应用：C/C++获取本机IP地址

/* 编译环境: visual c++ */
#include <stdio.h>
#include <winsock2.h>
#pragma comment(lib,"ws2_32.lib")
　　int doit(int, char **)
{
char host_name[255];
//获取本地主机名称
if (gethostname(host_name, sizeof(host_name)) == SOCKET_ERROR) {
printf("Error %d when getting local host name.n", WSAGetLastError());
return 1;
}
printf("Host name is: %sn", host_name);
　　//从主机名数据库中得到对应的“主机”
struct hostent *phe = gethostbyname(host_name);
if (phe == 0) {
printf("Yow! Bad host lookup.");
return 1;
}
　　//循环得出本地机器所有IP地址
for (int i = 0; phe->h_addr_list[i] != 0; ++i) {
struct in_addr addr;
memcpy(&addr, phe->h_addr_list[i], sizeof(struct in_addr));
printf("Address %d : %sn" , i, inet_ntoa(addr));
}
　　return 0;
}
　　int main(int argc, char *argv[])
{
WSAData wsaData;
if (WSAStartup(MAKEWORD(1, 1), &wsaData) != 0) {
return 255;
}
　　int retval = doit(argc, argv);
　　WSACleanup();
　　return retval;
}