iPhone获取3G DNS主机名和IP地址

Question

在 Objective C/C/C++ 中是否可以获取 3G/Cell 数据连接的当前 DNS 服务器 IP 地址？

环顾四周，找不到明确的答案。

Answer 1

#include <arpa/inet.h>
#include <ifaddrs.h>
#include <resolv.h>
#include <dns.h>

// 
- (NSString *) getDNSServers 
{
    NSMutableString *addresses = [[NSMutableString alloc]initWithString:@"DNS Addresses \n"];

    res_state res = malloc(sizeof(struct __res_state));

    int result = res_ninit(res);

    if ( result == 0 )
    {    
        for ( int i = 0; i < res->nscount; i++ )
        {
            NSString *s = [NSString stringWithUTF8String :  inet_ntoa(res->nsaddr_list[i].sin_addr)];
            [addresses appendFormat:@"%@\n",s];
            NSLog(@"%@",s);
        }
    }
    else 
        [addresses appendString:@" res_init result != 0"];

    return addresses;
    }