL || buflen <= 0)

{

ret = -2;

printf("func socketclient_send() err :%d (handle == NULL || buf==NULL || buflen <=0 ) ", ret);

return ret;

}

tmpHandle = (Sck_Handle *)handle;

tmpHandle->len = buflen;

tmpHandle->p = (unsigned char *)malloc(buflen);

if (tmpHandle->p == NULL)

{

ret = -2;

printf("func socketclient_send() err :%d malloc len:%d ", ret, buflen);

return ret;

}

memcpy(tmpHandle->p, buf, buflen); //数据的缓存到内存

printf("接收到发送数据是%s ", tmpHandle->p);

return ret;

}

socket报文接受

//__declspec(dllexport)

int socketClient_Recv(void *handle, unsigned char *buf, int *buflen)

{

int ret = 0;

Sck_Handle *tmpHandle = NULL;

if (handle == NULL || buf == NULL || buflen == NULL)

{

ret = -2;

printf("func socketclient_recv() err :%d (handle == NULL || buf==NULL || buflen==NULL ) ", ret);

return ret;

}

tmpHandle = (Sck_Handle *)handle;

memcpy(buf, tmpHandle->p, tmpHandle->len);

*buflen = tmpHandle->len; //间接赋值 告诉调用者 收到的数据的长度

printf("数据长度是%d ", tmpHandle->len);

return ret;

}

socket环境释放

//__declspec(dllexport)

int socketClient_Destory(void *handle)

{

int ret = 0;

Sck_Handle *tmpHandle = NULL;

if (handle == NULL)

{

return -1;

}

tmpHandle = (Sck_Handle *)handle;

if (tmpHandle->p != NULL)

{

free(tmpHandle->p); //释放结构体 成员域的 指针所指向的内存空间

}

free(tmpHandle); //释放结构体内存

return 0;

}

然后右键编译工程。在Debug文件夹下面就可以看到生成的dll

动态调用

动态调用，使用LoadLibrary方法加载dll。

新建C++控制台应用程序

新建完成后，将编译好的dll文件、lib文件和h文件放到工程下面。

右键项目属性，将字符集改为使用多字节字符集。

下面是调用dll的代码。

#define _CRT_SECURE_NO_WARNINGS

#include

#include

#include

using namespace std;

//定义指针函数

typedef int(*SOCLETCLIENT_INIT)(void **handle);

typedef int(*SOCKETCLIENT_SEND)(void *handle, unsigned char *buf, int buflen);

typedef int(*SOCKETCLIENT_RECV)(void *handle, unsigned char *buf, int *buflen);

typedef int(*SOCKETCLIENT_DESTORY)(void *handle);

int main()

{

HINSTANCE hInstance;

hInstance = LoadLibrary("MySocketClient.dll");

SOCLETCLIENT_INIT socketClient_Init= (SOCLETCLIENT_INIT)GetProcAddress(hInstance, "socketClient_Init");

SOCKETCLIENT_SEND socketClient_Send=(SOCKETCLIENT_SEND)GetProcAddress(hInstance, "socketClient_Send");;

SOCKETCLIENT_RECV socketClient_Recv= (SOCKETCLIENT_RECV)GetProcAddress(hInstance, "socketClient_Recv");;

SOCKETCLIENT_DESTORY socketClient_Destory= (SOCKETCLIENT_DESTORY)GetProcAddress(hInstance, "socketClient_Destory");;

unsigned char buf[1024];

int buflen;

unsigned char out[1024];

int outlen;

void *handle = NULL;

int ret = 0;

strcpy((char *)buf, "aaaaAAAAAFFffffffdddddddd");

buflen = 9;

//客户端初始化 获取handle上下

ret = socketClient_Init(&handle /*out*/);

if (ret != 0)

{

printf("func socketclient_init() err:%d ", ret);

goto End;

}

//客户端发报文

ret = socketClient_Send(handle /*in*/, buf /*in*/, buflen /*in*/);

if (ret != 0)

{

printf("func socketclient_send() err:%d ", ret);

goto End;

}

//客户端收报文

ret = socketClient_Recv(handle /*in*/, out /*in*/, &outlen/*in out*/);

if (ret != 0)

{

printf("func socketclient_recv() err:%d ", ret);

goto End;

}

printf("接收到的数据长度是%d ",outlen);

End:

//客户端释放资源

ret = socketClient_Destory(handle/*in*/);

if (hInstance != NULL)

{

FreeLibrary(hInstance);

hInstance = NULL;

}

printf("hello...");

system("pause");

return 0;

}

使用

#define _CRT_SECURE_NO_WARNINGS

#include

#include

#include

using namespace std;

#pragma comment(lib,"MySocketClient.lib")

extern "C"

{

int socketClient_Init(void **handle);

int socketClient_Send(void *handle, unsigned char *buf, int buflen);

int socketClient_Recv(void *handle, unsigned char *buf, int *buflen);

int socketClient_Destory(void *handle);

}

int main()

{

unsigned char buf[1024];

int buflen;

unsigned char out[1024];

int outlen;

void *handle = NULL;

int ret = 0;

strcpy((char *)buf, "aaaaAAAAAFFffffffdddddddd");

buflen = 9;

//客户端初始化 获取handle上下

ret = socketClient_Init(&handle /*out*/);

if (ret != 0)

{

printf("func socketclient_init() err:%d ", ret);

goto End;

}

//客户端发报文

ret = socketClient_Send(handle /*in*/, buf /*in*/, buflen /*in*/);

if (ret != 0)

{

printf("func socketclient_send() err:%d ", ret);

goto End;

}

//客户端收报文

ret = socketClient_Recv(handle /*in*/, out /*in*/, &outlen/*in out*/);

if (ret != 0)

{

printf("func socketclient_recv() err:%d ", ret);

goto End;

}

printf("接收到的数据长度是%d ", outlen);

End:

//客户端释放资源

ret = socketClient_Destory(handle/*in*/);

printf("hello...");

system("pause");

return 0;

}

静态调用

静态调用，使用lib文件调用

#define _CRT_SECURE_NO_WARNINGS

#include

#include

#include

using namespace std;

#pragma comment(lib,"MySocketClient.lib")

extern "C"

{

int socketClient_Init(void **handle);

int socketClient_Send(void *handle, unsigned char *buf, int buflen);

int socketClient_Recv(void *handle, unsigned char *buf, int *buflen);

int socketClient_Destory(void *handle);

}

int main()

{

unsigned char buf[1024];

int buflen;

unsigned char out[1024];

int outlen;

void *handle = NULL;

int ret = 0;

strcpy((char *)buf, "aaaaAAAAAFFffffffdddddddd");

buflen = 9;

//客户端初始化 获取handle上下

ret = socketClient_Init(&handle /*out*/);

if (ret != 0)

{

printf("func socketclient_init() err:%d ", ret);

goto End;

}

//客户端发报文

ret = socketClient_Send(handle /*in*/, buf /*in*/, buflen /*in*/);

if (ret != 0)

{

printf("func socketclient_send() err:%d ", ret);

goto End;

}

//客户端收报文

ret = socketClient_Recv(handle /*in*/, out /*in*/, &outlen/*in out*/);

if (ret != 0)

{

printf("func socketclient_recv() err:%d ", ret);

goto End;

}

printf("接收到的数据长度是%d ", outlen);

End:

//客户端释放资源

ret = socketClient_Destory(handle/*in*/);

printf("hello...");

system("pause");

return 0;

}

运行结果：