Initial revision

1 files changed, 3834 insertions, 0 deletions

diff --git a/generic/tclInterp.c b/generic/tclInterp.c
new file mode 100644
index 0000000..6cf3f66
--- /dev/null
+++ b/generic/tclInterp.c
@@ -0,0 +1,3834 @@
+/* 
+ * tclInterp.c --
+ *
+ *	This file implements the "interp" command which allows creation
+ *	and manipulation of Tcl interpreters from within Tcl scripts.
+ *
+ * Copyright (c) 1995-1997 Sun Microsystems, Inc.
+ *
+ * See the file "license.terms" for information on usage and redistribution
+ * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+ *
+ * SCCS: @(#) tclInterp.c 1.128 97/11/05 09:35:12
+ */
+
+#include <stdio.h>
+#include "tclInt.h"
+#include "tclPort.h"
+
+/*
+ * Counter for how many aliases were created (global)
+ */
+
+static int aliasCounter = 0;
+
+/*
+ *
+ * struct Slave:
+ *
+ * Used by the "interp" command to record and find information about slave
+ * interpreters. Maps from a command name in the master to information about
+ * a slave interpreter, e.g. what aliases are defined in it.
+ */
+
+typedef struct {
+    Tcl_Interp *masterInterp;	/* Master interpreter for this slave. */
+    Tcl_HashEntry *slaveEntry;	/* Hash entry in masters slave table for
+                                 * this slave interpreter. Used to find
+                                 * this record, and used when deleting the
+                                 * slave interpreter to delete it from the
+                                 * masters table. */
+    Tcl_Interp	*slaveInterp;	/* The slave interpreter. */
+    Tcl_Command interpCmd;	/* Interpreter object command. */
+    Tcl_HashTable aliasTable;	/* Table which maps from names of commands
+                                 * in slave interpreter to struct Alias
+                                 * defined below. */
+} Slave;
+
+/*
+ * struct Alias:
+ *
+ * Stores information about an alias. Is stored in the slave interpreter
+ * and used by the source command to find the target command in the master
+ * when the source command is invoked.
+ */
+
+typedef struct {
+    char	*aliasName;	/* Name of alias command. */
+    char	*targetName;	/* Name of target command in master interp. */
+    Tcl_Interp	*targetInterp;	/* Master interpreter. */
+    int		objc;		/* Count of additional args to pass. */
+    Tcl_Obj	**objv;		/* Actual additional args to pass. */
+    Tcl_HashEntry *aliasEntry;	/* Entry for the alias hash table in slave.
+                                 * This is used by alias deletion to remove
+                                 * the alias from the slave interpreter
+                                 * alias table. */
+    Tcl_HashEntry *targetEntry;	/* Entry for target command in master.
+                                 * This is used in the master interpreter to
+                                 * map back from the target command to aliases
+                                 * redirecting to it. Random access to this
+                                 * hash table is never required - we are using
+                                 * a hash table only for convenience. */
+    Tcl_Command slaveCmd;	/* Source command in slave interpreter. */
+} Alias;
+
+/*
+ * struct Target:
+ *
+ * Maps from master interpreter commands back to the source commands in slave
+ * interpreters. This is needed because aliases can be created between sibling
+ * interpreters and must be deleted when the target interpreter is deleted. In
+ * case they would not be deleted the source interpreter would be left with a
+ * "dangling pointer". One such record is stored in the Master record of the
+ * master interpreter (in the targetTable hashtable, see below) with the
+ * master for each alias which directs to a command in the master. These
+ * records are used to remove the source command for an from a slave if/when
+ * the master is deleted.
+ */
+
+typedef struct {
+    Tcl_Command	slaveCmd;	/* Command for alias in slave interp. */
+    Tcl_Interp *slaveInterp;	/* Slave Interpreter. */
+} Target;
+
+/*
+ * struct Master:
+ *
+ * This record is used for two purposes: First, slaveTable (a hashtable)
+ * maps from names of commands to slave interpreters. This hashtable is
+ * used to store information about slave interpreters of this interpreter,
+ * to map over all slaves, etc. The second purpose is to store information
+ * about all aliases in slaves (or siblings) which direct to target commands
+ * in this interpreter (using the targetTable hashtable).
+ * 
+ * NB: the flags field in the interp structure, used with SAFE_INTERP
+ * mask denotes whether the interpreter is safe or not. Safe
+ * interpreters have restricted functionality, can only create safe slave
+ * interpreters and can only load safe extensions.
+ */
+
+typedef struct {
+    Tcl_HashTable slaveTable;	/* Hash table for slave interpreters.
