Linux下C语言获取本机IP地址

#include <sys/ioctl.h>
#include <net/if.h>
#include <arpa/inet.h>

char* GetLocalIp()
{
int MAXINTERFACES=16;
char *ip = NULL;
int fd, intrface, retn = 0;
struct ifreq buf[MAXINTERFACES];
struct ifconf ifc;

if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) >= 0)
{
ifc.ifc_len = sizeof(buf);
ifc.ifc_buf = (caddr_t)buf;
if (!ioctl(fd, SIOCGIFCONF, (char *)&ifc))
{
intrface = ifc.ifc_len / sizeof(struct ifreq);

while (intrface-- > 0)
{
if (!(ioctl (fd, SIOCGIFADDR, (char *) &buf[intrface])))
{
ip=(inet_ntoa(((struct sockaddr_in*)(&buf[intrface].ifr_addr))->sin_addr));
break;
}
}
}
close (fd);
return ip;
}
}