有关获取主机的IPv4地址的问题？ [英] Question about getting IPv4 address of a host?

问题描述

Hello guys

我使用windows函数getaddrinfo来获取主机的IPv4地址。

  struct  addrinfo * aiList = NULL; 
  struct  addrinfo aiHints; 
  //  在此初始化aiHints  
 aiHints.ai_family = AF_INET; 
  int  iResult = getaddrinfo（szHostName，NULL，& aiHints，& aiList）; 
  const   struct  addrinfo * aiPtr = aiList; 
  while （aiPtr！= NULL）
 {
  const  < span class =code-keyword> struct  sockaddr * pSockAddr = aiPtr-> ai_addr; 
  //  此处打印pSockAddr代码的内容 
 aiPtr = aiPtr-> ai_next; 
} 

$ s $ b struct sockaddr的声明是：

  struct  sockaddr {
 ushort sa_family; 
  char  sa_data [ 14 ]; 
}; 

函数成功，本地主机的aiPtr-> ai_addr-> sa_data的值如下

{0,0,127,0 ，0,1,0,0,0,0,0,0,0,0,0,0}

为什么这里有两个前导零？

可能是ai_addr是struct sockaddr_in类型而且两个前导零是sockaddr_in的成员sin_port？

  struct  sockaddr_in {
  short  sin_family; 
  unsigned   short  sin_port; 
  struct  in_addr sin_addr; 
  char  sin_zero [ 8 ]; 
} 

我很困惑。任何机构都可以澄清发生了什么事吗？

提前致谢



编辑：原来的主题是：

关于get addrinfo返回的问题getaddrino

解决方案

当你使用 AF_INET ai_addr 成员指向 sockaddr_in 类型的对象。看看这里的示例 [< a href =http://msdn.microsoft.com/en-us/library/windows/desktop/ms737530(v=vs.85).aspx\"target =_ blanktitle =New Window> ^ ]。

Hello guys
I use windows function getaddrinfo to get the IPv4 address of a host.

struct addrinfo * aiList = NULL;
struct addrinfo aiHints;
//initialize aiHints here
aiHints.ai_family = AF_INET;
int iResult = getaddrinfo( szHostName, NULL, &aiHints, &aiList );
const struct addrinfo * aiPtr = aiList;
while ( aiPtr != NULL )
{
    const struct sockaddr * pSockAddr = aiPtr->ai_addr;
//  print contents of pSockAddr code here
    aiPtr = aiPtr->ai_next;
}

declaration for struct sockaddr is:

struct sockaddr {
 ushort sa_family;
 char sa_data[14];
};

The function succeed and the values of aiPtr->ai_addr->sa_data for localhost is as follows
{ 0, 0, 127, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
Why two leading zeros here?
May it be ai_addr is of type struct sockaddr_in and The two leading zeros is member sin_port of sockaddr_in?

struct sockaddr_in{
   short sin_family;
   unsigned short sin_port;
   struct in_addr sin_addr;
   char sin_zero[8];
}

I'm confused. can any body clarify whats happening?
Thanks in advance

Edit: the original subject was this:
Question about struct addrinfo returned by getaddrino

解决方案

When you use AF_INET the ai_addr member points to an object of type sockaddr_in. Take a look at the example here [^].

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