如何摆脱套接字程序中的for循环？

Question

int CreateSocket()
{
struct sockaddr_in server, client;  // creating a socket address structure: structure contains ip address and port number
WORD wVersionRequested;
WSADATA wsaData;
int len;
int iResult;

//int count = 0;

//u_long iMode = 1;


    printf("Initializing Winsock\n");


    wVersionRequested = MAKEWORD (1, 1);
    iResult =  WSAStartup (wVersionRequested, &wsaData);      
    if (iResult != NO_ERROR)
   printf("Error at WSAStartup()\n"); 


    // create socket
    sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (sock < 0)    {
        printf("Could not Create Socket\n");
        //return 0;
    }

    printf("Socket Created\n");  

//      iResult = ioctlsocket(sock, FIONBIO, &iMode);
//if (iResult != NO_ERROR)
//  printf("ioctlsocket failed with error: %ld\n", iResult);


    // create socket address of the server
    memset( &server, 0, sizeof(server));


    // IPv4 - connection
    server.sin_family = AF_INET;
    // accept connections from any ip adress
    server.sin_addr.s_addr = htonl(INADDR_ANY);
    // set port
    server.sin_port = htons(52428);


    //Binding between the socket and ip address
    if(bind (sock, (struct sockaddr *)&server, sizeof(server)) < 0)
    {
        printf("Bind failed with error code: %d", WSAGetLastError());
    }


    //Listen to incoming connections
    if(listen(sock, 10) == -1){
        printf("Listen failed with error code: %d", WSAGetLastError());
    }

    printf("Server has been successfully set up - Waiting for incoming connections");

    for(;;)   // accepting the connection continuously
    {
        len = sizeof(client);
        fd = accept(sock, (struct sockaddr*) &client, &len);

        if(fd < 0)
        {
            printf("Accept failed\n");
        }
        else
        {
        printf("\n Process incoming connection from (%s , %d)", inet_ntoa(client.sin_addr),ntohs(client.sin_port));
        break;
        }

    }

}
void main()
{
    int data;

double Task2ms_Raster, Task10ms_Raster, Task100ms_Raster ;


CreateSocket();

 Xcp_Initialize();

    while(1)
        {
            data = recv(fd, recv_data, 99, 0);
            if (data == SOCKET_ERROR) {
     printf("recv failed with error %d\n", WSAGetLastError());
     } else
            {
             pChunkData = &recv_data;
            chunkLen = sizeof(pChunkData);
            XcpIp_RxCallback ((uint16) chunkLen, (char*) pChunkData, (uint16) port);
            }


        }

}

上面是一个服务器套接字程序：我创建了一个套接字，用于接受带有 ip 地址和端口号的连接。我的程序继续接受连接，只要它接受连接，它就应该退出 for 循环。锄头使上述程序在接受连接时退出循环??
谁能帮帮我。

我修改了上面的代码并添加了主程序。接受来自客户端的连接后。然后我得到输出，因为 recv 失败并出现错误。控制将进入 while 循环并显示为 :recv failed with error 在主函数中。为什么会这样？？

Answer 1

使用break 语句。它可用于退出任何类型的循环。

或者，当然，使accept() 成为循环的条件：

while( (fd = accept(...)) >= 0)
{
}

在阅读代码时可以立即清楚地表明“啊，这是一个循环，只要我们能够接受传入的连接，它就会一直运行”。

当你将退出条件“埋”在里面并使用break时，它变得更难理解了。

Answer 2

你应该看看---->

while(1)

{

 //conditon for break
if(fd < 0)
    {
        printf("Accept failed\n");
        break;
    }

}

Answer 3

干得好，伙计。只需将break 放在其他部分即可。

for(;;)   // accepting the connection continuously
    {
        len  = sizeof(client);
    fd = accept(sock, (struct sockaddr*) &client, &len);

    if(fd < 0)
    {
        printf("Accept failed\n");
    }
    else
    {
    printf("\n Process incoming connection from (%s , %d)", inet_ntoa(client.sin_addr),ntohs(client.sin_port));
    break;

    }

}