Linux is 本机ip question! ! ! Want 本机ip, code is posted before the forum, slightly changed a bit. My question is, A total of three joints, eth0, eth1, lo, are the up. However, procedures are shown DOWN. I netdevice a man, no problem, gdb a bit and found running ifr_flags struct ifreq does not seem to have a ifru_flags, but also for the translation of this is not the past. This is how it all about? As follows : (rh8.0) #include "Stdio.h>; #include "Sys/types.h>; #include "Sys/param.h>; #include "Sys/ioctl.h>; #include "Sys/socket.h>; #include "Net/if.h>; #include "Netinet/in.h>; #include "Net/if_arp.h>; Void get_ip () { Struct ifreq if_buf[16]; Struct ifconf ifc; Int fd, interface; If ((fd = socket (AF_INET, SOCK_DGRAM, 0)) "; 0)         { Ifc.ifc_len = sizeof (if_buf); Ifc.ifc_buf = (caddr_t) if_buf; If (!ioctl (fd, SIOCGIFCONF, (char *) &ifc))                 { Ifc.ifc_len/sizeof interface = (struct ifreq); Printf ( "%d interfaces\n" interface); While (interface-- "; 0)                           { Printf ( "net device %s\n" if_buf[interface].ifr_name); If (if_buf[interface].ifr_flags & IFF_UP) Puts ( "the interface status is UP"); Else Puts ( "the interface status is DOWN");                                 If (! (Ioctl (fd, SIOCGIFADDR, (char *) &if_buf[interface])))                                 { Puts ( "IP address is :"); Puts (inet_ntoa (((struct sockaddr_in*) (&if_buf[interface].ifr_addr)) ->;sin_addr)); Puts ( ""); //puts (Buf[interface].ifr_addr.sa_data);                                 }                         }                 }         } } Main () { Get_ip (); } Linux is 本机ip question! ! ! # IFF_UP 0x1 interface is up */ LEAVES OF 13 SPECIES OF LAURACEAE Struct ifreq { # 6 IFHWADDRLEN # 16 IFNAMSIZ Union         { Char ifrn_name[IFNAMSIZ]; LEAVES OF 13 SPECIES OF LAURACEAE if name, eg "en0" */ Ifr_ifrn;) Union ( Struct sockaddr ifru_addr; Struct sockaddr ifru_dstaddr; Struct sockaddr ifru_broadaddr; Struct sockaddr ifru_netmask; Struct sockaddr ifru_hwaddr; Short ifru_flags; Int ifru_ivalue; Int ifru_mtu; Struct ifmap ifru_map; Just fits the size */ char ifru_slave[IFNAMSIZ]; LEAVES OF 13 SPECIES OF LAURACEAE Char ifru_newname[IFNAMSIZ]; Char * ifru_data; Struct if_settings ifru_settings; Ifr_ifru;) }; # Ifr_flags ifr_ifru.ifru_flags LEAVES OF 13 SPECIES OF LAURACEAE flags */ Since the definition is ifru_flags Linux is 本机ip question! ! ! Thank you! ! ! I saw if.h that is the case. But the question is why the results are down? Ah, I ifconfig is up? Faint This is how it all about? [ Closed window ]