TIP#219 IMPLEMENTATION

	* doc/SetChanErr.3: ** New File **. Documentation of the new
	  channel API functions.
	* generic/tcl.decls:  Stub declarations of the new channel API.
	* generic/tclDecls.h: Regenerated
	* generic/tclStubInit.c:

	* tclIORChan.c: ** New File **. Implementation of the reflected
	  channel.
	* generic/tclInt.h: Integration of reflected channel and new error
	* generic/tclIO.c:  propagation into the generic I/O core.
	* generic/tclIOCmd.c:
	* generic/tclIO.h:
	* library/init.tcl:

	* tests/io.test:    Extended testsuite.
	* tests/ioCmd.test:
	* tests/chan.test:
	* generic/tclTest.c:
	* generic/tclThreadTest.c:

	* unix/Makefile.in: Integration into the build machinery.
	* win/Makefile.in:
	* win/Makefile.vc:

1 files changed, 2668 insertions, 0 deletions

diff --git a/generic/tclIORChan.c b/generic/tclIORChan.c
new file mode 100644
index 0000000..beebff4
--- /dev/null
+++ b/generic/tclIORChan.c
@@ -0,0 +1,2668 @@
+/* 
+ * tclIORChan.c --
+ *
+ *	This file contains the implementation of Tcl's generic
+ *	channel reflection code, which allows the implementation
+ *	of Tcl channels in Tcl code.
+ *
+ *	Parts of this file are based on code contributed by 
+ *	Jean-Claude Wippler.
+ *
+ *      See TIP #219 for the specification of this functionality.
+ *
+ * Copyright (c) 2004-2005 ActiveState, a divison of Sophos
+ *
+ * See the file "license.terms" for information on usage and redistribution
+ * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+ *
+ * RCS: @(#) $Id: tclIORChan.c,v 1.1 2005/08/24 17:56:23 andreas_kupries Exp $
+ */
+
+#include <tclInt.h>
+#include <tclIO.h>
+#include <assert.h>
+
+#ifndef EINVAL
+#define EINVAL 9
+#endif
+#ifndef EOK
+#define EOK    0
+#endif
+
+/*
+ * Signatures of all functions used in the C layer of the reflection.
+ */
+
+/* Required */
+static int	RcClose _ANSI_ARGS_((ClientData clientData,
+		   Tcl_Interp *interp));
+
+/* Required, "read" is optional despite this. */
+static int	RcInput _ANSI_ARGS_((ClientData clientData,
+		    char *buf, int toRead, int *errorCodePtr));
+
+/* Required, "write" is optional despite this. */
+static int	RcOutput _ANSI_ARGS_((ClientData clientData,
+	            CONST char *buf, int toWrite, int *errorCodePtr));
+
+/* Required */
+static void	RcWatch _ANSI_ARGS_((ClientData clientData, int mask));
+
+/* NULL'able - "blocking", is optional */
+static int	RcBlock _ANSI_ARGS_((ClientData clientData,
+				       int mode));
+
+/* NULL'able - "seek", is optional */
+static Tcl_WideInt RcSeekWide _ANSI_ARGS_((ClientData clientData,
+		    Tcl_WideInt offset,
+		    int mode, int *errorCodePtr));
+
+static int RcSeek _ANSI_ARGS_((ClientData clientData,
+		    long offset, int mode, int *errorCodePtr));
+
+/* NULL'able - "cget" / "cgetall", are optional */
+static int	RcGetOption _ANSI_ARGS_((ClientData clientData,
+				       Tcl_Interp* interp,
+				       CONST char *optionName,
+				       Tcl_DString *dsPtr));
+
+/* NULL'able - "configure", is optional */
+static int	RcSetOption _ANSI_ARGS_((ClientData clientData,
+				       Tcl_Interp* interp,
+				       CONST char *optionName,
+				       CONST char *newValue));
+
+
+/*
+ * The C layer channel type/driver definition used by the reflection.
+ * This is a version 3 structure.
+ */
+
+static Tcl_ChannelType tclRChannelType = {
+  "tclrchannel",  /* Type name.                                    */
+  TCL_CHANNEL_VERSION_3,
+  RcClose,        /* Close channel, clean instance data            */
+  RcInput,        /* Handle read request                           */
+  RcOutput,       /* Handle write request                          */
+  RcSeek,         /* Move location of access point.    NULL'able   */
+  RcSetOption,    /* Set options.                      NULL'able   */
+  RcGetOption,    /* Get options.                      NULL'able   */
+  RcWatch,        /* Initialize notifier                           */
+  NULL,           /* Get OS handle from the channel.   NULL'able   */
+  NULL,           /* No close2 support.                NULL'able   */
+  RcBlock,        /* Set blocking/nonblocking.         NULL'able   */
+  NULL,           /* Flush channel. Not used by core.  NULL'able   */
+  NULL,           /* Handle events.                    NULL'able   */
+  RcSeekWide      /* Move access point (64 bit).       NULL'able   */
+};
+
+/*
+ * Instance data for a reflected channel. ===========================
+ */
+
+typedef struct {
+  Tcl_Channel chan;    /* Back reference to generic channel structure.
+		        */
+  Tcl_Interp* interp;  /* Reference to the interpreter containing the
+		        * Tcl level part of the channel. */
+#ifdef TCL_THREADS
+  Tcl_ThreadId thread; /* Thread the 'interp' belongs to. */
+#endif
+
+  /* See [==] as well.
+   * Storage for the command prefix and the additional words required
+   * for the invocation of methods in the command handler.
+   *
+   * argv [0] ... [.] | [argc-2] [argc-1] | [argc]  [argc+2]
+   *      cmd ... pfx | method   chan     | detail1 detail2
+   *      ~~~~ CT ~~~            ~~ CT ~~
+   *
+   * CT = Belongs to the 'Command handler Thread'.
+   */
+
+  int       argc;       /* Number of preallocated words - 2 */
+  Tcl_Obj** argv;       /* Preallocated array for calling the handler.
+			 * args [0] is placeholder for cmd word.
+			 * Followed by the arguments in the prefix,
+			 * plus 4 placeholders for method, channel,
+			 * and at most two varying (method specific)
+			 * words.
+			 */
+
+  int methods;          /* Bitmask of supported methods */
+
+  /* ---------------------------------------- */
+
+  /* NOTE (9): Should we have predefined shared literals
+   * NOTE (9): for the method names ?
+   */
+
+  /* ---------------------------------------- */
+
+  int mode;             /* Mask of R/W mode */
+  int interest;         /* Mask of events the channel is interested in. */
+
+  /* Note regarding the usage of timers.
+   *
+   * Most channel implementations need a timer in the
+   * C level to ensure that data in buffers is flushed
+   * out through the generation of fake file events.
+   *
+   * See 'rechan', 'memchan', etc.
+   *
+   * Here this is _not_ required. Interest in events is
+   * posted to the Tcl level via 'watch'. And posting of
+   * events is possible from the Tcl level as well, via
+   * 'chan postevent'. This means that the generation of
+   * all events, fake or not, timer based or not, is
+   * completely in the hands of the Tcl level. Therefore
+   * no timer here.
+   */
+
+} ReflectingChannel;
+
+/*
+ * Event literals. ==================================================
+ */
+
+static CONST char *eventOptions[] = {
+  "read", "write", (char *) NULL
+};
+typedef enum {
+  EVENT_READ, EVENT_WRITE
+} EventOption;
+
+/*
+ * Method literals. ==================================================
+ */
+
+static CONST char *methodNames[] = {
+  "blocking",	/* OPT */
+  "cget",	/* OPT \/ Together or none */
+  "cgetall",	/* OPT /\ of these two     */
+  "configure",	/* OPT */
+  "finalize",	/*     */
+  "initialize",	/*     */
+  "read",	/* OPT */
+  "seek",	/* OPT */
+  "watch",	/*     */
+  "write",	/* OPT */
+  (char *) NULL
+};
+typedef enum {
+  METH_BLOCKING,
+  METH_CGET,
+  METH_CGETALL,
+  METH_CONFIGURE,
+  METH_FINAL,
+  METH_INIT,
+  METH_READ,
+  METH_SEEK,
+  METH_WATCH,
+  METH_WRITE,
+} MethodName;
+
+#define FLAG(m) (1 << (m))
+#define REQUIRED_METHODS (FLAG (METH_INIT) | FLAG (METH_FINAL) | FLAG (METH_WATCH))
+#define NULLABLE_METHODS (FLAG (METH_BLOCKING) | FLAG (METH_SEEK) | \
+	FLAG (METH_CONFIGURE) | FLAG (METH_CGET) | FLAG (METH_CGETALL))
+
+#define RANDW (TCL_READABLE|TCL_WRITABLE)
+
+#define IMPLIES(a,b) ((!(a)) || (b))
+#define NEGIMPL(a,b)
+#define HAS(x,f) (x & FLAG(f))
+
+
+#ifdef TCL_THREADS
+/*
+ * Thread specific types and structures.
+ *
+ * We are here essentially creating a very specific implementation of
+ * 'thread send'.
+ */
+
+/*
+ * Enumeration of all operations which can be forwarded.
+ */
+
+typedef enum {
+  RcOpClose,
+  RcOpInput,
+  RcOpOutput,
+  RcOpSeek,
+  RcOpWatch,
+  RcOpBlock,
+  RcOpSetOpt,
+  RcOpGetOpt,
+  RcOpGetOptAll
+} RcOperation;
+
+/*
+ * Event used to forward driver invocations to the thread actually
+ * managing the channel. We cannot construct the command to execute
+ * and forward that. Because then it will contain a mixture of
+ * Tcl_Obj's belonging to both the command handler thread (CT), and
+ * the thread managing the channel (MT), executed in CT. Tcl_Obj's are
+ * not allowed to cross thread boundaries. So we forward an operation
+ * code, the argument details ,and reference to results. The command
+ * is assembled in the CT and belongs fully to that thread. No sharing
+ * problems.
+ */
+
+typedef struct RcForwardParamBase {
+  int   code; /* O: Ok/Fail of the cmd handler */
+  char* msg;  /* O: Error message for handler failure */
+  int   vol;  /* O: True - msg is allocated, False - msg is static */
+} RcForwardParamBase;
+
+/*
+ * Operation specific parameter/result structures.
