上篇文章介绍了getaddrinfo替代gethostbyname 由域名获取IP的情况，本篇文章详细介绍getaddrinfo的用法。

其用法简单使用演示如下。windows下包含头文件#include ，Linux包含头文件#include。另外最重要的是hints参数的设置，详细参数说明可以参照百度百科，MSDN等等。

#include "stdafx.h"

#include 
#include 
#include 

#pragma comment (lib, "Ws2_32.lib")

int  main(int argc, char **argv)
{
	WORD wVersion;
	WSADATA WSAData;
	wVersion=MAKEWORD(2,2);
	WSAStartup(wVersion,&WSAData;);
	struct addrinfo hints;
    struct addrinfo *res, *cur;
	int ret;
    struct sockaddr_in *addr;
	char m_ipaddr[16];

    memset(&hints;, 0, sizeof(struct addrinfo));
    hints.ai_family = AF_INET; 	/* Allow IPv4 */
    hints.ai_flags = AI_PASSIVE;/* For wildcard IP address */
    hints.ai_protocol = 0; 		/* Any protocol */
    hints.ai_socktype = SOCK_STREAM;
       
    ret = getaddrinfo("www.cplusplus.me", NULL,&hints;,&res;);
    
    if (ret == -1) {
        perror("getaddrinfo");
        exit(1);
    }
	for (cur = res; cur != NULL; cur = cur->ai_next) {
        addr = (struct sockaddr_in *)cur->ai_addr;
        sprintf(m_ipaddr, "%d.%d.%d.%d",
		(*addr).sin_addr.S_un.S_un_b.s_b1,
		(*addr).sin_addr.S_un.S_un_b.s_b2,
		(*addr).sin_addr.S_un.S_un_b.s_b3,
		(*addr).sin_addr.S_un.S_un_b.s_b4);
		printf("%s\n",m_ipaddr);
    }
    freeaddrinfo(res);
	return 0;
}

百度IP获取如下所示，当然也可以获取www.cplusplus.me的IP地址信息。

getaddrinfo