+                                 * Maps from command names to Slave records. */
+    Tcl_HashTable targetTable;	/* Hash table for Target Records. Contains
+                                 * all Target records which denote aliases
+                                 * from slaves or sibling interpreters that
+                                 * direct to commands in this interpreter. This
+                                 * table is used to remove dangling pointers
+                                 * from the slave (or sibling) interpreters
+                                 * when this interpreter is deleted. */
+} Master;
+
+/*
+ * Prototypes for local static procedures:
+ */
+
+static int		AliasCmd _ANSI_ARGS_((ClientData dummy,
+			    Tcl_Interp *currentInterp, int objc,
+		            Tcl_Obj *CONST objv[]));
+static void		AliasCmdDeleteProc _ANSI_ARGS_((
+			    ClientData clientData));
+static int		AliasCreationHelper _ANSI_ARGS_((Tcl_Interp *curInterp,
+			    Tcl_Interp *slaveInterp, Tcl_Interp *masterInterp,
+			    Master *masterPtr, char *aliasName,
+			    char *targetName, int objc,
+			    Tcl_Obj *CONST objv[]));
+static int		CreateInterpObject _ANSI_ARGS_((Tcl_Interp *interp,
+			    Master *masterPtr, int objc,
+        		    Tcl_Obj *CONST objv[]));
+static Tcl_Interp	*CreateSlave _ANSI_ARGS_((Tcl_Interp *interp,
+		            Master *masterPtr, char *slavePath, int safe));
+static int		DeleteAlias _ANSI_ARGS_((Tcl_Interp *interp,
+			    Tcl_Interp *slaveInterp, char *aliasName));
+static int		DescribeAlias _ANSI_ARGS_((Tcl_Interp *interp,
+			    Tcl_Interp *slaveInterp, char *aliasName));
+static int		DeleteInterpObject _ANSI_ARGS_((Tcl_Interp *interp,
+			    Master *masterPtr, int objc,
+        		    Tcl_Obj *CONST objv[]));
+static int		DeleteOneInterpObject _ANSI_ARGS_((Tcl_Interp *interp,
+			    Master *masterPtr, char *path));
+static Tcl_Interp	*GetInterp _ANSI_ARGS_((Tcl_Interp *interp,
+			    Master *masterPtr, char *path,
+			    Master **masterPtrPtr));
+static int		GetTarget _ANSI_ARGS_((Tcl_Interp *interp, char *path,
+			    char *aliasName));
+static int		InterpAliasHelper _ANSI_ARGS_((Tcl_Interp *interp,
+		            Master *masterPtr, int objc,
+        		    Tcl_Obj *CONST objv[]));
+static int		InterpAliasesHelper _ANSI_ARGS_((Tcl_Interp *interp,
+		            Master *masterPtr, int objc,
+        		    Tcl_Obj *CONST objv[]));
+static int		InterpExistsHelper _ANSI_ARGS_((Tcl_Interp *interp,
+			    Master *masterPtr, int objc,
+        		    Tcl_Obj *CONST objv[]));
+static int		InterpEvalHelper _ANSI_ARGS_((Tcl_Interp *interp,
+			    Master *masterPtr, int objc,
+        		    Tcl_Obj *CONST objv[]));
+static int		InterpExposeHelper _ANSI_ARGS_((Tcl_Interp *interp,
+			    Master *masterPtr, int objc,
+        		    Tcl_Obj *CONST objv[]));
+static int		InterpIsSafeHelper _ANSI_ARGS_((Tcl_Interp *interp,
+			    Master *masterPtr, int objc,
+        		    Tcl_Obj *CONST objv[]));
+static int		InterpHideHelper _ANSI_ARGS_((Tcl_Interp *interp,
+			    Master *masterPtr, int objc,
+        		    Tcl_Obj *CONST objv[]));
+static int		InterpHiddenHelper _ANSI_ARGS_((Tcl_Interp *interp,
+			    Master *masterPtr, int objc,
+        		    Tcl_Obj *CONST objv[]));
+static int		InterpInvokeHiddenHelper _ANSI_ARGS_((
+    			    Tcl_Interp *interp, Master *masterPtr, int objc,
+        		    Tcl_Obj *CONST objv[]));
+static int		InterpMarkTrustedHelper _ANSI_ARGS_((
+    			    Tcl_Interp *interp, Master *masterPtr, int objc,
+        		    Tcl_Obj *CONST objv[]));
+static int		InterpSlavesHelper _ANSI_ARGS_((Tcl_Interp *interp,
+			    Master *masterPtr, int objc,
+        		    Tcl_Obj *CONST objv[]));
+static int		InterpShareHelper _ANSI_ARGS_((Tcl_Interp *interp,
+			    Master *masterPtr, int objc,
+        		    Tcl_Obj *CONST objv[]));
+static int		InterpTargetHelper _ANSI_ARGS_((Tcl_Interp *interp,
+			    Master *masterPtr, int objc,
+        		    Tcl_Obj *CONST objv[]));
+static int		InterpTransferHelper _ANSI_ARGS_((Tcl_Interp *interp,
+			    Master *masterPtr, int objc,
+        		    Tcl_Obj *CONST objv[]));
+static int		MarkTrusted _ANSI_ARGS_((Tcl_Interp *interp));
+static void		MasterRecordDeleteProc _ANSI_ARGS_((
+			    ClientData clientData, Tcl_Interp *interp));
+static int		SlaveAliasHelper _ANSI_ARGS_((Tcl_Interp *interp,
+		            Tcl_Interp *slaveInterp, Slave *slavePtr,
+		            int objc, Tcl_Obj *CONST objv[]));
