Socket sk_register(void *sock, Plug plug)
Socket sk_register(OSSocket sockfd, Plug plug)
Socket sk_register(void *sock, Plug plug){    Actual_Socket ret;    /*     * Create Socket structure.     */    ret = snew(struct Socket_tag);    ret->fn = &tcp_fn_table;    ret->error = NULL;    ret->plug = plug;    bufchain_init(&ret->output_data);    ret->writable = 1;		       /* to start with */    ret->sending_oob = 0;    ret->frozen = 1;    ret->frozen_readable = 0;    ret->localhost_only = 0;	       /* unused, but best init anyway */    ret->pending_error = 0;    ret->oobpending = FALSE;    ret->listener = 0;    ret->s = (int)sock;    if (ret->s < 0) {	ret->error = error_string(errno);	return (Socket) ret;    }    ret->oobinline = 0;    uxsel_tell(ret);    add234(sktree, ret);    return (Socket) ret;}