volatile int acceptEventCount;
				/* Count of the current number of FD_ACCEPTs
				 * that have arrived and not yet processed.
				 * Set by notifier thread, access must be
				 * protected by semaphore */
    Tcl_TcpAcceptProc *acceptProc;
				/* Proc to call on accept. */
    ClientData acceptProcData;	/* The data for the accept proc. */

    /*
     * Only needed for client sockets
     */

    struct addrinfo *addrlist;	/* Addresses to connect to. */
    struct addrinfo *addr;	/* Iterator over addrlist. */

 * Static routines for this file:
 */

static int		TcpConnect(Tcl_Interp *interp,
			    TcpState *state);
static void		InitSockets(void);
static TcpState *	NewSocketInfo(SOCKET socket);
static void		SocketExitHandler(ClientData clientData);
static LRESULT CALLBACK	SocketProc(HWND hwnd, UINT message, WPARAM wParam,
			    LPARAM lParam);
static int		SocketsEnabled(void);
static void		TcpAccept(TcpFdList *fds, SOCKET newSocket, address addr);
static int		WaitForConnect(TcpState *statePtr, int *errorCodePtr);
static int		WaitForSocketEvent(TcpState *statePtr, int events,
			    int *errorCodePtr);
static void		AddSocketInfoFd(TcpState *statePtr,  SOCKET socket);
static int		FindFDInList(TcpState *statePtr, SOCKET socket);
static DWORD WINAPI	SocketThread(LPVOID arg);
static void		TcpThreadActionProc(ClientData instanceData,
			    int action);
static int		TcpCloseProc(void *, Tcl_Interp *);

static Tcl_EventCheckProc	SocketCheckProc;
static Tcl_EventProc		SocketEventProc;
static Tcl_EventSetupProc	SocketSetupProc;
static Tcl_DriverBlockModeProc	TcpBlockModeProc;

 *	Sets the device into blocking or nonblocking mode.
 *
 *----------------------------------------------------------------------
 */

static int
TcpBlockModeProc(
    ClientData instanceData,	/* Socket state. */
    int mode)			/* The mode to set. Can be one of
				 * TCL_MODE_BLOCKING or
				 * TCL_MODE_NONBLOCKING. */
{
    TcpState *statePtr = (TcpState *)instanceData;

    if (mode == TCL_MODE_NONBLOCKING) {

 *	Reads input from the input device of the channel.
 *
 *----------------------------------------------------------------------
 */

static int
TcpInputProc(
    ClientData instanceData,	/* Socket state. */
    char *buf,			/* Where to store data read. */
    int bufSize,		/* How much space is available in the
				 * buffer? */
    int *errorCodePtr)		/* Where to store error code. */
{
    TcpState *statePtr = (TcpState *)instanceData;
    int bytesRead;

 *	Produces output on the socket.
 *
 *----------------------------------------------------------------------
 */

static int
TcpOutputProc(
    ClientData instanceData,	/* Socket state. */
    const char *buf,		/* The data buffer. */
    int toWrite,		/* How many bytes to write? */
    int *errorCodePtr)		/* Where to store error code. */
{
    TcpState *statePtr = (TcpState *)instanceData;
    int written;
    DWORD error;

 *	Closes the socket.
 *
 *----------------------------------------------------------------------
 */

static int
TcpCloseProc(
    ClientData instanceData,	/* The socket to close. */
    TCL_UNUSED(Tcl_Interp *))
{
    TcpState *statePtr = (TcpState *)instanceData;
    /* TIP #218 */
    int errorCode = 0;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

 *	Shuts down one side of the socket.
 *
 *----------------------------------------------------------------------
 */

static int
TcpClose2Proc(
    ClientData instanceData,	/* The socket to close. */
    Tcl_Interp *interp,		/* For error reporting. */
    int flags)			/* Flags that indicate which side to close. */
{
    TcpState *statePtr = (TcpState *)instanceData;
    int readError = 0;
    int writeError = 0;