+static int		SlaveAliasesHelper _ANSI_ARGS_((Tcl_Interp *interp,
+		            Tcl_Interp *slaveInterp, Slave *slavePtr,
+		            int objc, Tcl_Obj *CONST objv[]));
+static int		SlaveEvalHelper _ANSI_ARGS_((Tcl_Interp *interp,
+		            Tcl_Interp *slaveInterp, Slave *slavePtr,
+		            int objc, Tcl_Obj *CONST objv[]));
+static int		SlaveExposeHelper _ANSI_ARGS_((Tcl_Interp *interp,
+		            Tcl_Interp *slaveInterp, Slave *slavePtr,
+		            int objc, Tcl_Obj *CONST objv[]));
+static int		SlaveHideHelper _ANSI_ARGS_((Tcl_Interp *interp,
+		            Tcl_Interp *slaveInterp, Slave *slavePtr,
+		            int objc, Tcl_Obj *CONST objv[]));
+static int		SlaveHiddenHelper _ANSI_ARGS_((Tcl_Interp *interp,
+		            Tcl_Interp *slaveInterp, Slave *slavePtr,
+		            int objc, Tcl_Obj *CONST objv[]));
+static int		SlaveIsSafeHelper _ANSI_ARGS_((
+    			    Tcl_Interp *interp, Tcl_Interp *slaveInterp,
+                            Slave *slavePtr, int objc, Tcl_Obj *CONST objv[]));
+static int		SlaveInvokeHiddenHelper _ANSI_ARGS_((
+    			    Tcl_Interp *interp, Tcl_Interp *slaveInterp,
+                            Slave *slavePtr, int objc, Tcl_Obj *CONST objv[]));
+static int		SlaveMarkTrustedHelper _ANSI_ARGS_((Tcl_Interp *interp,
+		            Tcl_Interp *slaveInterp, Slave *slavePtr,
+		            int objc, Tcl_Obj *CONST objv[]));
+static int		SlaveObjectCmd _ANSI_ARGS_((ClientData dummy,
+			    Tcl_Interp *interp, int objc,
+			    Tcl_Obj *CONST objv[]));
+static void		SlaveObjectDeleteProc _ANSI_ARGS_((
+			    ClientData clientData));
+static void		SlaveRecordDeleteProc _ANSI_ARGS_((
+			    ClientData clientData, Tcl_Interp *interp));
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclPreventAliasLoop --
+ *
+ *	When defining an alias or renaming a command, prevent an alias
+ *	loop from being formed.
+ *
+ * Results:
+ *	A standard Tcl object result.
+ *
+ * Side effects:
+ *	If TCL_ERROR is returned, the function also stores an error message
+ *	in the interpreter's result object.
+ *
+ * NOTE:
+ *	This function is public internal (instead of being static to
+ *	this file) because it is also used from TclRenameCommand.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclPreventAliasLoop(interp, cmdInterp, cmd)
+    Tcl_Interp *interp;			/* Interp in which to report errors. */
+    Tcl_Interp *cmdInterp;		/* Interp in which the command is
+                                         * being defined. */
+    Tcl_Command cmd;                    /* Tcl command we are attempting
+                                         * to define. */
+{
+    Command *cmdPtr = (Command *) cmd;
+    Alias *aliasPtr, *nextAliasPtr;
+    Tcl_Command aliasCmd;
+    Command *aliasCmdPtr;
+    
+    /*
+     * If we are not creating or renaming an alias, then it is
+     * always OK to create or rename the command.
+     */
+    
+    if (cmdPtr->objProc != AliasCmd) {
+        return TCL_OK;
+    }
+
+    /*
+     * OK, we are dealing with an alias, so traverse the chain of aliases.
+     * If we encounter the alias we are defining (or renaming to) any in
+     * the chain then we have a loop.
+     */
+
+    aliasPtr = (Alias *) cmdPtr->objClientData;
+    nextAliasPtr = aliasPtr;
+    while (1) {
+
+        /*
+         * If the target of the next alias in the chain is the same as
+         * the source alias, we have a loop.
+	 */
+
+	aliasCmd = Tcl_FindCommand(nextAliasPtr->targetInterp,
+                nextAliasPtr->targetName,
+		Tcl_GetGlobalNamespace(nextAliasPtr->targetInterp),
+		/*flags*/ 0);
+        if (aliasCmd == (Tcl_Command) NULL) {
+            return TCL_OK;
+        }
+	aliasCmdPtr = (Command *) aliasCmd;
+        if (aliasCmdPtr == cmdPtr) {
+            Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+		"cannot define or rename alias \"", aliasPtr->aliasName,
+		"\": would create a loop", (char *) NULL);
+            return TCL_ERROR;
+        }
+
+        /*
+	 * Otherwise, follow the chain one step further. See if the target
+         * command is an alias - if so, follow the loop to its target
+         * command. Otherwise we do not have a loop.
+	 */
+
+        if (aliasCmdPtr->objProc != AliasCmd) {
+            return TCL_OK;
+        }
+        nextAliasPtr = (Alias *) aliasCmdPtr->objClientData;
+    }
+
+    /* NOTREACHED */
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * MarkTrusted --
+ *
+ *	Mark an interpreter as unsafe (i.e. remove the "safe" mark).
