C Socket初探 - 加入多线程支持,限制最大接入客户端个数

先上一些多线程需要使用的函数定义:

DWORD WINAPI ProcessClientRequests(LPVOID lpParam)  //新线程将会执行的函数定义
{
      return 0;
}

HANDLE handler=CreateThread(NULL, 0, ProcessClientRequests, &clientsocket, 0, NULL);   //这里比较简单,&clientsocket是个指针,是从主线程传入新线程的参数


WaitForMultipleObjects(MAXCLIENTS, threads, TRUE, INFINITE);  //用来阻塞主线程,直到所有创建的子线程都完成任务为止,才继续执行后面的代码

for(int i=0;i<MAXCLIENTS; i++)
{
    CloseHandle(threads[i]);       //创建的每个子线程的HANDLE都会被保存在HANDLE数组中,这个函数用于关闭各个handle所对应的线程空间
}

 

先附上C Socket初探这篇文章的url

改造开始,客户端程序没有任何改动,因此此处略(请看C Socket初探中代码所示)

 

服务器端程序

主线程代码如下:

#define MAXCLIENTS 3           //宏定义,最多3个客户端连接

int main()
{
    WSADATA wsaData;
    WSAStartup(MAKEWORD(2, 2), &wsaData);
    HANDLE threads[MAXCLIENTS];

    SOCKET s=socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);

    sockaddr_in sockaddr;
    sockaddr.sin_family=PF_INET;
    sockaddr.sin_addr.S_un.S_addr=inet_addr("127.0.0.1");
    sockaddr.sin_port=htons(9000);
    bind(s, (SOCKADDR*)&sockaddr, sizeof(SOCKADDR));

    listen(s, 1);

    printf("listening on port [%d].\n", 9000);

    int existingClientCount=0;
    while(TRUE)
    {
        SOCKADDR clientAddr;
        int size=sizeof(SOCKADDR);

        SOCKET clientsocket;
        clientsocket=accept(s, &clientAddr, &size);
        printf("***SYS***    New client touched.\n");

        if(existingClientCount<MAXCLIENTS)       //判断是否已经超出最大连接数了
        {
            threads[existingClientCount++]=CreateThread(NULL, 0, ProcessClientRequests, &clientsocket, 0, NULL);  //启动新线程,并且将socket传入
        }
        else
        {
            char* msg="Exceeded Max incoming requests, will refused this connect!\r\n";
            send(clientsocket, msg, strlen(msg)+sizeof(char), NULL);       //发送拒绝连接消息给客户端
            printf("***SYS***    REFUSED.\n");
            closesocket(clientsocket);                                     //释放资源
break;
} } printf(
"Maximize clients occurred for d%.\r\n", MAXCLIENTS); WaitForMultipleObjects(MAXCLIENTS, threads, TRUE, INFINITE); //等待所有子线程,直到完成为止 closesocket(s); for(int i=0;i<MAXCLIENTS; i++) { CloseHandle(threads[i]); //清理线程资源 } WSACleanup(); printf("Cleared all.\r\n"); getchar(); exit(0); }

子线程函数定义

DWORD WINAPI ProcessClientRequests(LPVOID lpParam)
{
    SOCKET* clientsocket=(SOCKET*)lpParam;  //这里需要强制转换,注意:指针类型的

    char* msg="Hello, my client.\r\n";
    send(*clientsocket, msg, strlen(msg)+sizeof(char), NULL);
    printf("***SYS***    HELLO.\n");

    while(TRUE)
    {
        char buffer[MAXBYTE]={0};
        recv(*clientsocket, buffer, MAXBYTE, NULL);
        if(strcmp(buffer, "exit")==0)
        {
            char* msg_bye="Bye.\r\n";
            send(*clientsocket, msg_bye, strlen(msg_bye)+sizeof(char), NULL);
            break;
        }
        printf("***Client***    %s\n", buffer);
    }
    
    closesocket(*clientsocket);

    return 0;
}

 

 

 

运行效果图:

 

 

 

posted @ 2013-07-28 16:06  McKay  阅读(8855)  评论(6编辑  收藏  举报