+ */
+
+typedef struct RcForwardParamClose {
+  RcForwardParamBase b;
+} RcForwardParamClose;
+
+typedef struct RcForwardParamInput {
+  RcForwardParamBase b;
+  char* buf;    /* O: Where to store the read bytes */
+  int   toRead; /* I: #bytes to read,
+		 * O: #bytes actually read */
+} RcForwardParamInput;
+
+typedef struct RcForwardParamOutput {
+  RcForwardParamBase b;
+  CONST char* buf;     /* I: Where the bytes to write come from */
+  int         toWrite; /* I: #bytes to write,
+			* O: #bytes actually written */
+} RcForwardParamOutput;
+
+typedef struct RcForwardParamSeek {
+  RcForwardParamBase b;
+  int         seekMode; /* I: How to seek */
+  Tcl_WideInt offset;   /* I: Where to seek,
+			 * O: New location */
+} RcForwardParamSeek;
+
+typedef struct RcForwardParamWatch {
+  RcForwardParamBase b;
+  int mask; /* I: What events to watch for */
+} RcForwardParamWatch;
+
+typedef struct RcForwardParamBlock {
+  RcForwardParamBase b;
+  int nonblocking; /* I: What mode to activate */
+} RcForwardParamBlock;
+
+typedef struct RcForwardParamSetOpt {
+  RcForwardParamBase b;
+  CONST char* name;  /* Name of option to set */
+  CONST char* value; /* Value to set */
+} RcForwardParamSetOpt;
+
+typedef struct RcForwardParamGetOpt {
+  RcForwardParamBase b;
+  CONST char*  name;  /* Name of option to get, maybe NULL */
+  Tcl_DString* value; /* Result */
+} RcForwardParamGetOpt;
+
+/*
+ * General event structure, with reference to
+ * operation specific data.
+ */
+
+typedef struct RcForwardingEvent {
+  Tcl_Event                  event; /* Basic event data, has to be first item */
+  struct RcForwardingResult* resultPtr;
+
+  RcOperation               op;    /* Forwarded driver operation */
+  ReflectingChannel*        rcPtr; /* Channel instance */
+  CONST RcForwardParamBase* param; /* Arguments, a RcForwardParamXXX pointer */
+} RcForwardingEvent;
+
+/*
+ * Structure to manage the result of the forwarding.  This is not the
+ * result of the operation itself, but about the success of the
+ * forward event itself. The event can be successful, even if the
+ * operation which was forwarded failed. It is also there to manage
+ * the synchronization between the involved threads.
+ */
+
+typedef struct RcForwardingResult {
+
+  Tcl_ThreadId  src;    /* Originating thread. */
+  Tcl_ThreadId  dst;    /* Thread the op was forwarded to. */
+  Tcl_Condition done;   /* Condition variable the forwarder blocks on. */
+  int           result; /* TCL_OK or TCL_ERROR */
+
+  struct RcForwardingEvent*  evPtr; /* Event the result belongs to. */
+
+  struct RcForwardingResult* prevPtr; /* Links into the list of pending */
+  struct RcForwardingResult* nextPtr; /* forwarded results. */
+
+} RcForwardingResult;
+
+/*
+ * List of forwarded operations which have not completed yet, plus the
+ * mutex to protect the access to this process global list.
+ */
+
+static RcForwardingResult* forwardList = (RcForwardingResult*) NULL;
+TCL_DECLARE_MUTEX (rcForwardMutex)
+
+/*
+ * Function containing the generic code executing a forward, and
+ * wrapper macros for the actual operations we wish to forward.
+ */
+
+static void
+RcForwardOp _ANSI_ARGS_ ((ReflectingChannel* rcPtr, RcOperation op,
+			  Tcl_ThreadId dst, CONST VOID* param));
+
+/*
+ * The event function executed by the thread receiving a forwarding
+ * event. Executes the appropriate function and collects the result,
+ * if any.
+ */
+
+static int
+RcForwardProc _ANSI_ARGS_ ((Tcl_Event *evPtr, int mask));
+
+/*
+ * Helpers which intercept when threads are going away, and clean up
+ * after pending forwarding events. Different actions depending on
+ * which thread went away, originator (src), or receiver (dst).
+ */
+
+static void
+RcSrcExitProc _ANSI_ARGS_ ((ClientData clientData));
+
+static void
+RcDstExitProc _ANSI_ARGS_ ((ClientData clientData));
+
+#define RcFreeReceivedError(pb) \
+	if ((pb).vol) {ckfree ((pb).msg);}
+
+#define RcPassReceivedErrorInterp(i,pb) \
+	if ((i)) {Tcl_SetChannelErrorInterp ((i), Tcl_NewStringObj ((pb).msg,-1));} \
+	RcFreeReceivedError (pb)
+
+#define RcPassReceivedError(c,pb) \
+	Tcl_SetChannelError ((c), Tcl_NewStringObj ((pb).msg,-1)); \
+	RcFreeReceivedError (pb)
+
+#define RcForwardSetStaticError(p,emsg) \
+       (p)->code = TCL_ERROR; (p)->vol  = 0; (p)->msg  = (char*) (emsg);
+
+#define RcForwardSetDynError(p,emsg) \
+       (p)->code = TCL_ERROR; (p)->vol  = 1; (p)->msg  = (char*) (emsg);
+
+static void
+RcForwardSetObjError _ANSI_ARGS_ ((RcForwardParamBase* p,
+				   Tcl_Obj*            obj));
+
+#endif /* TCL_THREADS */
+
+#define RcSetChannelErrorStr(c,msg) \
+	Tcl_SetChannelError ((c), Tcl_NewStringObj ((msg),-1))
+
+static Tcl_Obj* RcErrorMarshall _ANSI_ARGS_ ((Tcl_Interp *interp));
+static void     RcErrorReturn   _ANSI_ARGS_ ((Tcl_Interp* interp, Tcl_Obj* msg));
+
+
+
+/*
+ * Static functions for this file:
+ */
+
+static int RcEncodeEventMask _ANSI_ARGS_((Tcl_Interp* interp,
+		 CONST char* objName, Tcl_Obj* obj,
+		 int* mask));
+
+static Tcl_Obj* RcDecodeEventMask _ANSI_ARGS_ ((int mask));
+
+static ReflectingChannel* RcNew _ANSI_ARGS_ ((Tcl_Interp* interp,
+	     Tcl_Obj* cmdpfxObj, int mode,
+	     Tcl_Obj* id));
+
+static Tcl_Obj* RcNewHandle _ANSI_ARGS_ ((void));
+
+static void RcFree _ANSI_ARGS_ ((ReflectingChannel* rcPtr));
+
+static void
+RcInvokeTclMethod _ANSI_ARGS_((ReflectingChannel* rcPtr,
+       CONST char* method, Tcl_Obj* argone, Tcl_Obj* argtwo,
+       int* result, Tcl_Obj** resultObj, int capture));
+
+#define NO_CAPTURE (0)
+#define DO_CAPTURE (1)
+
+/*
+ * Global constant strings (messages). ==================
+ * These string are used directly as bypass errors, thus they have to be valid
+ * Tcl lists where the last element is the message itself. Hence the
+ * list-quoting to keep the words of the message together. See also [x].
+ */
+
+static CONST char* msg_read_unsup       = "{read not supported by Tcl driver}";
+static CONST char* msg_read_toomuch     = "{read delivered more than requested}";
+static CONST char* msg_write_unsup      = "{write not supported by Tcl driver}";
+static CONST char* msg_write_toomuch    = "{write wrote more than requested}";
+static CONST char* msg_seek_beforestart = "{Tried to seek before origin}";
+
+#ifdef TCL_THREADS
+static CONST char* msg_send_originlost  = "{Origin thread lost}";
+static CONST char* msg_send_dstlost     = "{Destination thread lost}";
+#endif /* TCL_THREADS */
+
+/*
+ * Main methods to plug into the 'chan' ensemble'. ==================
+ */
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclChanCreateObjCmd --
+ *
+ *	This procedure is invoked to process the "chan create" Tcl
+ *	command. See the user documentation for details on what it does.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *	The handle of the new channel is placed in the interp result.
+ *
+ * Side effects:
+ *	Creates a new channel.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclChanCreateObjCmd (/*ignored*/ clientData, interp, objc, objv)
+     ClientData      clientData;
+     Tcl_Interp*     interp;
+     int             objc;
+     Tcl_Obj* CONST* objv;
+{
+    ReflectingChannel* rcPtr;       /* Instance data of the new channel */
+    Tcl_Obj*           rcId;        /* Handle of the new channel */
+    int                mode;        /* R/W mode of new channel. Has to
+				     * match abilities of handler commands */
+    Tcl_Obj*           cmdObj;      /* Command prefix, list of words */
+    Tcl_Obj*           cmdNameObj;  /* Command name */
+    Tcl_Channel        chan;        /* Token for the new channel */
+    Tcl_Obj*           modeObj;     /* mode in obj form for method call */
+    int                listc;       /* Result of 'initialize', and of */
+    Tcl_Obj**          listv;       /* its sublist in the 2nd element */
+    int                methIndex;   /* Encoded method name */
+    int                res;         /* Result code for 'initialize' */
+    Tcl_Obj*           resObj;      /* Result data for 'initialize' */
+    int                methods;     /* Bitmask for supported methods. */
+    Channel*           chanPtr;     /* 'chan' resolved to internal struct. */
+
+    /* Syntax:   chan create MODE CMDPREFIX
+     *           [0]  [1]    [2]  [3]
+     *
+     * Actually: rCreate MODE CMDPREFIX
+     *           [0]     [1]  [2]
+     */
+
+#define MODE (1)
+#define CMD  (2)
+
+    /* Number of arguments ... */
+
+    if (objc != 3) {
+        Tcl_WrongNumArgs(interp, 1, objv, "mode cmdprefix");
+	return TCL_ERROR;
+    }
+
+    /* First argument is a list of modes. Allowed entries are "read",
+     * "write". Expect at least one list element.  Abbreviations are
+     * ok.
+     */
+
+    modeObj = objv [MODE];
+    if (RcEncodeEventMask (interp, "mode", objv [MODE], &mode) != TCL_OK) {
+        return TCL_ERROR;
+    }
+
+    /* Second argument is command prefix, i.e. list of words, first
+     * word is name of handler command, other words are fixed
+     * arguments. Run 'initialize' method to get the list of supported
+     * methods. Validate this.
+     */
+
+    cmdObj = objv [CMD];
+
+    /* Basic check that the command prefix truly is a list. */
+
+    if (Tcl_ListObjIndex(interp, cmdObj, 0, &cmdNameObj) != TCL_OK) {
+        return TCL_ERROR;
+    }
+
+    /* Now create the channel.
+     */
+
+    rcId  = RcNewHandle ();
+    rcPtr = RcNew (interp, cmdObj, mode, rcId);
+    chan  = Tcl_CreateChannel (&tclRChannelType,
+			       Tcl_GetString (rcId),
+			       rcPtr, mode);
+    rcPtr->chan = chan;
+    chanPtr = (Channel*) chan;
+
+    /* Invoke 'initialize' and validate that the handler
+     * is present and ok. Squash the channel if not.
+     */
+
+    /* Note: The conversion of 'mode' back into a Tcl_Obj ensures that
+     * 'initialize' is invoked with canonical mode names, and no
+     * abbreviations. Using modeObj directly could feed abbreviations
+     * into the handler, and the handler is not specified to handle
+     * such.