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	Removes the "safe" mark from an interpreter.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+MarkTrusted(interp)
+    Tcl_Interp *interp;		/* Interpreter to be marked unsafe. */
+{
+    Interp *iPtr = (Interp *) interp;
+
+    iPtr->flags &= ~SAFE_INTERP;
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_MakeSafe --
+ *
+ *	Makes its argument interpreter contain only functionality that is
+ *	defined to be part of Safe Tcl. Unsafe commands are hidden, the
+ *	env array is unset, and the standard channels are removed.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Hides commands in its argument interpreter, and removes settings
+ *	and channels.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_MakeSafe(interp)
+    Tcl_Interp *interp;		/* Interpreter to be made safe. */
+{
+    Tcl_Channel chan;				/* Channel to remove from
+                                                 * safe interpreter. */
+    Interp *iPtr = (Interp *) interp;
+
+    TclHideUnsafeCommands(interp);
+    
+    iPtr->flags |= SAFE_INTERP;
+
+    /*
+     *  Unsetting variables : (which should not have been set 
+     *  in the first place, but...)
+     */
+
+    /*
+     * No env array in a safe slave.
+     */
+
+    Tcl_UnsetVar(interp, "env", TCL_GLOBAL_ONLY);
+
+    /* 
+     * Remove unsafe parts of tcl_platform
+     */
+
+    Tcl_UnsetVar2(interp, "tcl_platform", "os", TCL_GLOBAL_ONLY);
+    Tcl_UnsetVar2(interp, "tcl_platform", "osVersion", TCL_GLOBAL_ONLY);
+    Tcl_UnsetVar2(interp, "tcl_platform", "machine", TCL_GLOBAL_ONLY);
+
+    /*
+     * Unset path informations variables
+     * (the only one remaining is [info nameofexecutable])
+     */
+
+    Tcl_UnsetVar(interp, "tcl_library", TCL_GLOBAL_ONLY);
+    Tcl_UnsetVar(interp, "tcl_pkgPath", TCL_GLOBAL_ONLY);
+    
+    /*
+     * Remove the standard channels from the interpreter; safe interpreters
+     * do not ordinarily have access to stdin, stdout and stderr.
+     *
+     * NOTE: These channels are not added to the interpreter by the
+     * Tcl_CreateInterp call, but may be added later, by another I/O
+     * operation. We want to ensure that the interpreter does not have
+     * these channels even if it is being made safe after being used for
+     * some time..
+     */
+
+    chan = Tcl_GetStdChannel(TCL_STDIN);
+    if (chan != (Tcl_Channel) NULL) {
+        Tcl_UnregisterChannel(interp, chan);
+    }
+    chan = Tcl_GetStdChannel(TCL_STDOUT);
+    if (chan != (Tcl_Channel) NULL) {
+        Tcl_UnregisterChannel(interp, chan);
+    }
+    chan = Tcl_GetStdChannel(TCL_STDERR);
+    if (chan != (Tcl_Channel) NULL) {
+        Tcl_UnregisterChannel(interp, chan);
+    }
+
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * GetInterp --
+ *
+ *	Helper function to find a slave interpreter given a pathname.
+ *
+ * Results:
+ *	Returns the slave interpreter known by that name in the calling
+ *	interpreter, or NULL if no interpreter known by that name exists. 
+ *
+ * Side effects:
+ *	Assigns to the pointer variable passed in, if not NULL.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static Tcl_Interp *
+GetInterp(interp, masterPtr, path, masterPtrPtr)
+    Tcl_Interp *interp;		/* Interp. to start search from. */
+    Master *masterPtr;		/* Its master record. */
+    char *path;			/* The path (name) of interp. to be found. */
+    Master **masterPtrPtr;	/* (Return) its master record. */
+{
+    Tcl_HashEntry *hPtr;	/* Search element. */
+    Slave *slavePtr;		/* Interim slave record. */
+    char **argv;		/* Split-up path (name) for interp to find. */
+    int argc, i;		/* Loop indices. */
+    Tcl_Interp *searchInterp;	/* Interim storage for interp. to find. */
+
+    if (masterPtrPtr != (Master **) NULL) {
+        *masterPtrPtr = masterPtr;
+    }
+    
+    if (Tcl_SplitList(interp, path, &argc, &argv) != TCL_OK) {
+        return (Tcl_Interp *) NULL;
+    }
+
+    for (searchInterp = interp, i = 0; i < argc; i++) {
+        
+        hPtr = Tcl_FindHashEntry(&(masterPtr->slaveTable), argv[i]);
+        if (hPtr == (Tcl_HashEntry *) NULL) {
+            ckfree((char *) argv);
+            return (Tcl_Interp *) NULL;
+        }
+        slavePtr = (Slave *) Tcl_GetHashValue(hPtr);
+        searchInterp = slavePtr->slaveInterp;
+        if (searchInterp == (Tcl_Interp *) NULL) {
+            ckfree((char *) argv);
+            return (Tcl_Interp *) NULL;
+        }
+        masterPtr = (Master *) Tcl_GetAssocData(searchInterp,
+                "tclMasterRecord", NULL);
+        if (masterPtrPtr != (Master **) NULL) *masterPtrPtr = masterPtr;
+        if (masterPtr == (Master *) NULL) {
+            ckfree((char *) argv);
+            return (Tcl_Interp *) NULL;
+        }
+    }
+    ckfree((char *) argv);
+    return searchInterp;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * CreateSlave --
+ *
+ *	Helper function to do the actual work of creating a slave interp
+ *	and new object command. Also optionally makes the new slave
+ *	interpreter "safe".
