*/

typedef struct TcpState TcpState;

typedef struct TcpFdList {
    TcpState *statePtr;
    int fd;
    int spareFd;
    struct TcpFdList *next;
} TcpFdList;

struct TcpState {
    Tcl_Channel channel;	/* Channel associated with this file. */
    TcpFdList fds;		/* The file descriptors of the sockets. */
    int flags;			/* ORed combination of the bitfields defined

     */

    for (fds = &statePtr->fds; fds != NULL; fds = fds->next) {
	if (fds->fd < 0) {
	    continue;
	}
	Tcl_DeleteFileHandler(fds->fd);
	if (fds->spareFd != -1) {
	    close(fds->spareFd);
	}
	if (close(fds->fd) < 0) {
	    errorCode = errno;
	}

    }
    fds = statePtr->fds.next;
    while (fds != NULL) {

        TclUnixSetBlockingMode(statePtr->fds.fd, statePtr->cachedBlocking);

        if (error != 0) {
            SET_BITS(statePtr->flags, TCP_ASYNC_FAILED);
        }

        /*
         * We need to forward the writable event that brought us here, because
         * upon reading of getsockopt(SO_ERROR), at least some OSes clear the
         * writable state from the socket, and so a subsequent select() on
         * behalf of a script level [fileevent] would not fire. It doesn't
         * hurt that this is also called in the successful case and will save
         * the event mechanism one roundtrip through select().
         */

    statePtr = ckalloc(sizeof(TcpState));
    memset(statePtr, 0, sizeof(TcpState));
    statePtr->flags = async ? TCP_ASYNC_CONNECT : 0;
    statePtr->cachedBlocking = TCL_MODE_BLOCKING;
    statePtr->addrlist = addrlist;
    statePtr->myaddrlist = myaddrlist;
    statePtr->fds.fd = -1;
    statePtr->fds.spareFd = -1;

    /*
     * Create a new client socket and wrap it in a channel.
     */

    if (TcpConnect(interp, statePtr) != TCL_OK) {
        TcpCloseProc(statePtr, NULL);

{
    TcpState *statePtr;
    char channelName[SOCK_CHAN_LENGTH];

    statePtr = ckalloc(sizeof(TcpState));
    memset(statePtr, 0, sizeof(TcpState));
    statePtr->fds.fd = PTR2INT(sock);
    statePtr->fds.spareFd = -1;
    statePtr->flags = 0;

    sprintf(channelName, SOCK_TEMPLATE, (long)statePtr);

    statePtr->channel = Tcl_CreateChannel(&tcpChannelType, channelName,
	    statePtr, mode);
    if (Tcl_SetChannelOption(NULL, statePtr->channel, "-translation",

            newfds = &statePtr->fds;
        } else {
            newfds = ckalloc(sizeof(TcpFdList));
            memset(newfds, (int) 0, sizeof(TcpFdList));
            fds->next = newfds;
        }
        newfds->fd = sock;
        newfds->spareFd = dup(sock);
        newfds->statePtr = statePtr;
        fds = newfds;

        /*
         * Set up the callback mechanism for accepting connections from new
         * clients.
         */

    socklen_t len;		/* For accept interface */
    char channelName[SOCK_CHAN_LENGTH];
    char host[NI_MAXHOST], port[NI_MAXSERV];

    len = sizeof(addr);
    newsock = accept(fds->fd, &addr.sa, &len);
    if (newsock < 0) {

	/*
	 * Last resort: try to cleanup the listen backlog. If that
	 * fails, a busy event loop is the most likely outcome.
	 * Due to process semantic of the file descriptor table
	 * this strategy is inherently not threadsafe. It could
	 * be remedied if there was a system call which combines
	 * accept() with dup() using a spare pre-allocated file
	 * descriptor. Otherwise, ALL system calls producing a
	 * new file descriptor would require to be mutexed in order
	 * to guarantee availability of that spare file descriptor.
	 */

	if (errno == EMFILE || errno == ENFILE) {
	    if (fds->spareFd != -1) {
		close(fds->spareFd);
		len = sizeof(addr);
		fds->spareFd = accept(fds->fd, &addr.sa, &len);
		if (fds->spareFd >= 0) {
		    close(fds->spareFd);
		    fds->spareFd = dup(fds->fd);
		}
	    }
	}
	return;
    }

    /*
     * Ticket [c6897e6e6a].
     */

    (void) fcntl(newsock, F_SETFD, FD_CLOEXEC);

    newSockState = ckalloc(sizeof(TcpState));
    memset(newSockState, 0, sizeof(TcpState));
    newSockState->flags = 0;
    newSockState->fds.fd = newsock;
    newSockState->fds.spareFd = -1;

    sprintf(channelName, SOCK_TEMPLATE, (long) newSockState);
    newSockState->channel = Tcl_CreateChannel(&tcpChannelType, channelName,
	    newSockState, TCL_READABLE | TCL_WRITABLE);

    Tcl_SetChannelOption(NULL, newSockState->channel, "-translation",
	    "auto crlf");