+     */
+
+    modeObj = RcDecodeEventMask (mode);
+    RcInvokeTclMethod (rcPtr, "initialize", modeObj, NULL,
+		       &res, &resObj, NO_CAPTURE);
+    Tcl_DecrRefCount (modeObj);
+
+    if (res != TCL_OK) {
+        Tcl_Obj* err = Tcl_NewStringObj ("Initialize failure: ",-1);
+
+	Tcl_AppendObjToObj(err,resObj);
+	Tcl_SetObjResult (interp,err);
+	Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+	goto error;
+    }
+
+    /* Verify the result.
+     * - List, of method names. Convert to mask.
+     *   Check for non-optionals through the mask.
+     *   Compare open mode against optional r/w.
+     */
+
+    Tcl_AppendResult (interp, "Initialize failure: ", (char*) NULL);
+
+    if (Tcl_ListObjGetElements (interp, resObj,
+			&listc, &listv) != TCL_OK) {
+        /* The function above replaces my prefix in case of an error,
+	 * so more work for us to get the prefix back into the error
+	 * message
+	 */
+
+        Tcl_Obj* err = Tcl_NewStringObj ("Initialize failure: ",-1);
+
+	Tcl_AppendObjToObj(err,Tcl_GetObjResult (interp));
+	Tcl_SetObjResult (interp,err);
+	goto error;
+    }
+
+    methods = 0;
+    while (listc > 0) {
+        if (Tcl_GetIndexFromObj (interp, listv [listc-1],
+				 methodNames, "method", TCL_EXACT, &methIndex) != TCL_OK) {
+	    Tcl_Obj* err = Tcl_NewStringObj ("Initialize failure: ",-1);
+
+	    Tcl_AppendObjToObj(err,Tcl_GetObjResult (interp));
+	    Tcl_SetObjResult (interp,err);
+	    goto error;
+	}
+
+	methods |= FLAG (methIndex);
+	listc --;
+    }
+
+    if ((REQUIRED_METHODS & methods) != REQUIRED_METHODS) {
+        Tcl_AppendResult (interp, "Not all required methods supported",
+			  (char*) NULL);
+	goto error;
+    }
+
+    if ((mode & TCL_READABLE) && !HAS(methods,METH_READ)) {
+        Tcl_AppendResult (interp, "Reading not supported, but requested",
+			  (char*) NULL);
+	goto error;
+    }
+
+    if ((mode & TCL_WRITABLE) && !HAS(methods,METH_WRITE)) {
+        Tcl_AppendResult (interp, "Writing not supported, but requested",
+			  (char*) NULL);
+	goto error;
+    }
+
+    if (!IMPLIES (HAS(methods,METH_CGET), HAS(methods,METH_CGETALL))) {
+        Tcl_AppendResult (interp, "'cgetall' not supported, but should be, as 'cget' is",
+			  (char*) NULL);
+	goto error;
+    }
+
+    if (!IMPLIES (HAS(methods,METH_CGETALL),HAS(methods,METH_CGET))) {
+        Tcl_AppendResult (interp, "'cget' not supported, but should be, as 'cgetall' is",
+			  (char*) NULL);
+	goto error;
+    }
+
+    Tcl_ResetResult (interp);
+
+    /* Everything is fine now */
+
+    rcPtr->methods = methods;
+
+    if ((methods & NULLABLE_METHODS) != NULLABLE_METHODS) {
+        /* Some of the nullable methods are not supported.  We clone
+	 * the channel type, null the associated C functions, and use
+	 * the result as the actual channel type.
+	 */
+
+        Tcl_ChannelType* clonePtr = (Tcl_ChannelType*) ckalloc (sizeof (Tcl_ChannelType));
+	if (clonePtr == (Tcl_ChannelType*) NULL) {
+	    Tcl_Panic ("Out of memory in Tcl_RcCreate");
+	}
+
+	memcpy (clonePtr, &tclRChannelType, sizeof (Tcl_ChannelType));
+
+	if (!(methods & FLAG (METH_CONFIGURE))) {
+	  clonePtr->setOptionProc = NULL;
+	}
+
+	if (
+	    !(methods & FLAG (METH_CGET)) &&
+	    !(methods & FLAG (METH_CGETALL))
+	    ) {
+	    clonePtr->getOptionProc = NULL;
+	}
+	if (!(methods & FLAG (METH_BLOCKING))) {
+	    clonePtr->blockModeProc = NULL;
+	}
+	if (!(methods & FLAG (METH_SEEK))) {
+	    clonePtr->seekProc     = NULL;
+	    clonePtr->wideSeekProc = NULL;
+	}
+
+	chanPtr->typePtr = clonePtr;
+    }
+
+    Tcl_RegisterChannel (interp, chan);
+
+    /* Return handle as result of command */
+
+    Tcl_SetObjResult (interp, rcId);
+    return TCL_OK;
+
+ error:
+    /* Signal to RcClose to not call 'finalize' */
+    rcPtr->methods = 0;
+    Tcl_Close (interp, chan);
+    return TCL_ERROR;
+
+#undef MODE
+#undef CMD
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclChanPostEventObjCmd --
+ *
+ *	This procedure is invoked to process the "chan postevent"
+ *	Tcl command. See the user documentation for details on what it does.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	Posts events to a reflected channel, invokes event handlers.
+ *	The latter implies that arbitrary side effects are possible.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclChanPostEventObjCmd (/*ignored*/ clientData, interp, objc, objv)
+     ClientData      clientData;
+     Tcl_Interp*     interp;
+     int             objc;
+     Tcl_Obj* CONST* objv;
+{
+    /* Syntax:   chan postevent CHANNEL EVENTSPEC
+     *           [0]  [1]       [2]     [3]
+     *
+     * Actually: rPostevent CHANNEL EVENTSPEC
+     *           [0]        [1]     [2]
+     *
+     *         where EVENTSPEC = {read write ...} (Abbreviations allowed as well.
+     */
+
+#define CHAN  (1)
+#define EVENT (2)
+
+    CONST char*        chanId;      /* Tcl level channel handle */
+    Tcl_Channel        chan;        /* Channel associated to the handle */
+    Tcl_ChannelType*   chanTypePtr; /* Its associated driver structure */
+    ReflectingChannel* rcPtr;       /* Associated instance data */
+    int                mode;        /* Dummy, r|w mode of the channel */
+    int                events;      /* Mask of events to post */
+
+    /* Number of arguments ... */
+
+    if (objc != 3) {
+        Tcl_WrongNumArgs(interp, 1, objv, "channel eventspec");
+	return TCL_ERROR;
+    }
+
+    /* First argument is a channel, a reflected channel, and the call
+     * of this command is done from the interp defining the channel
+     * handler cmd.
+     */
+
+    chanId = Tcl_GetString (objv [CHAN]);
+    chan   = Tcl_GetChannel(interp, chanId, &mode);
+
+    if (chan == (Tcl_Channel) NULL) {
+        return TCL_ERROR;
+    }
+
+    chanTypePtr = Tcl_GetChannelType (chan);
+
+    /* We use a function referenced by the channel type as our cookie
+     * to detect calls to non-reflecting channels. The channel type
+     * itself is not suitable, as it might not be the static
+     * definition in this file, but a clone thereof. And while we have
+     * reserved the name of the type nothing in the core checks
+     * against violation, so someone else might have created a channel
+     * type using our name, clashing with ourselves.
+     */
+
+    if (chanTypePtr->watchProc != &RcWatch) {
+        Tcl_AppendResult(interp, "channel \"", chanId,
+			 "\" is not a reflected channel",
+			 (char *) NULL);
+	return TCL_ERROR;
+    }
+
+    rcPtr = (ReflectingChannel*) Tcl_GetChannelInstanceData (chan);
+
+    if (rcPtr->interp != interp) {
+        Tcl_AppendResult(interp, "postevent for channel \"", chanId,
+			 "\" called from outside interpreter",
+			 (char *) NULL);
+	return TCL_ERROR;
+    }
+
+    /* Second argument is a list of events. Allowed entries are
+     * "read", "write". Expect at least one list element.
+     * Abbreviations are ok.
+     */
+
+    if (RcEncodeEventMask (interp, "event", objv [EVENT], &events) != TCL_OK) {
+        return TCL_ERROR;
+    }
+    
+    /* Check that the channel is actually interested in the provided
+     * events.
+     */
+
+    if (events & ~rcPtr->interest) {
+        Tcl_AppendResult(interp, "tried to post events channel \"", chanId,
+			 "\" is not interested in",
+			 (char *) NULL);
+	return TCL_ERROR;
+    }
+
+    /* We have the channel and the events to post.
+     */
+
+    Tcl_NotifyChannel (chan, events);
+
+    /* Squash interp results left by the event script.
+     */
+
+    Tcl_ResetResult (interp);
+    return TCL_OK;
+
+#undef CHAN
+#undef EVENT
+}
+
+
+static Tcl_Obj*
+RcErrorMarshall (interp)
+     Tcl_Interp *interp;
+{
+    /* Capture the result status of the interpreter into a string.
+     * => List of options and values, followed by the error message.
+     * The result has refCount 0.
+     */
+    
+    Tcl_Obj* returnOpt = Tcl_GetReturnOptions (interp, TCL_ERROR);
+
+    /* => returnOpt.refCount == 0. We can append directly.
+     */
+
+    Tcl_ListObjAppendElement (NULL, returnOpt, Tcl_GetObjResult (interp));
+    return returnOpt;
+}
+
+static void
+RcErrorReturn (interp, msg)
+     Tcl_Interp *interp;
+     Tcl_Obj    *msg;
+{
+    int       res;
+    int       lc;
+    Tcl_Obj** lv;
+    int       explicitResult;
+    int       numOptions;
+
+    /* Process the caught message.
+     *
+     * Syntax = (option value)... ?message?
+     *
+     * Bad syntax causes a panic. Because the other side uses
+     * Tcl_GetReturnOptions and list construction functions to marshall the
+     * information.
+     */
+
+    res = Tcl_ListObjGetElements (interp, msg, &lc, &lv);
+    if (res != TCL_OK) {
+	Tcl_Panic ("TclChanCaughtErrorBypass: Bad syntax of caught result");
+    }
+
+    explicitResult = (1 == (lc % 2));
+    numOptions     = lc - explicitResult;
+
+    if (explicitResult) {
+	Tcl_SetObjResult (interp, lv [lc-1]);
+    }
+
+    (void) Tcl_SetReturnOptions(interp, Tcl_NewListObj (numOptions, lv));
+}
+
+int
+TclChanCaughtErrorBypass (interp, chan)
+     Tcl_Interp *interp;
+     Tcl_Channel chan;
+{
+    Tcl_Obj* msgc = NULL;
+    Tcl_Obj* msgi = NULL;
+    Tcl_Obj* msg  = NULL;
+
+    /* Get a bypassed error message from channel and/or interpreter, save the
+     * reference, then kill the returned objects, if there were any. If there
+     * are messages in both the channel has preference.