+ *
+ * Results:
+ *	Returns the new Tcl_Interp * if successful or NULL if not. If failed,
+ *	the result of the invoking interpreter contains an error message.
+ *
+ * Side effects:
+ *	Creates a new slave interpreter and a new object command.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static Tcl_Interp *
+CreateSlave(interp, masterPtr, slavePath, safe)
+    Tcl_Interp *interp;			/* Interp. to start search from. */
+    Master *masterPtr;			/* Master record. */
+    char *slavePath;			/* Path (name) of slave to create. */
+    int safe;				/* Should we make it "safe"? */
+{
+    Tcl_Interp *slaveInterp;		/* Ptr to slave interpreter. */
+    Tcl_Interp *masterInterp;		/* Ptr to master interp for slave. */
+    Slave *slavePtr;			/* Slave record. */
+    Tcl_HashEntry *hPtr;		/* Entry into interp hashtable. */
+    int new;				/* Indicates whether new entry. */
+    int argc;				/* Count of elements in slavePath. */
+    char **argv;			/* Elements in slavePath. */
+    char *masterPath;			/* Path to its master. */
+
+    if (Tcl_SplitList(interp, slavePath, &argc, &argv) != TCL_OK) {
+        return (Tcl_Interp *) NULL;
+    }
+
+    if (argc < 2) {
+        masterInterp = interp;
+        if (argc == 1) {
+            slavePath = argv[0];
+        }
+    } else {
+        masterPath = Tcl_Merge(argc-1, argv);
+        masterInterp = GetInterp(interp, masterPtr, masterPath, &masterPtr);
+        if (masterInterp == (Tcl_Interp *) NULL) {
+            Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                    "interpreter named \"", masterPath,
+                    "\" not found", (char *) NULL);
+            ckfree((char *) argv);
+            ckfree((char *) masterPath);
+            return (Tcl_Interp *) NULL;
+        }
+        ckfree((char *) masterPath);
+        slavePath = argv[argc-1];
+        if (!safe) {
+            safe = Tcl_IsSafe(masterInterp);
+        }
+    }
+    hPtr = Tcl_CreateHashEntry(&(masterPtr->slaveTable), slavePath, &new);
+    if (new == 0) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "interpreter named \"", slavePath,
+                "\" already exists, cannot create", (char *) NULL);
+        ckfree((char *) argv);
+        return (Tcl_Interp *) NULL;
+    }
+    slaveInterp = Tcl_CreateInterp();
+    if (slaveInterp == (Tcl_Interp *) NULL) {
+        panic("CreateSlave: out of memory while creating a new interpreter");
+    }
+    slavePtr = (Slave *) Tcl_GetAssocData(slaveInterp, "tclSlaveRecord", NULL);
+    slavePtr->masterInterp = masterInterp;
+    slavePtr->slaveEntry = hPtr;
+    slavePtr->slaveInterp = slaveInterp;
+    slavePtr->interpCmd = Tcl_CreateObjCommand(masterInterp, slavePath,
+            SlaveObjectCmd, (ClientData) slaveInterp, SlaveObjectDeleteProc);
+    Tcl_InitHashTable(&(slavePtr->aliasTable), TCL_STRING_KEYS);
+    (void) Tcl_SetAssocData(slaveInterp, "tclSlaveRecord",
+            SlaveRecordDeleteProc, (ClientData) slavePtr);
+    Tcl_SetHashValue(hPtr, (ClientData) slavePtr);
+    Tcl_SetVar(slaveInterp, "tcl_interactive", "0", TCL_GLOBAL_ONLY);
+    
+    /*
+     * Inherit the recursion limit.
+     */
+    ((Interp *)slaveInterp)->maxNestingDepth =
+	((Interp *)masterInterp)->maxNestingDepth ;
+
+    if (safe) {
+        if (Tcl_MakeSafe(slaveInterp) == TCL_ERROR) {
+            goto error;
+        }
+    } else {
+        if (Tcl_Init(slaveInterp) == TCL_ERROR) {
+            goto error;
+        }
+    }
+
+    ckfree((char *) argv);
+    return slaveInterp;
+
+error:
+
+    Tcl_AddErrorInfo(interp, Tcl_GetVar2(slaveInterp, "errorInfo", (char *)
+            NULL, TCL_GLOBAL_ONLY));
+    Tcl_SetVar2(interp, "errorCode", (char *) NULL,
+            Tcl_GetVar2(slaveInterp, "errorCode", (char *) NULL,
+                    TCL_GLOBAL_ONLY),
+            TCL_GLOBAL_ONLY);
+
+    Tcl_SetObjResult(interp, Tcl_GetObjResult(slaveInterp));
+    Tcl_ResetResult(slaveInterp);
+
+    (void) Tcl_DeleteCommand(masterInterp, slavePath);
+
+    ckfree((char *) argv);
+    return (Tcl_Interp *) NULL;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * CreateInterpObject -
+ *
+ *	Helper function to do the actual work of creating a new interpreter
+ *	and an object command. 
