iOS 根据域名查询 IP 地址

　　在 iOS 开发中，如果需要知道网站的 IP 地址：

#include <netdb.h>
#include <arpa/inet.h>

NSString *webSiteString = @"www.cnblogs.com";

//NSString to char*
const char *webSite = [webSiteString cStringUsingEncoding:NSASCIIStringEncoding];

// Get host entry info for given host
struct hostent *remoteHostEnt = gethostbyname(webSite);

// Get address info from host entry
struct in_addr *remoteInAddr = (struct in_addr *) remoteHostEnt->h_addr_list[];

// Convert numeric addr to ASCII string
char *sRemoteInAddr = inet_ntoa(*remoteInAddr);

//char* to NSString
NSString *ip = [[NSString alloc] initWithCString:sRemoteInAddr
                                            encoding:NSASCIIStringEncoding];
NSLog(@"ip:%@",ip);

　　打印结果：ip:101.37.225.65