+     */
+
+    if ((chan == NULL) && (interp == NULL)) {
+	return 0;
+    }
+
+    if (chan != NULL) {
+	Tcl_GetChannelError       (chan,   &msgc);
+    }
+    if (interp != NULL) {
+	Tcl_GetChannelErrorInterp (interp, &msgi);
+    }
+
+    if (msgc != NULL) {
+	msg = msgc;
+	Tcl_IncrRefCount (msg);
+    } else if (msgi != NULL) {
+	msg = msgi;
+	Tcl_IncrRefCount (msg);
+    }
+
+    if (msgc != NULL) {
+	Tcl_DecrRefCount (msgc);
+    }
+    if (msgi != NULL) {
+	Tcl_DecrRefCount (msgi);
+    }
+
+    /* No message returned, nothing caught.
+     */
+
+    if (msg == NULL) {
+	return 0;
+    }
+
+    RcErrorReturn (interp, msg);
+
+    Tcl_DecrRefCount (msg);
+    return 1;
+}
+
+/*
+ * Driver functions. ================================================
+ */
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * RcClose --
+ *
+ *	This function is invoked when the channel is closed, to delete
+ *	the driver specific instance data.
+ *
+ * Results:
+ *	A posix error.
+ *
+ * Side effects:
+ *	Releases memory. Arbitrary, as it calls upon a script.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+RcClose (clientData, interp)
+     ClientData  clientData;
+     Tcl_Interp* interp;
+{
+    ReflectingChannel* rcPtr = (ReflectingChannel*) clientData;
+    int                res;         /* Result code for 'close' */
+    Tcl_Obj*           resObj;      /* Result data for 'close' */
+
+    if (interp == (Tcl_Interp*) NULL) {
+        /* This call comes from TclFinalizeIOSystem. There are no
+	 * interpreters, and therefore we cannot call upon the handler
+	 * command anymore. Threading is irrelevant as well.  We
+	 * simply clean up all our C level data structures and leave
+	 * the Tcl level to the other finalization functions.
+	 */
+
+      /* THREADED => Forward this to the origin thread */
+      /* Note: Have a thread delete handler for the origin
+       * thread. Use this to clean up the structure!
+       */
+
+#ifdef TCL_THREADS
+        /* Are we in the correct thread ?
+	 */
+
+        if (rcPtr->thread != Tcl_GetCurrentThread ()) {
+	    RcForwardParamClose p;
+
+	    RcForwardOp (rcPtr, RcOpClose, rcPtr->thread, &p);
+	    res = p.b.code;
+
+	    /* RcFree is done in the forwarded operation!,
+	     * in the other thread. rcPtr here is gone!
+	     */
+
+	    if (res != TCL_OK) {
+	        RcFreeReceivedError (p.b);
+	    }
+	} else {
+#endif
+	    RcFree (rcPtr);
+#ifdef TCL_THREADS
+	}
+#endif
+	return EOK;
+    }
+
+    /* -------- */
+
+    /* -- No -- ASSERT rcPtr->methods & FLAG (METH_FINAL) */
+
+    /* A cleaned method mask here implies that the channel creation
+     * was aborted, and "finalize" must not be called.
+     */
+
+    if (rcPtr->methods == 0) {
+        RcFree (rcPtr);
+        return EOK;
+    } else {
+#ifdef TCL_THREADS
+        /* Are we in the correct thread ?
+	 */
+
+        if (rcPtr->thread != Tcl_GetCurrentThread ()) {
+	    RcForwardParamClose p;
+
+	    RcForwardOp (rcPtr, RcOpClose, rcPtr->thread, &p);
+	    res = p.b.code;
+
+	    /* RcFree is done in the forwarded operation!,
+	     * in the other thread. rcPtr here is gone!
+	     */
+
+	    if (res != TCL_OK) {
+	        RcPassReceivedErrorInterp (interp, p.b);
+	    }
+	} else {
+#endif
+	    RcInvokeTclMethod (rcPtr, "finalize", NULL, NULL,
+			       &res, &resObj, DO_CAPTURE);
+
+	    if ((res != TCL_OK) && (interp != NULL)) {
+	        Tcl_SetChannelErrorInterp (interp, resObj);
+	    }
+
+	    Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+#ifdef TCL_THREADS
+	    RcFree (rcPtr);
+	}
+#endif
+	return (res == TCL_OK) ? EOK : EINVAL;
+    }
+
+    Tcl_Panic ("Should not be reached");
+    return EINVAL;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * RcInput --
+ *
+ *	This function is invoked when more data is requested from the
+ *	channel.
+ *
+ * Results:
+ *	The number of bytes read.
+ *
+ * Side effects:
+ *	Allocates memory. Arbitrary, as it calls upon a script.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+RcInput (clientData, buf, toRead, errorCodePtr)
+     ClientData clientData;
+     char* buf;
+     int toRead;
+     int* errorCodePtr;
+{
+    ReflectingChannel* rcPtr = (ReflectingChannel*) clientData;
+    Tcl_Obj*           toReadObj;
+    int                bytec;       /* Number of returned bytes */
+    unsigned char*     bytev;       /* Array of returned bytes */
+    int                res;         /* Result code for 'read' */
+    Tcl_Obj*           resObj;      /* Result data for 'read' */
+
+    /* The following check can be done before thread redirection,
+     * because we are reading from an item which is readonly, i.e.
+     * will never change during the lifetime of the channel.
+     */
+
+    if (!(rcPtr->methods & FLAG (METH_READ))) {
+        RcSetChannelErrorStr (rcPtr->chan, msg_read_unsup);
+	*errorCodePtr = EINVAL;
+	return -1;
+    }
+
+#ifdef TCL_THREADS
+    /* Are we in the correct thread ?
+     */
+
+    if (rcPtr->thread != Tcl_GetCurrentThread ()) {
+        RcForwardParamInput p;
+
+	p.buf    = buf;
+	p.toRead = toRead;
+
+	RcForwardOp (rcPtr, RcOpInput, rcPtr->thread, &p);
+
+	if (p.b.code != TCL_OK) {
+	    RcPassReceivedError (rcPtr->chan, p.b);
+	    *errorCodePtr = EINVAL;
+	} else {
+	    *errorCodePtr = EOK;
+	}
+
+	return p.toRead;
+    }
+#endif
+
+    /* -------- */
+
+    /* ASSERT: rcPtr->method & FLAG (METH_READ) */
+    /* ASSERT: rcPtr->mode & TCL_READABLE */
+
+    toReadObj = Tcl_NewIntObj(toRead);
+    if (toReadObj == (Tcl_Obj*) NULL) {
+        Tcl_Panic ("Out of memory in RcInput");
+    }
+
+    RcInvokeTclMethod (rcPtr, "read", toReadObj, NULL,
+		       &res, &resObj, DO_CAPTURE);
+
+    if (res != TCL_OK) {
+	Tcl_SetChannelError (rcPtr->chan, resObj);
+        Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+	*errorCodePtr = EINVAL;
+	return -1;
+    }
+
+    bytev = Tcl_GetByteArrayFromObj(resObj, &bytec);
+
+    if (toRead < bytec) {
+        Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+	RcSetChannelErrorStr (rcPtr->chan, msg_read_toomuch);
+	*errorCodePtr = EINVAL;
+	return -1;
+    }
+
+    *errorCodePtr = EOK;
+
+    if (bytec > 0) {
+        memcpy (buf, bytev, bytec);
+    }
+
+    Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+    return bytec;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * RcOutput --
+ *
+ *	This function is invoked when data is writen to the
+ *	channel.
+ *
+ * Results:
+ *	The number of bytes actually written.
+ *
+ * Side effects:
+ *	Allocates memory. Arbitrary, as it calls upon a script.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+RcOutput (clientData, buf, toWrite, errorCodePtr)
+     ClientData clientData;
+     CONST char* buf;
+     int toWrite;
+     int* errorCodePtr;
+{
+    ReflectingChannel* rcPtr = (ReflectingChannel*) clientData;
+    Tcl_Obj*       bufObj;
+    int            res;         /* Result code for 'write' */
+    Tcl_Obj*       resObj;      /* Result data for 'write' */
+    int            written;
+
+    /* The following check can be done before thread redirection,
+     * because we are reading from an item which is readonly, i.e.
+     * will never change during the lifetime of the channel.
+     */
+
+    if (!(rcPtr->methods & FLAG (METH_WRITE))) {
+        RcSetChannelErrorStr (rcPtr->chan, msg_write_unsup);
+        *errorCodePtr = EINVAL;
+	return -1;
+    }
+
+#ifdef TCL_THREADS
+    /* Are we in the correct thread ?
+     */
+
+    if (rcPtr->thread != Tcl_GetCurrentThread ()) {
+      RcForwardParamOutput p;
+
+      p.buf     = buf;
+      p.toWrite = toWrite;
+
+      RcForwardOp (rcPtr, RcOpOutput, rcPtr->thread, &p);
+
+      if (p.b.code != TCL_OK) {
+	  RcPassReceivedError (rcPtr->chan, p.b);
+	  *errorCodePtr = EINVAL;
+      } else {
+	  *errorCodePtr = EOK;
+      }
+
+      return p.toWrite;
+    }
+#endif
+
+    /* -------- */
+
+    /* ASSERT: rcPtr->method & FLAG (METH_WRITE) */
+    /* ASSERT: rcPtr->mode & TCL_WRITABLE */
+    
+    bufObj = Tcl_NewByteArrayObj((unsigned char*) buf, toWrite);
+    if (bufObj == (Tcl_Obj*) NULL) {
+        Tcl_Panic ("Out of memory in RcOutput");
+    }
+
+    RcInvokeTclMethod (rcPtr, "write", bufObj, NULL,
+		       &res, &resObj, DO_CAPTURE);
+
+    if (res != TCL_OK) {
+	Tcl_SetChannelError (rcPtr->chan, resObj);
+	Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+	*errorCodePtr = EINVAL;
+	return -1;
+    }
+
+    res = Tcl_GetIntFromObj (rcPtr->interp, resObj, &written);
+    if (res != TCL_OK) {
+        Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+	Tcl_SetChannelError (rcPtr->chan, RcErrorMarshall (rcPtr->interp));
+	*errorCodePtr = EINVAL;
+	return -1;
+    }
+
+    Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+
+    if ((written == 0) || (toWrite < written)) {
+        /* The handler claims to have written more than it was given.
+	 * That is bad. Note that the I/O core would crash if we were
+	 * to return this information, trying to write -nnn bytes in
+	 * the next iteration.
+	 */
+
+        RcSetChannelErrorStr (rcPtr->chan, msg_write_toomuch);
+	*errorCodePtr = EINVAL;
+	return -1;
+    }
+
+    *errorCodePtr = EOK;
+    return written;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * RcSeekWide / RcSeek --
+ *
+ *	This function is invoked when the user wishes to seek on
+ *	the channel.
+ *
+ * Results:
+ *	The new location of the access point.