+ *
+ * Results:
+ *	A Tcl result.
+ *
+ * Side effects:
+ *	See user documentation for details.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+CreateInterpObject(interp, masterPtr, objc, objv)
+    Tcl_Interp *interp;			/* Invoking interpreter. */
+    Master *masterPtr;			/* Master record for same. */
+    int objc;				/* Number of arguments. */
+    Tcl_Obj *CONST objv[];		/* with alias. */
+{
+    int safe;				/* Create a safe interpreter? */
+    int moreFlags;			/* Expecting more flag args? */
+    char *string;			/* Local pointer to object string. */
+    char *slavePath;			/* Name of slave. */
+    char localSlaveName[200];		/* Local area for creating names. */
+    int i;				/* Loop counter. */
+    int len;				/* Length of option argument. */
+    static int interpCounter = 0;	/* Unique id for created names. */
+
+    moreFlags = 1;
+    slavePath = NULL;
+    safe = Tcl_IsSafe(interp);
+    
+    if ((objc < 2) || (objc > 5)) {
+        Tcl_WrongNumArgs(interp, 2, objv, "?-safe? ?--? ?path?");
+        return TCL_ERROR;
+    }
+    for (i = 2; i < objc; i++) {
+        string = Tcl_GetStringFromObj(objv[i], &len);
+        if ((string[0] == '-') && (moreFlags != 0)) {
+            if ((string[1] == 's') &&
+                (strncmp(string, "-safe", (size_t) len) == 0) &&
+                (len > 1)){
+                safe = 1;
+            } else if ((strncmp(string, "--", (size_t) len) == 0) &&
+                       (len > 1)) {
+                moreFlags = 0;
+            } else {
+                Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                        "bad option \"", string, "\": should be -safe",
+                        (char *) NULL);
+                return TCL_ERROR;
+            }
+        } else {
+            slavePath = string;
+        }
+    }
+    if (slavePath == (char *) NULL) {
+
+        /*
+         * Create an anonymous interpreter -- we choose its name and
+         * the name of the command. We check that the command name that
+         * we use for the interpreter does not collide with an existing
+         * command in the master interpreter.
+         */
+        
+        while (1) {
+            Tcl_CmdInfo cmdInfo;
+            
+            sprintf(localSlaveName, "interp%d", interpCounter);
+            interpCounter++;
+            if (!(Tcl_GetCommandInfo(interp, localSlaveName, &cmdInfo))) {
+                break;
+            }
+        }
+        slavePath = localSlaveName;
+    }
+    if (CreateSlave(interp, masterPtr, slavePath, safe) != NULL) {
+        Tcl_SetObjResult(interp, Tcl_NewStringObj(slavePath, -1));
+        return TCL_OK;
+    } else {
+        /*
+         * CreateSlave already set the result if there was an error,
+         * so we do not do it here.
+         */
+        return TCL_ERROR;
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * DeleteOneInterpObject --
+ *
+ *	Helper function for DeleteInterpObject. It deals with deleting one
+ *	interpreter at a time.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	Deletes an interpreter and its interpreter object command.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+DeleteOneInterpObject(interp, masterPtr, path)
+    Tcl_Interp *interp;			/* Interpreter for reporting errors. */
+    Master *masterPtr;			/* Interim storage for master record.*/
+    char *path;				/* Path of interpreter to delete. */
+{
+    Slave *slavePtr;			/* Interim storage for slave record. */
+    Tcl_Interp *masterInterp;		/* Master of interp. to delete. */
+    Tcl_HashEntry *hPtr;		/* Search element. */
+    int localArgc;			/* Local copy of count of elements in
+                                         * path (name) of interp. to delete. */
+    char **localArgv;			/* Local copy of path. */
+    char *slaveName;			/* Last component in path. */
+    char *masterPath;			/* One-before-last component in path.*/
+
+    if (Tcl_SplitList(interp, path, &localArgc, &localArgv) != TCL_OK) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "bad interpreter path \"", path, "\"", (char *) NULL);
+        return TCL_ERROR;
+    }
+    if (localArgc < 2) {
+        masterInterp = interp;
+        if (localArgc == 0) {
+            slaveName = "";
+        } else {
+            slaveName = localArgv[0];
+        }
+    } else {
+        masterPath = Tcl_Merge(localArgc-1, localArgv);
+        masterInterp = GetInterp(interp, masterPtr, masterPath, &masterPtr);
+        if (masterInterp == (Tcl_Interp *) NULL) {
+            Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                    "interpreter named \"", masterPath, "\" not found",
+                    (char *) NULL);
+            ckfree((char *) localArgv);
+            ckfree((char *) masterPath);
+            return TCL_ERROR;
+        }
+        ckfree((char *) masterPath);
+        slaveName = localArgv[localArgc-1];
+    }
+    hPtr = Tcl_FindHashEntry(&(masterPtr->slaveTable), slaveName);
+    if (hPtr == (Tcl_HashEntry *) NULL) {
