问raspbian上的getaddrinfo只返回回环IP，在OS倍数上返回相同的代码

EN

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <iostream>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <errno.h>
using namespace std;

int main (int argc, char * const argv[]) {
  char hostname[128];

  int result = gethostname(hostname, 127);
  if (result != 0)  {
    cout << "FATAL: gethostname failed: " << result << errno;
    return -1;
  }
  cout << "Host name is " << hostname << endl;

  struct addrinfo hints, *res;
  int errcode;
  char addrstr[100];
  void *ptr;

  memset(&hints, 0, sizeof(hints));
  hints.ai_family = PF_UNSPEC;
  hints.ai_socktype = SOCK_STREAM;
  hints.ai_flags |= AI_CANONNAME;

  errcode = getaddrinfo(hostname, NULL, &hints, &res);
  if (errcode != 0) {
    perror("getaddrinfo");
    return -1;
  }
  while(res) {
    inet_ntop(res->ai_family, res->ai_addr->sa_data, addrstr, 100);
    switch(res->ai_family) {
      case AF_INET:
        ptr = &((struct sockaddr_in *)res->ai_addr)->sin_addr;
        break;
      case AF_INET6:
        ptr = &((struct sockaddr_in6 *)res->ai_addr)->sin6_addr;
        break;
      default:
        cout << "Unknown family" << endl;
    }
    inet_ntop(res->ai_family, ptr, addrstr, 100);
    printf("IPV%d address: %s (%s)\n", res->ai_family == PF_INET6 ? 6 : 4, addrstr, res->ai_canonname);
    res = res->ai_next;
  }
  return 0;
}

[Coyote]collector$ ./quick
Host name is Coyote.local
IPV4 address: 192.168.1.108 (coyote.local)
IPV6 address: fe80::223:dfff:fea0:a230 (coyote.local)

pi:~$ ./quick
Host name is pi
IPV4 address: 127.0.1.1 (pi)

pi:~$ ifconfig
eth0      Link encap:Ethernet  HWaddr b8:27:eb:62:15:fc  
          inet addr:192.168.1.162  Bcast:192.168.1.255  Mask:255.255.255.0
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