c++ - 绑定(bind)失败 : Bad file descriptor

Question

我是套接字编程的新手，在这里我尝试设置一个简单的服务器套接字并监听它。这是我的代码。

 int server_socket, client_socket, sent;
    size_t len;
    struct sockaddr_in server, client;
    char msg[] = "Hello to the world of socket programming";
    server_socket == socket(AF_INET, SOCK_STREAM, 0);

    if(server_socket == -1){
        perror("Socket creation failed: ");
        exit(-1);
    }

    //define server
    server.sin_family = AF_INET;
    server.sin_port = htons(10000);
    server.sin_addr.s_addr = INADDR_ANY;
    memset(&server.sin_zero, '\0', 8);


    len = sizeof(struct sockaddr_in);

    if((bind(server_socket, (struct sockaddr*)&server, len)) == -1){
        perror("Bind failed: ");
        exit(-1);
    }

    if(listen(server_socket, 5) == -1){
        perror("Listen failed: ");
        exit(-1);
    }

    while(true){

        if((client_socket = accept(server_socket, (struct sockaddr *)&client, (socklen_t *)&len)) == -1){

            perror("Accept failed: ");
            exit(-1);
        }

        sent = send(client_socket, msg, strlen(msg), 0);

        printf("Sent %d byte to client: %s\n", sent, inet_ntoa(client.sin_addr));

        close(client_socket);

    }

我不断得到

Bind Failed : Bad file descriptor

但是我的文件描述符完全符合 beej 指南。有帮助吗？

Answer 1

这是你的问题:

server_socket == socket(AF_INET, SOCK_STREAM, 0);

您没有为 server_socket 分配任何内容。您正在将它与 socket 的返回值进行比较。你需要这样做:

server_socket = socket(AF_INET, SOCK_STREAM, 0);

由于您正在监听 TCP 套接字，因此您还需要这样做:

int option=1;
setsockopt(sock,SOL_SOCKET,SO_REUSEADDR,(char *)&option,sizeof(option));

这将防止应用程序在短时间内被终止并重新启动时出现“地址已在使用”错误。