+        ckfree((char *) localArgv);
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "interpreter named \"", path, "\" not found", (char *) NULL);
+        return TCL_ERROR;
+    }
+    slavePtr = (Slave *) Tcl_GetHashValue(hPtr);
+    if (Tcl_DeleteCommandFromToken(masterInterp, slavePtr->interpCmd) != 0) {
+        ckfree((char *) localArgv);
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "interpreter named \"", path, "\" not found", (char *) NULL);
+        return TCL_ERROR;
+    }
+    ckfree((char *) localArgv);
+
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * DeleteInterpObject --
+ *
+ *	Helper function to do the work of deleting zero or more
+ *	interpreters and their interpreter object commands.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	Deletes interpreters and their interpreter object command.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+DeleteInterpObject(interp, masterPtr, objc, objv)
+    Tcl_Interp *interp;			/* Interpreter start search from. */
+    Master *masterPtr;			/* Interim storage for master record.*/
+    int objc;				/* Number of arguments in vector. */
+    Tcl_Obj *CONST objv[];		/* with alias. */
+{
+    int i;
+    int len;
+    
+    for (i = 2; i < objc; i++) {
+        if (DeleteOneInterpObject(interp, masterPtr,
+                Tcl_GetStringFromObj(objv[i], &len))
+                != TCL_OK) {
+            return TCL_ERROR;
+        }
+    }
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * AliasCreationHelper --
+ *
+ *	Helper function to do the work to actually create an alias or
+ *	delete an alias.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	An alias command is created and entered into the alias table
+ *	for the slave interpreter.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+AliasCreationHelper(curInterp, slaveInterp, masterInterp, masterPtr,
+     aliasName, targetName, objc, objv)
+    Tcl_Interp *curInterp;		/* Interp that invoked this proc. */
+    Tcl_Interp *slaveInterp;		/* Interp where alias cmd will live
+                                         * or from which alias will be
+                                         * deleted. */
+    Tcl_Interp *masterInterp;		/* Interp where target cmd will be. */
+    Master *masterPtr;			/* Master record for target interp. */
+    char *aliasName;			/* Name of alias cmd. */
+    char *targetName;			/* Name of target cmd. */
+    int objc;				/* Additional arguments to store */
+    Tcl_Obj *CONST objv[];		/* with alias. */
+{
+    Alias *aliasPtr;			/* Storage for alias data. */
+    Alias *tmpAliasPtr;			/* Temp storage for alias to delete. */
+    Tcl_HashEntry *hPtr;		/* Entry into interp hashtable. */
+    int i;				/* Loop index. */
+    int new;				/* Is it a new hash entry? */
+    Target *targetPtr;			/* Maps from target command in master
+                                         * to source command in slave. */
+    Slave *slavePtr;			/* Maps from source command in slave
+                                         * to target command in master. */
+
+    slavePtr = (Slave *) Tcl_GetAssocData(slaveInterp, "tclSlaveRecord", NULL);
+
+    /*
+     * Slave record should be always present because it is created when
+     * the interpreter is created.
+     */
+    
+    if (slavePtr == (Slave *) NULL) {
+        panic("AliasCreationHelper: could not find slave record");
+    }
+
+    if ((targetName == (char *) NULL) || (targetName[0] == '\0')) {
+        if (objc != 0) {
+            Tcl_AppendStringsToObj(Tcl_GetObjResult(curInterp),
+                    "malformed command: should be",
+                    " \"alias ",  aliasName, " {}\"", (char *) NULL);
+            return TCL_ERROR;
+        }
+
+        return DeleteAlias(curInterp, slaveInterp, aliasName);
+    }
+    
+    aliasPtr = (Alias *) ckalloc((unsigned) sizeof(Alias));
+    aliasPtr->aliasName = (char *) ckalloc((unsigned) strlen(aliasName)+1);
+    aliasPtr->targetName = (char *) ckalloc((unsigned) strlen(targetName)+1);
+    strcpy(aliasPtr->aliasName, aliasName);
+    strcpy(aliasPtr->targetName, targetName);
+    aliasPtr->targetInterp = masterInterp;
+
+    aliasPtr->objv = NULL;
+    aliasPtr->objc = objc;
+
+    if (aliasPtr->objc > 0) {
+        aliasPtr->objv =
+            (Tcl_Obj **) ckalloc((unsigned) sizeof(Tcl_Obj *) *
+                    aliasPtr->objc);
+        for (i = 0; i < objc; i++) {
+            aliasPtr->objv[i] = objv[i];
+            Tcl_IncrRefCount(objv[i]);
+        }
+    }
+
+    aliasPtr->slaveCmd = Tcl_CreateObjCommand(slaveInterp, aliasName,
+            AliasCmd, (ClientData) aliasPtr, AliasCmdDeleteProc);
+
+    if (TclPreventAliasLoop(curInterp, slaveInterp, 
+            aliasPtr->slaveCmd) != TCL_OK) {
+
+	/*
+         *  Found an alias loop!  The last call to Tcl_CreateObjCommand
+         *  made the alias point to itself.  Delete the command and
+         *  its alias record.  Be careful to wipe out its client data
+         *  first, so the command doesn't try to delete itself.