 *	Changes attributes of the socket at the system level.
 *
 *----------------------------------------------------------------------
 */

static int
TcpSetOptionProc(
    ClientData instanceData,	/* Socket state. */
    Tcl_Interp *interp,		/* For error reporting - can be NULL. */
    const char *optionName,	/* Name of the option to set. */
    TCL_UNUSED(const char *) /*value*/)		/* New value for option. */
{
#ifdef TCL_FEATURE_KEEPALIVE_NAGLE
    TcpState *statePtr = instanceData;
    SOCKET sock;

 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
TcpGetOptionProc(
    ClientData instanceData,	/* Socket state. */
    Tcl_Interp *interp,		/* For error reporting - can be NULL. */
    const char *optionName,	/* Name of the option to retrieve the value
				 * for, or NULL to get all options and their
				 * values. */
    Tcl_DString *dsPtr)		/* Where to store the computed value;
				 * initialized by caller. */
{

 *	already true.
 *
 *----------------------------------------------------------------------
 */

static void
TcpWatchProc(
    ClientData instanceData,	/* The socket state. */
    int mask)			/* Events of interest; an OR-ed combination of
				 * TCL_READABLE, TCL_WRITABLE and
				 * TCL_EXCEPTION. */
{
    TcpState *statePtr = (TcpState *)instanceData;

    /*

 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
TcpGetHandleProc(
    ClientData instanceData,	/* The socket state. */
    TCL_UNUSED(int) /*direction*/,
    ClientData *handlePtr)	/* Where to store the handle. */
{
    TcpState *statePtr = (TcpState *)instanceData;

    *handlePtr = INT2PTR(statePtr->sockets->fd);
    return TCL_OK;
}

 *	None.
 *
 *----------------------------------------------------------------------
 */

Tcl_Channel
Tcl_MakeTcpClientChannel(
    ClientData sock)		/* The socket to wrap up into a channel. */
{
    TcpState *statePtr;
    char channelName[SOCK_CHAN_LENGTH];
    ThreadSpecificData *tsdPtr;

    if (TclpHasSockets(NULL) != TCL_OK) {
	return NULL;

    Tcl_Interp *interp,		/* For error reporting - may be NULL. */
    const char *service,	/* Port number to open. */
    const char *myHost,		/* Name of local host. */
    unsigned int flags,		/* Flags. */
    Tcl_TcpAcceptProc *acceptProc,
				/* Callback for accepting connections from new
				 * clients. */
    ClientData acceptProcData)	/* Data for the callback. */
{
    SOCKET sock = INVALID_SOCKET;
    unsigned short chosenport = 0;
    struct addrinfo *addrlist = NULL;
    struct addrinfo *addrPtr;	/* Socket address to listen on. */
    TcpState *statePtr = NULL;	/* The returned value. */
    char channelName[SOCK_CHAN_LENGTH];

 *	None.
 *
 *----------------------------------------------------------------------
 */

static void
SocketExitHandler(
    TCL_UNUSED(ClientData))
{
    Tcl_MutexLock(&socketMutex);

    /*
     * Make sure the socket event handling window is cleaned-up for, at
     * most, this thread.
     */

 *	Adjusts the block time if needed.
 *
 *----------------------------------------------------------------------
 */

void
SocketSetupProc(
    TCL_UNUSED(ClientData),
    int flags)			/* Event flags as passed to Tcl_DoOneEvent. */
{
    TcpState *statePtr;
    Tcl_Time blockTime = { 0, 0 };
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    if (!GOT_BITS(flags, TCL_FILE_EVENTS)) {

 *	May queue an event.
 *
 *----------------------------------------------------------------------
 */

static void
SocketCheckProc(
    TCL_UNUSED(ClientData),
    int flags)			/* Event flags as passed to Tcl_DoOneEvent. */
{
    TcpState *statePtr;
    SocketEvent *evPtr;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    if (!GOT_BITS(flags, TCL_FILE_EVENTS)) {

 *	Changes thread local list of valid channels.
 *
 *----------------------------------------------------------------------
 */

static void
TcpThreadActionProc(
    ClientData instanceData,
    int action)
{
    ThreadSpecificData *tsdPtr;
    TcpState *statePtr = (TcpState *)instanceData;
    int notifyCmd;

    if (action == TCL_CHANNEL_THREAD_INSERT) {