+ *
+ * Side effects:
+ *	Allocates memory. Arbitrary, as it calls upon a script.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static Tcl_WideInt
+RcSeekWide (clientData, offset, seekMode, errorCodePtr)
+     ClientData  clientData;
+     Tcl_WideInt offset;
+     int         seekMode;
+     int*        errorCodePtr;
+{
+    ReflectingChannel* rcPtr = (ReflectingChannel*) clientData;
+    Tcl_Obj*       offObj;
+    Tcl_Obj*       baseObj;
+    int            res;         /* Result code for 'seek' */
+    Tcl_Obj*       resObj;      /* Result data for 'seek' */
+    Tcl_WideInt    newLoc;
+
+#ifdef TCL_THREADS
+    /* Are we in the correct thread ?
+     */
+
+    if (rcPtr->thread != Tcl_GetCurrentThread ()) {
+        RcForwardParamSeek p;
+
+	p.seekMode = seekMode;
+	p.offset   = offset;
+
+	RcForwardOp (rcPtr, RcOpSeek, rcPtr->thread, &p);
+
+	if (p.b.code != TCL_OK) {
+	    RcPassReceivedError (rcPtr->chan, p.b);
+	    *errorCodePtr = EINVAL;
+	} else {
+	    *errorCodePtr = EOK;
+	}
+
+	return p.offset;
+    }
+#endif
+
+    /* -------- */
+
+    /* ASSERT: rcPtr->method & FLAG (METH_SEEK) */
+
+    offObj = Tcl_NewWideIntObj(offset);
+    if (offObj == (Tcl_Obj*) NULL) {
+        Tcl_Panic ("Out of memory in RcSeekWide");
+    }
+
+    baseObj = Tcl_NewStringObj((seekMode == SEEK_SET) ?
+			       "start" :
+			       ((seekMode == SEEK_CUR) ?
+				"current" :
+				"end"), -1);
+
+    if (baseObj == (Tcl_Obj*) NULL) {
+        Tcl_Panic ("Out of memory in RcSeekWide");
+    }
+
+    RcInvokeTclMethod (rcPtr, "seek", offObj, baseObj,
+		       &res, &resObj, DO_CAPTURE);
+
+    if (res != TCL_OK) {
+	Tcl_SetChannelError (rcPtr->chan, resObj);
+        Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+	*errorCodePtr = EINVAL;
+	return -1;
+    }
+
+    res = Tcl_GetWideIntFromObj (rcPtr->interp, resObj, &newLoc);
+    if (res != TCL_OK) {
+        Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+	Tcl_SetChannelError (rcPtr->chan, RcErrorMarshall (rcPtr->interp));
+	*errorCodePtr = EINVAL;
+	return -1;
+    }
+
+    Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+
+    if (newLoc < Tcl_LongAsWide (0)) {
+        RcSetChannelErrorStr (rcPtr->chan, msg_seek_beforestart);
+        *errorCodePtr = EINVAL;
+	return -1;
+    }
+
+    *errorCodePtr = EOK;
+    return newLoc;
+}
+
+static int
+RcSeek (clientData, offset, seekMode, errorCodePtr)
+     ClientData  clientData;
+     long        offset;
+     int         seekMode;
+     int*        errorCodePtr;
+{
+  /* This function can be invoked from a transformation which is based
+   * on standard seeking, i.e. non-wide. Because o this we have to
+   * implement it, a dummy is not enough. We simply delegate the call
+   * to the wide routine.
+   */
+
+  return (int) RcSeekWide (clientData, Tcl_LongAsWide (offset),
+			   seekMode, errorCodePtr);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * RcWatch --
+ *
+ *	This function is invoked to tell the channel what events
+ *	the I/O system is interested in.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Allocates memory. Arbitrary, as it calls upon a script.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+RcWatch (clientData, mask)
+     ClientData clientData;
+     int mask;
+{
+    ReflectingChannel* rcPtr = (ReflectingChannel*) clientData;
+    Tcl_Obj* maskObj;
+
+    /* ASSERT rcPtr->methods & FLAG (METH_WATCH) */
+
+    /* We restrict the interest to what the channel can support
+     * IOW there will never be write events for a channel which is
+     * not writable. Analoguous for read events.
+     */
+
+    mask = mask & rcPtr->mode; 
+
+    if (mask == rcPtr->interest) {
+        /* Same old, same old, why should we do something ? */
+      return;
+    }
+
+    rcPtr->interest = mask;
+
+#ifdef TCL_THREADS
+    /* Are we in the correct thread ?
+     */
+
+    if (rcPtr->thread != Tcl_GetCurrentThread ()) {
+        RcForwardParamWatch p;
+
+	p.mask = mask;
+
+	RcForwardOp (rcPtr, RcOpWatch, rcPtr->thread, &p);
+
+	/* Any failure from the forward is ignored. We have no place to
+	 * put this.
+	 */
+	return;
+    }
+#endif
+
+    /* -------- */
+
+    maskObj = RcDecodeEventMask (mask);
+    RcInvokeTclMethod (rcPtr, "watch", maskObj, NULL,
+		       NULL, NULL, NO_CAPTURE);
+    Tcl_DecrRefCount (maskObj);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * RcBlock --
+ *
+ *	This function is invoked to tell the channel which blocking
+ *	behaviour is required of it.
+ *
+ * Results:
+ *	A posix error number.
+ *
+ * Side effects:
+ *	Allocates memory. Arbitrary, as it calls upon a script.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+RcBlock (clientData, nonblocking)
+     ClientData clientData;
+     int nonblocking;
+{
+    ReflectingChannel* rcPtr = (ReflectingChannel*) clientData;
+    Tcl_Obj*           blockObj;
+    int                res;         /* Result code for 'blocking' */
+    Tcl_Obj*           resObj;      /* Result data for 'blocking' */
+
+#ifdef TCL_THREADS
+    /* Are we in the correct thread ?
+     */
+
+    if (rcPtr->thread != Tcl_GetCurrentThread ()) {
+        RcForwardParamBlock p;
+
+	p.nonblocking = nonblocking;
+
+	RcForwardOp (rcPtr, RcOpBlock, rcPtr->thread, &p);
+
+	if (p.b.code != TCL_OK) {
+	    RcPassReceivedError (rcPtr->chan, p.b);
+	    return EINVAL;
+	} else {
+	    return EOK;
+	}
+    }
+#endif
+
+    /* -------- */
+
+    blockObj = Tcl_NewBooleanObj(!nonblocking);
+    if (blockObj == (Tcl_Obj*) NULL) {
+        Tcl_Panic ("Out of memory in RcBlock");
+    }
+
+    RcInvokeTclMethod (rcPtr, "blocking", blockObj, NULL,
+		       &res, &resObj, DO_CAPTURE);
+
+    if (res != TCL_OK) {
+	Tcl_SetChannelError (rcPtr->chan, resObj);
+	res = EINVAL;
+    } else {
+        res = EOK;
+    }
+
+    Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+    return res;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * RcSetOption --
+ *
+ *	This function is invoked to configure a channel option.
+ *
+ * Results:
+ *	A standard Tcl result code.
+ *
+ * Side effects:
+ *	Arbitrary, as it calls upon a Tcl script.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+RcSetOption (clientData, interp, optionName, newValue)
+     ClientData   clientData;	/* Channel to query */
+     Tcl_Interp   *interp;	/* Interpreter to leave error messages in */
+     CONST char *optionName;	/* Name of requested option */
+     CONST char *newValue;	/* The new value */
+{
+    ReflectingChannel* rcPtr = (ReflectingChannel*) clientData;
+    Tcl_Obj*           optionObj;
+    Tcl_Obj*           valueObj;
+    int                res;         /* Result code for 'configure' */
+    Tcl_Obj*           resObj;      /* Result data for 'configure' */
+
+#ifdef TCL_THREADS
+    /* Are we in the correct thread ?
+     */
+
+    if (rcPtr->thread != Tcl_GetCurrentThread ()) {
+        RcForwardParamSetOpt p;
+
+	p.name  = optionName;
+	p.value = newValue;
+
+	RcForwardOp (rcPtr, RcOpSetOpt, rcPtr->thread, &p);
+
+	if (p.b.code != TCL_OK) {
+	    Tcl_Obj* err = Tcl_NewStringObj (p.b.msg, -1);
+
+	    RcErrorReturn (interp, err);
+
+	    Tcl_DecrRefCount (err);
+	    if (p.b.vol) {ckfree (p.b.msg);}
+	}
+
+	return p.b.code;
+    }
+#endif
+
+  /* -------- */
+
+  optionObj = Tcl_NewStringObj(optionName,-1);
+  if (optionObj == (Tcl_Obj*) NULL) {
+    Tcl_Panic ("Out of memory in RcSetOption");
+  }
+
+  valueObj = Tcl_NewStringObj(newValue,-1);
+  if (valueObj == (Tcl_Obj*) NULL) {
+    Tcl_Panic ("Out of memory in RcSetOption");
+  }
+
+  RcInvokeTclMethod (rcPtr, "configure", optionObj, valueObj,
+		     &res, &resObj, DO_CAPTURE);
+
+  if (res != TCL_OK) {
+    RcErrorReturn (interp, resObj);
+  }
+
+  Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+  return res;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * RcGetOption --
+ *
+ *	This function is invoked to retrieve all or a channel option.
+ *
+ * Results:
+ *	A standard Tcl result code.
+ *
+ * Side effects:
+ *	Arbitrary, as it calls upon a Tcl script.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+RcGetOption (clientData, interp, optionName, dsPtr)
+     ClientData   clientData;	/* Channel to query */
+     Tcl_Interp*  interp;	/* Interpreter to leave error messages in */
+     CONST char* optionName;	/* Name of reuqested option */
+     Tcl_DString* dsPtr;	/* String to place the result into */
+{
+    /* This code is special. It has regular passing of Tcl result, and
+     * errors. The bypass functions are not required.
+     */
+
+    ReflectingChannel* rcPtr = (ReflectingChannel*) clientData;
+    Tcl_Obj*           optionObj;
+    int                res;         /* Result code for 'configure' */
+    Tcl_Obj*           resObj;      /* Result data for 'configure' */
+    int                listc;
+    Tcl_Obj**          listv;
+    const char*        method;
+
+#ifdef TCL_THREADS
+    /* Are we in the correct thread ?
