Linux下的C编程怎样获取本机的IP地址?

baconer

Linux下C语言编程,怎样才能获得本机的IP地址,用什么函数或宏?
该怎么编?哪位高手知道?盼尽快告知.

jsf99171

#include <netdb.h>

server_host_name=gethostbyname(host_name);
((struct in_addr *)(server_host_name->h_addr))->s_addr

baconer

((struct in_addr *)(server_host_name->h_addr))->s_addr这个就是IP地址吗

doubleelec

搜索论坛

nait

精华区看一下

libinyiyi

请问精华区在哪里：（

nait

Post by libinyiyi
请问精华区在哪里：（

晕，我看你也发了蛮多帖嘛 :confused:  :confused:  :confused:

baconer

还是不知道怎么编,哪位写一下完整的源代码?

haohao_h

仅仅适用IPv4,代码一定很幼稚，请大家指教啊！

1. #include <stdio.h>
   
2. #include <stdlib.h>
   
3. #include <sys/types.h>
   
4. #include <sys/socket.h>
   
5. #include <sys/ioctl.h>
   
6. #include <netinet/in.h>
   
7. #include <net/if.h>
   
8. #include <net/if_arp.h>
   
9. #include <arpa/inet.h>
   
10. #include <errno.h>
    
11. #include <unistd.h>
    
12. #include <net/route.h>
    
13. #include <string.h>
    
14. 
    
15. typedef struct
    
16. {
    
17.   char name[16];
    
18.   char address[16];
    
19.   char netmask[16];
    
20.   char broadcast[16];  
    
21.   char macaddr[18];
    
22. }if_info;
    
23. 
    
24. int read_if_info(if_info* info, size_t* len)
    
25. {
    
26.   int fd;
    
27.   int numreqs = 6;
    
28.   struct ifconf ifc;
    
29.   struct ifreq *ifr;
    
30.   int n;
    
31.   int idx = 0;
    
32.   int size;
    
33.   
    
34.   size = *len;
    
35. 
    
36.   fd = socket(AF_INET, SOCK_DGRAM, 0);
    
37. 
    
38.   memset(&ifc, 0, sizeof(struct ifconf));
    
39.   ifc.ifc_len = sizeof(struct ifreq) * numreqs;
    
40.   ifc.ifc_buf = (char*)malloc(ifc.ifc_len);
    
41. 
    
42.   do {
    
43.     if (ioctl(fd, SIOCGIFCONF, &ifc) < 0) {
    
44.       //perror("SIOCGIFCONF");
    
45.       goto err;
    
46.     }
    
47.     if (ifc.ifc_len == sizeof(struct ifreq) * numreqs) {
    
48.       /* assume it overflowed and try again */
    
49.       numreqs += 4;
    
50.       ifc.ifc_len = sizeof(struct ifreq) * numreqs;
    
51.       ifc.ifc_buf = (char*)realloc(ifc.ifc_buf, ifc.ifc_len);
    
52.       continue;
    
53.     }
    
54.     break;
    
55.   }while(1);
    
56. 
    
57.   ifr = ifc.ifc_req;
    
58. 
    
59.   for (n = 0; n < ifc.ifc_len; n += sizeof(struct ifreq)) {
    
60.     if (idx >= size){
    
61.       goto end;
    
62.     }       
    
63.    
    
64.     strcpy(info[idx].name, ifr->ifr_name);
    
65.     strcpy(info[idx].address,
    
66.            inet_ntoa(((struct sockaddr_in*)&ifr->ifr_addr)->sin_addr));
    
67.                
    
68.     if (ioctl(fd, SIOCGIFNETMASK, ifr) < 0)         {
    
69.       goto err;
    
70.     }
    
71. 
    
72.     strcpy(info[idx].netmask,
    
73.            inet_ntoa(((struct sockaddr_in*)&ifr->ifr_netmask)->sin_addr));
    
74.                
    
75.     if (ioctl(fd, SIOCGIFBRDADDR, ifr) < 0)         {
    
76.       goto err;
    
77.     }
    
78. 
    
79.     strcpy(info[idx].broadcast,
    
80.            inet_ntoa(((struct sockaddr_in*)&ifr->ifr_broadaddr)->sin_addr));
    
81.                
    
82.     if (ioctl(fd, SIOCGIFHWADDR, ifr) < 0)         {
    
83.       goto err;
    
84.     }                                
    
85.     sprintf(info[idx].macaddr, "%02X:%02X:%02X:%02X:%02X:%02X",(unsigned char)ifr->ifr_hwaddr.sa_data[0],\
    
86.             (unsigned char)ifr->ifr_hwaddr.sa_data[1],(unsigned char)ifr->ifr_hwaddr.sa_data[2],\
    
87.             (unsigned char)ifr->ifr_hwaddr.sa_data[3],(unsigned char)ifr->ifr_hwaddr.sa_data[4],\
    
88.             (unsigned char)ifr->ifr_hwaddr.sa_data[5]);       
    
89.     ifr++;
    
90.     idx++;
    
91.   }
    
92. 
    
93.   
    
94. 
    
95. end:
    
96.   free(ifc.ifc_buf);
    
97.   *len = idx;
    
98.   return 0;
    
99. 
    
100. err:
     
101.   free(ifc.ifc_buf);       
     
102.   
     
103.   return -1;       
     
104.   
     
105. }

复制代码

baconer

怎么这么麻烦,有没有简单一点的,代码太长了,大家帮忙看一下这段代码该怎么改:
    struct hostent *h;
    char *host_name;
    char *local_ip;

   if((gethostname(host_name,200))==-1){
           herror(" get host name");
           exit(1);
          }         
   if ((h=gethostbyname(host_name))==NULL) { /* get the host info */
       herror(" get host byname");
       exit(1);
       }
    printf("Host name : %s\n", h->h_name);     
    local_ip=(char*)((struct in_addr *)h->h_addr);
    printf("IP Address : %s\n",local_ip);
  编译能通过,但执行后得不到结果?