Winsock 服务器消息未显示在客户端终端上

Question

我创建了一个简单的 TCP 服务器，监听 8080 端口，一旦建立连接，它就会向客户端发送一条消息。这是代码。

#include <iostream>
#include <winsock2.h>
#pragma comment(lib, "ws2_32.lib")
#pragma warning(disable:4996) 

int main(int argc, char* argv[]) {
    WSADATA wsa;
    SOCKET s, new_socket;
    int c;
    int ret;
    struct sockaddr_in server, client;
    char* message = "Thank you for connecting to us but i got to go\n";

    if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0) {
        printf("Failed to initialize Winsock : %d", WSAGetLastError());
        return 1;
    }



    s = socket(AF_INET, SOCK_STREAM, 0);
    if (s == INVALID_SOCKET) {
        printf("Error creating socket : %d", WSAGetLastError());

    }


    server.sin_family = AF_INET;
    server.sin_port = htons(8080);
    server.sin_addr.s_addr = INADDR_ANY;


    if (bind(s, (struct sockaddr*)&server, sizeof(server)) == SOCKET_ERROR) {
        printf("Error binding socket : %d\n", WSAGetLastError());
        exit(EXIT_FAILURE);
    }

    listen(s, 3);

    puts("Listening for incoming connection\n");
    c = sizeof(struct sockaddr_in);
    while (new_socket = accept(s, (struct sockaddr*)&client, &c) != INVALID_SOCKET) {
        puts("Connection established\n");
        send(new_socket, message, strlen(message), 0);
    }

    if (new_socket == INVALID_SOCKET) {
        printf("Connection failed : %d", WSAGetLastError());
        return 1;
    }

    closesocket(s);
    WSACleanup();


    return 0;

}

当我运行这样时，服务器运行正常。我打开另一个终端并打开 telnet 并尝试连接到 8080 端口上的服务器。这是客户端。

Welcome to Microsoft Telnet Client

Escape Character is 'CTRL+]'

Microsoft Telnet> open localhost 8080
Connecting To localhost...

这是服务器端。

Listening for incoming connection

Connection established

但即使在服务器说连接已建立之后，客户端仍停留在 "Connecting to localhost"。我发送消息 "Thank you for connecting to us but i got to go\n" 但它没有显示在客户端。可能有什么问题？

Answer 1

看起来，这是一个愚蠢的错误。

while (new_socket = accept(s, (struct sockaddr*)&client, &c) != INVALID_SOCKET)

因为我没有在 new_socket = accept(s, (struct sockaddr*)&client, &c 初始化 new_socket 后加上另一个括号，不等式被应用到 accept函数return。

正确的语法是

while ((new_socket = accept(s, (struct sockaddr*)&client, &c)) != INVALID_SOCKET)

Winsock 服务器消息未显示在客户端终端上

Winsock server message isn't showing on client side terminal

tcp

winsock

winsock2

server