+     */
+
+    if (rcPtr->thread != Tcl_GetCurrentThread ()) {
+        int opcode;
+        RcForwardParamGetOpt p;
+
+	p.name  = optionName;
+	p.value = dsPtr;
+
+	if (optionName == (char*) NULL) {
+	    opcode = RcOpGetOptAll;
+	} else {
+	    opcode = RcOpGetOpt;
+	}
+
+	RcForwardOp (rcPtr, opcode, rcPtr->thread, &p);
+
+	if (p.b.code != TCL_OK) {
+	    Tcl_Obj* err = Tcl_NewStringObj (p.b.msg, -1);
+
+	    RcErrorReturn (interp, err);
+
+	    Tcl_DecrRefCount (err);
+	    if (p.b.vol) {ckfree (p.b.msg);}
+	}
+
+	return p.b.code;
+    }
+#endif
+
+    /* -------- */
+
+    if (optionName == (char*) NULL) {
+        /* Retrieve all options. */
+        method    = "cgetall";
+	optionObj = NULL;
+    } else {
+        /* Retrieve the value of one option */
+      
+        method    = "cget";
+	optionObj = Tcl_NewStringObj(optionName,-1);
+	if (optionObj == (Tcl_Obj*) NULL) {
+	    Tcl_Panic ("Out of memory in RcGetOption");
+	}
+    }
+
+    RcInvokeTclMethod (rcPtr, method, optionObj, NULL,
+			 &res, &resObj, DO_CAPTURE);
+
+    if (res != TCL_OK) {
+        RcErrorReturn (interp, resObj);
+	Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+	return res;
+    }
+
+    /* The result has to go into the 'dsPtr' for propagation to the
+     * caller of the driver.
+     */
+
+    if (optionObj != NULL) {
+        Tcl_DStringAppend (dsPtr, Tcl_GetString (resObj), -1);
+	Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+	return res;
+    }
+
+    /* Extract the list and append each item as element.
+     */
+
+    /* NOTE (4): If we extract the string rep we can assume a
+     * NOTE (4): properly quoted string. Together with a separating
+     * NOTE (4): space this way of simply appending the whole string
+     * NOTE (4): rep might be faster. It also doesn't check if the
+     * NOTE (4): result is a valid list. Nor that the list has an
+     * NOTE (4): even number elements.
+     * NOTE (4): ---
+     */
+
+    res = Tcl_ListObjGetElements (interp, resObj, &listc, &listv);
+
+    if (res != TCL_OK) {
+        Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+	return res;
+    }
+
+    if ((listc % 2) == 1) {
+        /* Odd number of elements is wrong.
+	 */
+
+        char buf [20];
+
+	sprintf (buf, "%d", listc);
+	Tcl_ResetResult  (interp);
+	Tcl_AppendResult (interp,
+			  "Expected list with even number of elements, got ",
+			  buf, (listc == 1 ? " element" : " elements"),
+			  " instead", (char*) NULL);
+
+	Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+	return TCL_ERROR;
+    }
+
+
+    {
+        int len;
+	char* str = Tcl_GetStringFromObj (resObj, &len);
+
+	if (len) {
+	    Tcl_DStringAppend (dsPtr, " ", 1);
+	    Tcl_DStringAppend (dsPtr, str, len);
+	}
+    }
+    Tcl_DecrRefCount (resObj); /* Remove reference we held from the invoke */
+    return res;
+}
+
+/*
+ * Helpers. =========================================================
+ */
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * RcEncodeEventMask --
+ *
+ *	This function takes a list of event items and constructs the
+ *	equivalent internal bitmask. The list has to contain at
+ *	least one element. Elements are "read", "write", or any unique
+ *	abbreviation thereof. Note that the bitmask is not changed if
+ *	problems are encountered.
+ *
+ * Results:
+ *	A standard Tcl error code. A bitmask where TCL_READABLE
+ *	and/or TCL_WRITABLE can be set.
+ *
+ * Side effects:
+ *	May shimmer 'obj' to a list representation. May place an
+ *	error message into the interp result.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+RcEncodeEventMask (interp, objName, obj, mask)
+     Tcl_Interp* interp;
+     CONST char* objName;
+     Tcl_Obj*    obj;
+     int*        mask;
+{
+    int        events;	/* Mask of events to post */
+    int        listc;     /* #elements in eventspec list */
+    Tcl_Obj**  listv;     /* Elements of eventspec list */
+    int        evIndex;   /* Id of event for an element of the
+			 * eventspec list */
+
+    if (Tcl_ListObjGetElements (interp, obj,
+				&listc, &listv) != TCL_OK) {
+        return TCL_ERROR;
+    }
+
+    if (listc < 1) {
+        Tcl_AppendResult(interp, "bad ", objName, " list: is empty",
+			 (char *) NULL);
+	return TCL_ERROR;
+    }
+
+    events = 0;
+    while (listc > 0) {
+        if (Tcl_GetIndexFromObj (interp, listv [listc-1],
+				 eventOptions, objName, 0, &evIndex) != TCL_OK) {
+	    return TCL_ERROR;
+	}
+	switch (evIndex) {
+	    case EVENT_READ:  events |= TCL_READABLE; break;
+	    case EVENT_WRITE: events |= TCL_WRITABLE; break;
+	}
+	listc --;
+    }
+
+    *mask = events;
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * RcDecodeEventMask --
+ *
+ *	This function takes an internal bitmask of events and
+ *	constructs the equivalent list of event items.
+ *
+ * Results:
+ *	A Tcl_Obj reference. The object will have a refCount of
+ *	one. The user has to decrement it to release the object.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static Tcl_Obj*
+RcDecodeEventMask (mask)
+{
+    Tcl_Obj* evObj = Tcl_NewStringObj (((mask & RANDW) == RANDW) ?
+				       "read write" :
+				       ((mask & TCL_READABLE) ?
+					"read" :
+					((mask & TCL_WRITABLE) ?
+					 "write" : "")), -1);
+    if (evObj == (Tcl_Obj*) NULL) {
+        Tcl_Panic ("Out of memory in RcDecodeEventMask");
+    }
+
+    Tcl_IncrRefCount (evObj);
+    return evObj;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * RcNew --
+ *
+ *	This function is invoked to allocate and initialize the
+ *	instance data of a new reflected channel.
+ *
+ * Results:
+ *	A heap-allocated channel instance.
+ *
+ * Side effects:
+ *	Allocates memory.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static ReflectingChannel*
+RcNew (interp, cmdpfxObj, mode, id)
+       Tcl_Interp* interp;
+       Tcl_Obj*    cmdpfxObj;
+       int         mode;
+       Tcl_Obj*    id;
+{
+    ReflectingChannel* rcPtr;
+    int                listc;
+    Tcl_Obj**          listv;
+    Tcl_Obj*           word;
+    int                i;
+
+    rcPtr = (ReflectingChannel*) ckalloc (sizeof(ReflectingChannel));
+
+    /* rcPtr->chan    : Assigned by caller. Dummy data here. */
+    /* rcPtr->methods : Assigned by caller. Dummy data here. */
+
+    rcPtr->chan     = (Tcl_Channel) NULL;
+    rcPtr->methods  = 0;
+    rcPtr->interp   = interp;
+#ifdef TCL_THREADS
+    rcPtr->thread   = Tcl_GetCurrentThread ();
+#endif
+    rcPtr->mode     = mode;
+    rcPtr->interest = 0; /* Initially no interest registered */
+
+    /* Method placeholder */
+
+    /* ASSERT: cmdpfxObj is a Tcl List */
+
+    Tcl_ListObjGetElements (interp, cmdpfxObj, &listc, &listv);
+
+    /* See [==] as well.
+     * Storage for the command prefix and the additional words required
+     * for the invocation of methods in the command handler.
+     *
+     * listv [0] [listc-1] | [listc]  [listc+1] |
+     * argv  [0]   ... [.] | [argc-2] [argc-1]  | [argc]  [argc+2]
+     *       cmd   ... pfx | method   chan      | detail1 detail2
+     */
+
+    rcPtr->argc = listc + 2;
+    rcPtr->argv = (Tcl_Obj**) ckalloc (sizeof (Tcl_Obj*) * (listc+4));
+
+    for (i = 0; i < listc ; i++) {
+        word = rcPtr->argv [i] = listv [i];
+        Tcl_IncrRefCount (word);
+    }
+
+    i++; /* Skip placeholder for method */
+
+    rcPtr->argv [i] = id ; Tcl_IncrRefCount (id);
+
+    /* The next two objects are kept empty, varying arguments */
+
+    /* Initialization complete */
+    return rcPtr;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * RcNewHandle --
+ *
+ *	This function is invoked to generate a channel handle for
+ *	a new reflected channel.
+ *
+ * Results:
+ *	A Tcl_Obj containing the string of the new channel handle.
+ *	The refcount of the returned object is -- zero --.
+ *
+ * Side effects:
+ *	May allocate memory. Mutex protected critical section
+ *	locks out other threads for a short time.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Obj*
+RcNewHandle ()
+{
+    /* Count number of generated reflected channels.  Used for id
+     * generation. Ids are never reclaimed and there is no dealing
+     * with wrap around. On the other hand, "unsigned long" should be
+     * big enough except for absolute longrunners (generate a 100 ids
+     * per second => overflow will occur in 1 1/3 years).
+     */
+
+#ifdef TCL_THREADS
+    TCL_DECLARE_MUTEX (rcCounterMutex)
+#endif
+    static unsigned long rcCounter = 0;
+
+    char     channelName [50];
+    Tcl_Obj* res = Tcl_NewStringObj ("rc", -1);
+
+#ifdef TCL_THREADS
+    Tcl_MutexLock (&rcCounterMutex);
+#endif
+
+    sprintf (channelName, "%lu", (unsigned long) rcCounter);
+    rcCounter ++;
+
+#ifdef TCL_THREADS
+    Tcl_MutexUnlock (&rcCounterMutex);
+#endif
+
+    Tcl_AppendStringsToObj (res, channelName, (char*) NULL);
+    return res;
+}
+
+
+static void
+RcFree (rcPtr)
+     ReflectingChannel* rcPtr;
+{
+    Channel* chanPtr = (Channel*) rcPtr->chan;
+    int      i, n;
+
+    if (chanPtr->typePtr != &tclRChannelType) {
+        /* Delete a cloned ChannelType structure. */
+        ckfree ((char*) chanPtr->typePtr);
+    }
+
+    n = rcPtr->argc - 2;
+    for (i = 0; i < n; i++) {
+        Tcl_DecrRefCount (rcPtr->argv[i]);
+    }
+
+    ckfree ((char*) rcPtr->argv);
+    ckfree ((char*) rcPtr);
+    return;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * RcInvokeTclMethod --
+ *
+ *	This function is used to invoke the Tcl level of a reflected
+ *	channel. It handles all the command assembly, invokation, and
+ *	generic state and result mgmt.
+ *
+ * Results:
+ *      Result code and data as returned by the method.
+ *
+ * Side effects:
+ *	Arbitrary, as it calls upo na Tcl script.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+RcInvokeTclMethod (rcPtr, method, argone, argtwo, result, resultObj, capture)
+     ReflectingChannel* rcPtr;
+     CONST char*        method;
+     Tcl_Obj*           argone;    /* NULL'able */
+     Tcl_Obj*           argtwo;    /* NULL'able */
+     int*               result;    /* NULL'able */
+     Tcl_Obj**          resultObj; /* NULL'able */
+     int                capture;
+{
+    /* Thread redirection was done by higher layers */
+    /* ASSERT: Tcl_GetCurrentThread () == rcPtr->thread */
+
+    int             cmdc;           /* #words in constructed command */
+    Tcl_Obj*        methObj = NULL; /* Method name in object form */
+    Tcl_InterpState sr;             /* State of handler interp */
+    int             res;            /* Result code of method invokation */
+    Tcl_Obj*        resObj  = NULL; /* Result of method invokation. */
+
+    /* NOTE (5): Decide impl. issue: Cache objects with method names ?
