学步园

使用gethostname() gethostbyname()等函数在Windows下去本机IP可以，但是到了Linux下就没用了：

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

	if ((fd = socket (AF_INET, SOCK_DGRAM, 0)) >= 0) //socket.h
	{ 
		ifc.ifc_len = sizeof buf; 
		ifc.ifc_buf = (caddr_t) buf; 
		if (!ioctl (fd, SIOCGIFCONF, (char *) &ifc)) //ioctl.h
		{ 
			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));//types 
					break;
				}           
			}
		} 
		close (fd); 
	}
	return ip;
}