};

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

enum TcpStateFlags {
    TCP_NONBLOCKING = (1<<0),	/* Socket with non-blocking I/O */
    TCP_ASYNC_CONNECT = (1<<1),	/* Async connect in progress. */
    SOCKET_EOF = (1<<2),	/* A zero read happened on the socket. */

    SOCKET_PENDING = (1<<3),	/* A message has been sent for this socket */

    TCP_ASYNC_PENDING = (1<<4),	/* TcpConnect was called to process an async

                                 * connect. This flag indicates that reentry
                                 * is still pending. */
    TCP_ASYNC_FAILED = (1<<5)	/* An async connect finally failed */
};

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

enum TcpStateTestFlags {
    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.
 */

typedef struct {

static Tcl_ThreadDataKey dataKey;
static WNDCLASSW windowClass;

/*
 * 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);

 * Simple wrapper round the SendMessage syscall.
 */

#define SendSelectMessage(tsdPtr, message, payload)     \
    SendMessageW((tsdPtr)->hwnd, SOCKET_SELECT,          \
                (WPARAM) (message), (LPARAM) (payload))

/*
 * The name of a variable that may be changed to suppress reverse DNS lookups.
 */

#define SUPPRESS_RDNS_VAR "::tcl::unsupported::noReverseDNS"

/*
 * Address print debug functions
 */
#if 0
void
printaddrinfo(

    Tcl_Encoding *encodingPtr)
{
    WCHAR wbuf[256];
    DWORD length = sizeof(wbuf)/sizeof(WCHAR);
    Tcl_DString ds;

    Tcl_DStringInit(&ds);
    if (GetComputerNameExW(ComputerNamePhysicalDnsFullyQualified, wbuf,
            &length) != 0) {
	/*
	 * Convert string from native to UTF then change to lowercase.
	 */

	Tcl_UtfToLower(Tcl_WCharToUtfDString(wbuf, -1, &ds));

    } else {

    }

    /*
     * Single fd operation: Tcl_OpenTcpServer() does not set TCL_READABLE or
     * TCL_WRITABLE so this should never be called for a server socket.
     */

    if ((flags & TCL_CLOSE_READ) &&
            (shutdown(statePtr->sockets->fd, SD_RECEIVE) == SOCKET_ERROR)) {
	Tcl_WinConvertError((DWORD) WSAGetLastError());
	readError = Tcl_GetErrno();
    }
    if ((flags & TCL_CLOSE_WRITE) &&
            (shutdown(statePtr->sockets->fd, SD_SEND) == SOCKET_ERROR)) {
	Tcl_WinConvertError((DWORD) WSAGetLastError());
	writeError = Tcl_GetErrno();
    }
    return (readError != 0) ? readError : writeError;
}

/*

				 * initialized by caller. */
{
    TcpState *statePtr = (TcpState *)instanceData;
    char host[NI_MAXHOST], port[NI_MAXSERV];
    SOCKET sock;
    size_t len = 0;
    int reverseDNS = 0;


    /*
     * Check that WinSock is initialized; do not call it if not, to prevent
     * system crashes. This can happen at exit time if the exit handler for
     * WinSock ran before other exit handlers that want to use sockets.
     */

		/*
		 * Return error message.
		 */

		if (err) {
		    Tcl_WinConvertError(err);
		    Tcl_DStringAppend(dsPtr, Tcl_ErrnoMsg(Tcl_GetErrno()), -1);

		}
	    }
	}
	return TCL_OK;
    }

    if ((len > 1) && (optionName[1] == 'c') &&

    /*
     * Invoke the accept callback function.
     */

    if (statePtr->acceptProc != NULL) {
	getnameinfo(&(addr.sa), len, host, sizeof(host), port, sizeof(port),
                NI_NUMERICHOST | NI_NUMERICSERV);
	statePtr->acceptProc(statePtr->acceptProcData, newInfoPtr->channel,
		host, atoi(port));
    }
}

/*
 *----------------------------------------------------------------------
 *
 * InitSockets --

     * Populate new FD.
     */

    fds->fd = socket;
    fds->statePtr = statePtr;
    fds->next = NULL;
}


/*
 *----------------------------------------------------------------------
 *
 * NewSocketInfo --
 *
 *	This function allocates and initializes a new TcpState structure.
 *

 *	Processes socket events off the system queue.
 *
 *----------------------------------------------------------------------
 */

static int
WaitForSocketEvent(
    TcpState *statePtr,         /* Information about this socket. */
    int events,			/* Events to look for. May be one of
				 * FD_READ or FD_WRITE. */

    int *errorCodePtr)		/* Where to store errors? */
{
    int result = 1;
    int oldMode;
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *)TclThreadDataKeyGet(&dataKey);

    /*