+     * NOTE (5): Requires TSD data as reflections can be created in
+     * NOTE (5): many different threads.
+     * NOTE (5): ---
+     */
+
+    /* Insert method into the pre-allocated area, after the command
+     * prefix, before the channel id.
+     */
+
+    methObj = Tcl_NewStringObj (method, -1);
+    if (methObj == (Tcl_Obj*) NULL) {
+        Tcl_Panic ("Out of memory in RcInvokeTclMethod");
+    }
+    Tcl_IncrRefCount (methObj);
+    rcPtr->argv [rcPtr->argc - 2] = methObj;
+
+    /* Append the additional argument containing method specific
+     * details behind the channel id. If specified.
+     */
+
+    cmdc = rcPtr->argc ;
+    if (argone) {
+        Tcl_IncrRefCount (argone);
+	rcPtr->argv [cmdc] = argone;
+	cmdc++;
+    }
+    if (argtwo) {
+        Tcl_IncrRefCount (argtwo);
+	rcPtr->argv [cmdc] = argtwo;
+	cmdc++;
+    }
+
+    /* And run the handler ...  This is done in auch a manner which
+     * leaves any existing state intact.
+     */
+
+    sr  = Tcl_SaveInterpState (rcPtr->interp, 0 /* Dummy */);
+    res = Tcl_EvalObjv        (rcPtr->interp, cmdc, rcPtr->argv, TCL_EVAL_GLOBAL);
+
+    /* We do not try to extract the result information if the caller has no
+     * interest in it. I.e. there is no need to put effort into creating
+     * something which is discarded immediately after.
+     */
+
+    if (resultObj) {
+	if ((res == TCL_OK) || !capture) {
+	    /* Ok result taken as is, also if the caller requests that there
+	     * is no capture.
+	     */
+
+	    resObj = Tcl_GetObjResult (rcPtr->interp);
+	} else {
+	    /* Non-ok ressult is always treated as an error.
+	     * We have to capture the full state of the result,
+	     * including additional options.
+	     */
+
+	    res    = TCL_ERROR;
+	    resObj = RcErrorMarshall (rcPtr->interp);
+	}
+	Tcl_IncrRefCount(resObj);
+    }
+    Tcl_RestoreInterpState (rcPtr->interp, sr);
+
+    /* ... */
+
+    /* Cleanup of the dynamic parts of the command */
+
+    Tcl_DecrRefCount (methObj);
+    if (argone) {Tcl_DecrRefCount (argone);}
+    if (argtwo) {Tcl_DecrRefCount (argtwo);}
+
+    /* The resObj has a ref count of 1 at this location.  This means
+     * that the caller of RcInvoke has to dispose of it (but only if
+     * it was returned to it).
+     */
+
+    if (result) {
+        *result = res;
+    }
+    if (resultObj) {
+        *resultObj = resObj;
+    }
+    /* There no need to handle the case where nothing is returned, because for
+     * that case resObj was not set anyway.
+     */
+}
+
+#ifdef TCL_THREADS
+static void
+RcForwardOp (rcPtr, op, dst, param)
+  ReflectingChannel* rcPtr; /* Channel instance */
+  RcOperation        op;    /* Forwarded driver operation */
+  Tcl_ThreadId       dst;   /* Destination thread */
+  CONST VOID*        param; /* Arguments */
+{
+    RcForwardingEvent*  evPtr;
+    RcForwardingResult* resultPtr;
+    int                 result;
+
+    /* Create and initialize the event and data structures */
+
+    evPtr     = (RcForwardingEvent*)  ckalloc (sizeof (RcForwardingEvent));
+    resultPtr = (RcForwardingResult*) ckalloc (sizeof (RcForwardingResult));
+
+    evPtr->event.proc = RcForwardProc;
+    evPtr->resultPtr  = resultPtr;
+    evPtr->op         = op;
+    evPtr->rcPtr      = rcPtr;
+    evPtr->param      = param;
+
+    resultPtr->src    = Tcl_GetCurrentThread ();
+    resultPtr->dst    = dst;
+    resultPtr->done   = (Tcl_Condition) NULL;
+    resultPtr->result = -1;
+    resultPtr->evPtr  = evPtr;
+
+    /* Now execute the forward */
+
+    Tcl_MutexLock(&rcForwardMutex);
+    TclSpliceIn(resultPtr, forwardList);
+
+    /*
+     * Ensure cleanup of the event if any of the two involved threads
+     * exits while this event is pending or in progress.
+     */
+
+    Tcl_CreateThreadExitHandler(RcSrcExitProc, (ClientData) evPtr);
+    Tcl_CreateThreadExitHandler(RcDstExitProc, (ClientData) evPtr);
+
+    /*
+     * Queue the event and poke the other thread's notifier.
+     */
+
+    Tcl_ThreadQueueEvent(dst, (Tcl_Event*)evPtr, TCL_QUEUE_TAIL);
+    Tcl_ThreadAlert(dst);
+
+    /*
+     * (*) Block until the other thread has either processed the transfer
+     * or rejected it.
+     */
+
+    while (resultPtr->result < 0) {
+        /* NOTE (1): Is it possible that the current thread goes away while waiting here ?
+	 * NOTE (1): IOW Is it possible that "RcSrcExitProc" is called while we are here ?
+	 * NOTE (1): See complementary note (2) in "RcSrcExitProc"
+	 * NOTE (1): ---
+	 */
+
+        Tcl_ConditionWait(&resultPtr->done, &rcForwardMutex, NULL);
+    }
+
+    /*
+     * Unlink result from the forwarder list.
+     */
+
+    TclSpliceOut(resultPtr, forwardList);
+
+    resultPtr->nextPtr  = NULL;
+    resultPtr->prevPtr  = NULL;
+
+    Tcl_MutexUnlock(&rcForwardMutex);
+    Tcl_ConditionFinalize(&resultPtr->done);
+
+    /*
+     * Kill the cleanup handlers now, and the result structure as well,
+     * before returning the success code.
+     *
+     * Note: The event structure has already been deleted.
+     */
+
+    Tcl_DeleteThreadExitHandler(RcSrcExitProc, (ClientData) evPtr);
+    Tcl_DeleteThreadExitHandler(RcDstExitProc, (ClientData) evPtr);
+    
+    result =  resultPtr->result;
+    ckfree ((char*) resultPtr);
+}
+
+static int
+RcForwardProc (evGPtr, mask)
+     Tcl_Event *evGPtr; 
+     int mask;
+{
+    /* Notes regarding access to the referenced data.
+     *
+     * In principle the data belongs to the originating thread (see
+     * evPtr->src), however this thread is currently blocked at (*),
+     * i.e. quiescent. Because of this we can treat the data as
+     * belonging to us, without fear of race conditions. I.e. we can
+     * read and write as we like.
+     *
+     * The only thing we cannot be sure of is the resultPtr. This can be
+     * be NULLed if the originating thread went away while the event
+     * is handled here now.
+     */
+
+    RcForwardingEvent*  evPtr     = (RcForwardingEvent*) evGPtr;
+    RcForwardingResult* resultPtr = evPtr->resultPtr;
+    ReflectingChannel*  rcPtr     = evPtr->rcPtr;
+    Tcl_Interp*         interp    = rcPtr->interp;
+    RcForwardParamBase* paramPtr  = (RcForwardParamBase*) evPtr->param;
+    int                 res       = TCL_OK; /* Result code   of RcInvokeTclMethod */
+    Tcl_Obj*            resObj    = NULL;   /* Interp result of RcInvokeTclMethod */
+
+    /* Ignore the event if no one is waiting for its result anymore.
+     */
+
+    if (!resultPtr) {
+        return 1;
+    }
+
+    paramPtr->code = TCL_OK;
+    paramPtr->msg  = NULL;
+    paramPtr->vol  = 0;
+
+    switch (evPtr->op) {
+      /* The destination thread for the following operations is
+       * rcPtr->thread, which contains rcPtr->interp, the interp
+       * we have to call upon for the driver.
+       */
+
+    case RcOpClose:
+      {
+	  /* No parameters/results */
+	  RcInvokeTclMethod (rcPtr, "finalize", NULL, NULL,
+			     &res, &resObj, DO_CAPTURE);
+
+	  if (res != TCL_OK) {
+	     RcForwardSetObjError (paramPtr, resObj);
+	  }
+
+	  /* Freeing is done here, in the origin thread, because the
+	   * argv[] objects belong to this thread. Deallocating them
+	   * in a different thread is not allowed
+	   */
+
+	  RcFree (rcPtr);
+      }
+      break;
+
+    case RcOpInput:
+      {
+	  RcForwardParamInput* p = (RcForwardParamInput*) paramPtr;
+	  Tcl_Obj*     toReadObj = Tcl_NewIntObj (p->toRead);
+
+	  if (toReadObj == (Tcl_Obj*) NULL) {
+	      Tcl_Panic ("Out of memory in RcInput");
+	  }
+
+	  RcInvokeTclMethod (rcPtr, "read", toReadObj, NULL,
+			     &res, &resObj, DO_CAPTURE);
+
+	  if (res != TCL_OK) {
+	      RcForwardSetObjError (paramPtr, resObj);
+	      p->toRead = -1;
+	  } else {
+	      /* Process a regular result. */
+
+	      int            bytec; /* Number of returned bytes */
+	      unsigned char* bytev; /* Array of returned bytes */
+
+	      bytev = Tcl_GetByteArrayFromObj(resObj, &bytec);
+
+	      if (p->toRead < bytec) {
+		  RcForwardSetStaticError (paramPtr, msg_read_toomuch);
+		  p->toRead   = -1;
+
+	      } else {
+	          if (bytec > 0) {
+		      memcpy (p->buf, bytev, bytec);
+		  }
+
+		  p->toRead = bytec;
+	      }
+	  }
+      }
+      break;
+
+    case RcOpOutput:
+      {
+	  RcForwardParamOutput* p = (RcForwardParamOutput*) paramPtr;
+	  Tcl_Obj*         bufObj = Tcl_NewByteArrayObj((unsigned char*) p->buf, p->toWrite);
+
+	  if (bufObj == (Tcl_Obj*) NULL) {
+	      Tcl_Panic ("Out of memory in RcOutput");
+	  }
+
+	  RcInvokeTclMethod (rcPtr, "write", bufObj, NULL,
+			     &res, &resObj, DO_CAPTURE);
+
+	  if (res != TCL_OK) {
+	      RcForwardSetObjError (paramPtr, resObj);
+	      p->toWrite = -1;
+	  } else {
+	      /* Process a regular result. */
+
+	      int written;
+
+	      res = Tcl_GetIntFromObj (interp, resObj, &written);
+	      if (res != TCL_OK) {
+
+		  RcForwardSetObjError (paramPtr, RcErrorMarshall (interp));
+		  p->toWrite = -1;
+
+	      } else if ((written == 0) || (p->toWrite < written)) {
+
+		  RcForwardSetStaticError (paramPtr, msg_write_toomuch);
+		  p->toWrite = -1;
+
+	      } else {
+		  p->toWrite = written;
+	      }
+	  }
+      }
+      break;
+
+    case RcOpSeek:
+      {
+	  RcForwardParamSeek* p = (RcForwardParamSeek*) paramPtr;
+
+	  Tcl_Obj*       offObj;
+	  Tcl_Obj*       baseObj;
+
+	  offObj = Tcl_NewWideIntObj(p->offset);
+	  if (offObj == (Tcl_Obj*) NULL) {
+	      Tcl_Panic ("Out of memory in RcSeekWide");
+	  }
+
+	  baseObj = Tcl_NewStringObj((p->seekMode == SEEK_SET) ?
