c - 获取地址信息 : A non-recoverable error occurred during a database lookup

Question

当运行以下 C 程序时，我从 Windows 10 上的 getaddrinfo() 收到这个奇怪的错误:

https://gist.github.com/anonymous/4406cb031791afba29e5

这是调用 getaddrinfo() 的代码的相关部分:

  int error;
  socket_t sock;
  struct sockaddr_in addr;
  struct addrinfo ai_hints, *ai_result, *ai_cur;
  #ifdef _WIN32
    int wsa_error;
    WSADATA wsa_data;
  #endif

  if (argc < 3) {
    fprintf(stderr, "Usage: %s <host> <port>\n", argv[0]);
    return 1;
  }

  #ifdef _WIN32
    wsa_error = WSAStartup(MAKEWORD(2, 2), &wsa_data);
    if (wsa_error != 0) {
      fprintf(stderr, "WSAStartup: %s\n",
          get_error_string(wsa_error, NULL, 0));
      return 2;
    }
  #endif

  puts("Hello, World!");

  sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
  if (sock == -1) {
    fprintf(stderr, "socket: %s\n",
        get_error_string(get_socket_error(), NULL, 0));
    return 3;
  }

  memset(&ai_hints, sizeof(ai_hints), 0);
  ai_hints.ai_family = AF_UNSPEC;
  ai_hints.ai_protocol = IPPROTO_TCP;
  ai_hints.ai_socktype = SOCK_STREAM;

  error = getaddrinfo(argv[1], argv[2], &ai_hints, &ai_result);
  if (error != 0) {
    fprintf(stderr, "getaddrinfo: %s\n", error);
    close(sock);
    return 4;
  }

每次程序运行时，无论我通过命令行传递什么主机名和端口，它都会输出以下内容:

Hello, World!
getaddrinfo: A non-recoverable error occurred during a database lookup.

我也写了一个相应的服务器程序，它工作得很好(用telnet检查过!)。

你能看出我的代码有什么问题吗？

编辑:

它在 Linux 上似乎工作正常，getaddrinfo() 没有给出任何错误，客户端能够连接到我的服务器。

Answer 1

万岁!我找到了!

事实证明，我在初始化 ai_hints 时弄乱了 memset() 中的参数顺序，即:

  memset(&ai_hints, sizeof(ai_hints), 0);

应该是:

  memset(&ai_hints, 0, sizeof(ai_hints));

太糟糕了，我没有完整阅读getaddrinfo()文档，它准确描述了这个错误情况:

pHints [in, optional]

A pointer to an addrinfo structure that provides hints about the type of socket the caller supports.

The ai_addrlen, ai_canonname, ai_addr, and ai_next members of the addrinfo structure pointed to by the pHints parameter must be zero or NULL. Otherwise the GetAddrInfoEx function will fail with WSANO_RECOVERY.