ioctl SIOCGIFINDEX 失败

occultist

       
        /* connect socket to NIC by name */
        strcpy(ifr.ifr_name, ifname);
        r = ioctl(*psock, SIOCGIFINDEX, &ifr);
        ifindex = ifr.ifr_ifindex;


调试看到r的值为-1
（ifindex 却也能获得内容）

        r = setsockopt(*psock, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout));
        r = setsockopt(*psock, SOL_SOCKET, SO_SNDTIMEO, &timeout, sizeof(timeout));
        i = 1;
        r = setsockopt(*psock, SOL_SOCKET, SO_DONTROUTE, &i, sizeof(i));
        /* connect socket to NIC by name */
        strcpy(ifr.ifr_name, ifname);
-》        r = ioctl(*psock, SIOCGIFINDEX, &ifr);
        ifindex = ifr.ifr_ifindex;
        strcpy(ifr.ifr_name, ifname);
        ifr.ifr_flags = 0;
        /* reset flags of NIC interface */
        r = ioctl(*psock, SIOCGIFFLAGS, &ifr);
        /* set flags of NIC interface, here promiscuous and broadcast */
        ifr.ifr_flags = ifr.ifr_flags || IFF_PROMISC || IFF_BROADCAST;
        r = ioctl(*psock, SIOCSIFFLAGS, &ifr);
        /* bind socket to protocol, in this case RAW EtherCAT */
        sll.sll_family = AF_PACKET;
        sll.sll_ifindex = ifindex;
        sll.sll_protocol = htons(ETH_P_ECAT);
        r = bind(*psock, (struct sockaddr *)&sll, sizeof(sll));

标号之前r值正确
之后一直错误

occultist

系统： Ubuntu 10.04
编译器：codeblocks
GCC编译出错
不会GCC单步