+				     "start" :
+				     ((p->seekMode == SEEK_CUR) ?
+				      "current" :
+				      "end"), -1);
+
+	  if (baseObj == (Tcl_Obj*) NULL) {
+	      Tcl_Panic ("Out of memory in RcSeekWide");
+	  }
+
+	  RcInvokeTclMethod (rcPtr, "seek", offObj, baseObj,
+			     &res, &resObj, DO_CAPTURE);
+
+	  if (res != TCL_OK) {
+	      RcForwardSetObjError (paramPtr, resObj);
+	      p->offset = -1;
+	  } else {
+	      /* Process a regular result. If the type is wrong this
+	       * may change into an error.
+	       */
+
+	      Tcl_WideInt newLoc;
+	      res = Tcl_GetWideIntFromObj (interp, resObj, &newLoc);
+
+	      if (res == TCL_OK) {
+		  if (newLoc < Tcl_LongAsWide (0)) {
+		      RcForwardSetStaticError (paramPtr, msg_seek_beforestart);
+		      p->offset = -1;
+		  } else {
+		      p->offset = newLoc;
+		  }
+	      } else {
+		  RcForwardSetObjError (paramPtr, RcErrorMarshall (interp));
+		  p->offset = -1;
+	      }
+	  }
+      }
+      break;
+
+    case RcOpWatch:
+      {
+	  RcForwardParamWatch* p = (RcForwardParamWatch*) paramPtr;
+
+	  Tcl_Obj* maskObj = RcDecodeEventMask (p->mask);
+	  RcInvokeTclMethod (rcPtr, "watch", maskObj, NULL,
+			     NULL, NULL, NO_CAPTURE);
+	  Tcl_DecrRefCount (maskObj);
+      }
+    break;
+
+    case RcOpBlock:
+      {
+	  RcForwardParamBlock* p = (RcForwardParamBlock*) evPtr->param;
+	  Tcl_Obj*      blockObj = Tcl_NewBooleanObj(!p->nonblocking);
+
+	  if (blockObj == (Tcl_Obj*) NULL) {
+	      Tcl_Panic ("Out of memory in RcBlock");
+	  }
+
+	  RcInvokeTclMethod (rcPtr, "blocking", blockObj, NULL,
+			     &res, &resObj, DO_CAPTURE);
+
+	  if (res != TCL_OK) {
+	      RcForwardSetObjError (paramPtr, resObj);
+	  }
+      }
+      break;
+
+    case RcOpSetOpt:
+      {
+	  RcForwardParamSetOpt* p = (RcForwardParamSetOpt*) paramPtr;
+	  Tcl_Obj* optionObj;
+	  Tcl_Obj* valueObj;
+
+	  optionObj = Tcl_NewStringObj(p->name,-1);
+	  if (optionObj == (Tcl_Obj*) NULL) {
+	      Tcl_Panic ("Out of memory in RcSetOption");
+	  }
+
+	  valueObj = Tcl_NewStringObj(p->value,-1);
+	  if (valueObj == (Tcl_Obj*) NULL) {
+	      Tcl_Panic ("Out of memory in RcSetOption");
+	  }
+
+	  RcInvokeTclMethod (rcPtr, "configure", optionObj, valueObj,
+			     &res, &resObj, DO_CAPTURE);
+
+	  if (res != TCL_OK) {
+	      RcForwardSetObjError (paramPtr, resObj);
+	  }
+      }
+      break;
+
+    case RcOpGetOpt:
+      {
+	  /* Retrieve the value of one option */
+
+	  RcForwardParamGetOpt* p = (RcForwardParamGetOpt*) paramPtr;
+	  Tcl_Obj*           optionObj;
+
+	  optionObj = Tcl_NewStringObj(p->name,-1);
+	  if (optionObj == (Tcl_Obj*) NULL) {
+	      Tcl_Panic ("Out of memory in RcGetOption");
+	  }
+
+	  RcInvokeTclMethod (rcPtr, "cget", optionObj, NULL,
+			     &res, &resObj, DO_CAPTURE);
+
+	  if (res != TCL_OK) {
+	      RcForwardSetObjError (paramPtr, resObj);
+	  } else {
+	      Tcl_DStringAppend (p->value, Tcl_GetString (resObj), -1);
+	  }
+      }
+      break;
+
+    case RcOpGetOptAll:
+      {
+	  /* Retrieve all options. */
+
+	  RcForwardParamGetOpt* p = (RcForwardParamGetOpt*) paramPtr;
+
+	  RcInvokeTclMethod (rcPtr, "cgetall", NULL, NULL,
+			     &res, &resObj, DO_CAPTURE);
+
+	  if (res != TCL_OK) {
+	      RcForwardSetObjError (paramPtr, resObj);
+	  } else {
+	      /* Extract list, validate that it is a list, and
+	       * #elements. See NOTE (4) as well.
+	       */
+
+	      int       listc;
+	      Tcl_Obj** listv;
+
+	      res = Tcl_ListObjGetElements (interp, resObj, &listc, &listv);
+	      if (res != TCL_OK) {
+		  RcForwardSetObjError (paramPtr, RcErrorMarshall (interp));
+
+	      } else if ((listc % 2) == 1) {
+	          /* Odd number of elements is wrong.
+		   * [x].
+		   */
+
+	          char* buf = ckalloc (200);
+		  sprintf (buf,
+			   "{Expected list with even number of elements, got %d %s instead}",
+			   listc,
+			   (listc == 1 ? "element" : "elements"));
+		  
+		  RcForwardSetDynError (paramPtr, buf);
+	      } else {
+		  int len;
+		  char* str = Tcl_GetStringFromObj (resObj, &len);
+
+		  if (len) {
+		      Tcl_DStringAppend (p->value, " ", 1);
+		      Tcl_DStringAppend (p->value, str, len);
+		  }
+	      }
+	  }
+      }
+      break;
+
+    default:
+      /* Bad operation code */
+      Tcl_Panic ("Bad operation code in RcForwardProc");
+      break;
+    }
+
+    /* Remove the reference we held on the result of the invoke, if we had
+     * such
+     */
+    if (resObj != NULL) {
+	Tcl_DecrRefCount (resObj);
+    }
+
+    if (resultPtr) {
+        /*
+	 * Report the forwarding result synchronously to the waiting
+	 * caller. This unblocks (*) as well. This is wrapped into a
+	 * conditional because the caller may have exited in the mean
+	 * time.
+	 */
+
+        Tcl_MutexLock(&rcForwardMutex);
+	resultPtr->result = TCL_OK;
+	Tcl_ConditionNotify(&resultPtr->done);
+	Tcl_MutexUnlock(&rcForwardMutex);
+    }
+
+    return 1;
+}
+
+
+static void
+RcSrcExitProc (clientData)
+     ClientData clientData;
+{
+  RcForwardingEvent*  evPtr = (RcForwardingEvent*) clientData;
+  RcForwardingResult* resultPtr;
+  RcForwardParamBase* paramPtr;
+
+  /* NOTE (2): Can this handler be called with the originator blocked ?
+   * NOTE (2): ---
+   */
+
+  /* The originator for the event exited. It is not sure if this
+   * can happen, as the originator should be blocked at (*) while
+   * the event is in transit/pending.
+   */
+
+  /*
+   * We make sure that the event cannot refer to the result anymore,
+   * remove it from the list of pending results and free the
+   * structure. Locking the access ensures that we cannot get in
+   * conflict with "RcForwardProc", should it already execute the
+   * event.
+   */
+
+  Tcl_MutexLock(&rcForwardMutex);
+
+  resultPtr = evPtr->resultPtr;
+  paramPtr  = (RcForwardParamBase*) evPtr->param;
+
+  evPtr->resultPtr  = NULL;
+  resultPtr->evPtr  = NULL;
+  resultPtr->result = TCL_ERROR;
+
+  RcForwardSetStaticError (paramPtr, msg_send_originlost);
+
+  /* See below: TclSpliceOut(resultPtr, forwardList); */
+
+  Tcl_MutexUnlock(&rcForwardMutex);
+
+  /*
+   * This unlocks (*). The structure will be spliced out and freed by
+   * "RcForwardProc". Maybe.
+   */
+
+  Tcl_ConditionNotify(&resultPtr->done);
+}
+
+
+static void
+RcDstExitProc (clientData)
+     ClientData clientData;
+{
+  RcForwardingEvent*  evPtr     = (RcForwardingEvent*) clientData;
+  RcForwardingResult* resultPtr = evPtr->resultPtr;
+  RcForwardParamBase* paramPtr  = (RcForwardParamBase*) evPtr->param;
+
+  /* NOTE (3): It is not clear if the event still exists when this handler is called..
+   * NOTE (3): We might have to use 'resultPtr' as our clientData instead.
+   * NOTE (3): ---
+   */
+
+  /* The receiver for the event exited, before processing the
+   * event. We detach the result now, wake the originator up
+   * and signal failure.
+   */
+
+  evPtr->resultPtr = NULL;
+  resultPtr->evPtr  = NULL;
+  resultPtr->result = TCL_ERROR;
+
+  RcForwardSetStaticError (paramPtr, msg_send_dstlost);
+
+  Tcl_ConditionNotify(&resultPtr->done);
+}
+
+
+static void
+RcForwardSetObjError (p,obj)
+     RcForwardParamBase* p;
+     Tcl_Obj*            obj;
+{
+    int   len;
+    char* msg;
+
+    msg = Tcl_GetStringFromObj (obj, &len);
+
+    p->code = TCL_ERROR;
+    p->vol  = 1;
+    p->msg  = strcpy(ckalloc (1+len), msg);
+}
+#endif
+
+/*
+ * Local Variables:
+ * mode: c
+ * c-basic-offset: 4
+ * fill-column: 78
+ * End:
+ */