我目前正在尝试了解如何在Windows下使用头文件“winsock2.h”建立服务器-客户端连接。我已经从Microsoft（here）完成了“入门”，现在我有一个问题，我不能解决！
问题是我的程序在函数connect SOCKET_ERROR（WSAGetLastError == 11001 == WSAHOST_NOT_FOUND）（带有“www.google.com“）处返回。
所以我查了一下这里推荐的网站，然后也试了这个（www.contoso.com），结果是一样的。
如果有人能给我解释一下这个问题，我将非常感激！

constexpr auto DEFAULT_PORT   = "27015";
constexpr auto DEFAULT_BUFLEN = 512;
#pragma comment(lib, "Ws2_32.lib")
#include <winsock2.h>
#include <ws2tcpip.h>
#include <iostream>
...
WSADATA   wsa_data;
SOCKET    sock;
addrinfo* result = NULL;
addrinfo* ptr = NULL;
addrinfo  hints{};
PCSTR     port = DEFAULT_PORT;
WSAStartup(WINSOCK_VERSION, &wsa_data)
ZeroMemory(&hints, sizeof(hints));
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
// Resolve the server address and port
getaddrinfo(host_name, port, &hints, &result)
for (ptr = result; ptr != nullptr; ptr = ptr->ai_next) {
    sock = socket(ptr->ai_family, ptr->ai_socktype, ptr->ai_protocol);
    if (sock == INVALID_SOCKET) {
        std::cout << "\nERROR: socket failed: " << WSAGetLastError() << std::endl;
        freeaddrinfo(result);
        WSACleanUp();
        return WSAGetLastError();
    }
    if (connect(sock, ptr->ai_addr, (int)ptr->ai_addrlen) == SOCKET_ERROR) {
        closesocket(sock);
        sock = INVALID_SOCKET;
        continue;
    }
    break;
}
freeaddrinfo(result);
if (sock == INVALID_SOCKET) {
    std::cout << "\nERROR: unable to connect to server!\n";
    WSACleanUp();
    return WSAGetLastError();
}
WSACleanUp();

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编辑：忘记复制端口变量的初始化