Question

我正在尝试创建一个服务器/客户端程序，客户端将文本“Hello World”发送到服务器，然后服务器将文本打印到终端。

客户端程序终止后服务器发疯并继续打印“Hello World”，直到我通过Ctrl-C终止服务器。有人可以帮我理解原因吗？

selectserver.c

#include <sys/types.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <netdb.h> 
#include <stdio.h>
#include <string.h> 


main()
{
    struct sockaddr_in serveraddr, clientaddr; 
    int clientaddrlen;
    int request_sock, sock[2], numsocks, maxsocks;
    char buf[12]; 
    int i, rc;
    fd_set fds, readfds;
    struct timeval timeout;

    numsocks = 0; maxsocks = 2;

    timeout.tv_sec = 5;
    timeout.tv_usec = 0;


    request_sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

    bzero((void *) &serveraddr, sizeof(serveraddr));
    serveraddr.sin_family = AF_INET; 
    serveraddr.sin_addr.s_addr = INADDR_ANY;
    serveraddr.sin_port = htons(2009);

    bind(request_sock, (struct sockaddr *)&serveraddr, sizeof serveraddr);

    listen(request_sock, SOMAXCONN);


    FD_ZERO(&fds);
    FD_SET(request_sock, &fds);


    for (;;) {
        readfds=fds;
        rc=select (FD_SETSIZE, &readfds, NULL, NULL, &timeout);
        if (rc<0)
            return -1;

        for (i = 0; i < FD_SETSIZE; i++)
            if (FD_ISSET (i, &readfds)) {
                if (i == request_sock) {
                    if(numsocks < maxsocks) {

                        sock[numsocks] = accept(request_sock,(struct sockaddr *)&clientaddr, (socklen_t *)&clientaddrlen);

                        FD_SET(sock[numsocks], &fds);
                        numsocks++;
                    } else {
                        printf("Ran out of space for sockets.\n");
                        return -1;
                    }
                } else {


                    read(i, buf,11);
                    buf[11] = '\0';
                    printf("From socket %d: %s\n",i,buf);

                }


            }

    } 

    close(request_sock);
}

selectclient.c

#include <netinet/in.h> 

#include <sys/socket.h>

#include <netdb.h> 

#include <stdio.h>

#include <string.h> 

#include <unistd.h>



main(int argc, char *argv[])

{



     struct sockaddr_in serveraddr;

     int sock;

     char buf[12]; 

    int i;





    sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);





    bzero((void *) &serveraddr, sizeof(serveraddr));





    serveraddr.sin_family = AF_INET;



    serveraddr.sin_addr.s_addr = inet_addr("192.168.1.3");





    serveraddr.sin_port = htons(2009);





    connect(sock, (struct sockaddr *)&serveraddr, sizeof serveraddr); 





    for(i=0; i<10; i++) {

        write(sock, "Hello World", 11);

        sleep(1);

    }



    close(sock);



}

Answer 1

   read(i, buf,11);
   buf[11] = '\0';

您忽略了read（）的返回码。如果为零，则对等体已断开连接，您必须关闭套接字。如果是正数，则是接收的字节数。所以第二行中的'11'应该是'count'或者你收到返回代码的变量被调用的任何内容。你不能假设你有11个字节。

客户端断开后服务器很奇怪

1 个答案: