TcpState *statePtr;
    SOCKET fd;
    struct TcpFdList *next;
} TcpFdList;

struct TcpState {
    Tcl_Channel channel;	/* Channel associated with this socket. */
    struct TcpFdList *sockets;	/* Windows SOCKET handle. */
    int flags;			/* Bit field comprised of the flags described
				 * below. */

    int watchEvents;		/* OR'ed combination of FD_READ, FD_WRITE,
				 * FD_CLOSE, FD_ACCEPT and FD_CONNECT that
				 * indicate which events are interesting. */
    volatile int readyEvents;	/* OR'ed combination of FD_READ, FD_WRITE,
				 * FD_CLOSE, FD_ACCEPT and FD_CONNECT that
				 * indicate which events have occurred.
				 * Set by notifier thread, access must be

    int cachedBlocking;         /* Cache blocking mode of async socket. */
    volatile int notifierConnectError;
				/* Async connect error set by notifier thread.
				 * This error is still a windows error code.
				 * Access must be protected by semaphore */
    struct TcpState *nextPtr;	/* The next socket on the per-thread socket
				 * list. */
    int testFlags;              /* bit field for tests. Is set by testsocket
                                 * test procedure */
};

/*
 * These bits may be ORed together into the "flags" field of a TcpState
 * structure.
 */

#define TCP_NONBLOCKING		(1<<0)	/* Socket with non-blocking I/O */
#define TCP_ASYNC_CONNECT	(1<<1)	/* Async connect in progress. */
#define SOCKET_EOF		(1<<2)	/* A zero read happened on the
					 * socket. */
#define SOCKET_PENDING		(1<<3)	/* A message has been sent for this
					 * socket */
#define TCP_ASYNC_PENDING	(1<<4)	/* TcpConnect was called to
					 * process an async connect. This
					 * flag indicates that reentry is
					 * still pending */
#define TCP_ASYNC_FAILED	(1<<5)	/* An async connect finally failed */

/*
 * These bits may be ORed together into the "testFlags" field of a TcpState
 * structure.
 */

#define TCP_ASYNC_TEST_MODE	(1<<0)	/* Async testing activated.  Do not
					 * automatically continue connection
					 * process */

/*
 * The following structure is what is added to the Tcl event queue when a
 * socket event occurs.
 */

     * In socket test mode do not continue with the connect
     * Exceptions are:
     * - Call by recv/send and blocking socket
     *   (errorCodePtr != NULL && !GOT_BITS(flags, TCP_NONBLOCKING))
     * - Call by the event queue (errorCodePtr == NULL)
     */

    if (GOT_BITS(statePtr->testFlags, TCP_ASYNC_TEST_MODE)
	    && errorCodePtr != NULL
            && GOT_BITS(statePtr->flags, TCP_NONBLOCKING)) {
	*errorCodePtr = EWOULDBLOCK;
	return -1;
    }

    /*

    /*
     * Go one step in async connect
     *
     * If any error is thrown save it as backround error to report eventually
     * below.
     */

    if (!GOT_BITS(statePtr->testFlags, TCP_ASYNC_TEST_MODE)) {
	WaitForConnect(statePtr, NULL);
    }

    sock = statePtr->sockets->fd;
    if (optionName != NULL) {
	len = strlen(optionName);
    }