冒号的有关问题

struct pmem_bits {
    unsigned allocated:1;        /* 1 if allocated, 0 if free */
    unsigned order:7;        /* size of the region in pmem space */
};

struct proto_ops unix_dgram_ops = {
         family:         PF_UNIX,
         release:        unix_release,
         bind:           unix_bind,
         connect:        unix_dgram_connect,
         socketpair:     unix_socketpair,
         accept:         sock_no_accept,
         getname:        unix_getname,
         poll:           datagram_poll,
         ioctl:          unix_ioctl,
         listen:         sock_no_listen,
         shutdown:       unix_shutdown,
         setsockopt:     sock_no_setsockopt,
         getsockopt:     sock_no_getsockopt,
         sendmsg:        unix_dgram_sendmsg,
         recvmsg:        unix_dgram_recvmsg,
         mmap:           sock_no_mmap,
         sendpage:       sock_no_sendpage,
};