+         */
+	
+        Command *cmdPtr = (Command*) aliasPtr->slaveCmd;
+        cmdPtr->clientData = NULL;
+        cmdPtr->deleteProc = NULL;
+        cmdPtr->deleteData = NULL;
+        Tcl_DeleteCommandFromToken(slaveInterp, aliasPtr->slaveCmd);
+
+        for (i = 0; i < objc; i++) {
+            Tcl_DecrRefCount(aliasPtr->objv[i]);
+        }
+        if (aliasPtr->objv != (Tcl_Obj *CONST *) NULL) {
+            ckfree((char *) aliasPtr->objv);
+        }
+        ckfree(aliasPtr->aliasName);
+        ckfree(aliasPtr->targetName);
+        ckfree((char *) aliasPtr);
+
+        /*
+         * The result was already set by TclPreventAliasLoop.
+         */
+
+        return TCL_ERROR;
+    }
+    
+    /*
+     * Make an entry in the alias table. If it already exists delete
+     * the alias command. Then retry.
+     */
+
+    do {
+        hPtr = Tcl_CreateHashEntry(&(slavePtr->aliasTable), aliasName, &new);
+        if (!new) {
+            tmpAliasPtr = (Alias *) Tcl_GetHashValue(hPtr);
+            (void) Tcl_DeleteCommandFromToken(slaveInterp,
+	            tmpAliasPtr->slaveCmd);
+
+            /*
+             * The hash entry should be deleted by the Tcl_DeleteCommand
+             * above, in its command deletion callback (most likely this
+             * will be AliasCmdDeleteProc, which does the deletion).
+             */
+        }
+    } while (new == 0);
+    aliasPtr->aliasEntry = hPtr;
+    Tcl_SetHashValue(hPtr, (ClientData) aliasPtr);
+    
+    /*
+     * Create the new command. We must do it after deleting any old command,
+     * because the alias may be pointing at a renamed alias, as in:
+     *
+     * interp alias {} foo {} bar		# Create an alias "foo"
+     * rename foo zop				# Now rename the alias
+     * interp alias {} foo {} zop		# Now recreate "foo"...
+     */
+
+    targetPtr = (Target *) ckalloc((unsigned) sizeof(Target));
+    targetPtr->slaveCmd = aliasPtr->slaveCmd;
+    targetPtr->slaveInterp = slaveInterp;
+
+    do {
+        hPtr = Tcl_CreateHashEntry(&(masterPtr->targetTable),
+                (char *) aliasCounter, &new);
+	aliasCounter++;
+    } while (new == 0);
+
+    Tcl_SetHashValue(hPtr, (ClientData) targetPtr);
+
+    aliasPtr->targetEntry = hPtr;
+
+    /*
+     * Make sure we clear out the object result when setting the string
+     * result.
+     */
+
+    Tcl_SetObjResult(curInterp, Tcl_NewStringObj(aliasPtr->aliasName, -1));
+    
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * InterpAliasesHelper --
+ *
+ *	Computes a list of aliases defined in an interpreter.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+InterpAliasesHelper(interp, masterPtr, objc, objv)
+    Tcl_Interp *interp;			/* Invoking interpreter. */
+    Master *masterPtr;			/* Master record for current interp. */
+    int objc;				/* How many arguments? */
+    Tcl_Obj *CONST objv[];		/* Actual arguments. */
+{
+    Tcl_Interp *slaveInterp;		/* A slave. */
+    Slave *slavePtr;			/* Record for slave interp. */
+    Tcl_HashEntry *hPtr;		/* Search variable. */
+    Tcl_HashSearch hSearch;		/* Iteration variable. */
+    int len;				/* Dummy length variable. */
+    Tcl_Obj *listObjPtr, *elemObjPtr;	/* Local object pointers. */
+    
+    if ((objc != 2) && (objc != 3)) {
+        Tcl_WrongNumArgs(interp, 2, objv, "?path?");
+        return TCL_ERROR;
+    }
+    if (objc == 3) {
+        slaveInterp = GetInterp(interp, masterPtr,
+                Tcl_GetStringFromObj(objv[2], &len), NULL);
+        if (slaveInterp == (Tcl_Interp *) NULL) {
+            Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                    "interpreter \"", Tcl_GetStringFromObj(objv[2], &len),
+                    "\" not found", (char *) NULL);
+            return TCL_ERROR;
+        }
+    } else {
+        slaveInterp = interp;
+    }
+    slavePtr = (Slave *) Tcl_GetAssocData(slaveInterp,
+            "tclSlaveRecord", NULL);
+    if (slavePtr == (Slave *) NULL) {
+        return TCL_OK;
+    }
+
+    /*
+     * Build a list to return the aliases:
+     */
+            
+    listObjPtr = Tcl_NewListObj(0, (Tcl_Obj **) NULL);
+    for (hPtr = Tcl_FirstHashEntry(&(slavePtr->aliasTable), &hSearch);
+         hPtr != NULL;
+         hPtr = Tcl_NextHashEntry(&hSearch)) {
+
+        elemObjPtr = Tcl_NewStringObj(
+            Tcl_GetHashKey(&(slavePtr->aliasTable), hPtr), -1);
+        Tcl_ListObjAppendElement(interp, listObjPtr, elemObjPtr);
+    }
+    Tcl_SetObjResult(interp, listObjPtr);
+
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * InterpAliasHelper -
+ *
+ *	Handles the different forms of the "interp alias" command:
+ *	- interp alias slavePath aliasName
+ *		Describes an alias.
+ *	- interp alias slavePath aliasName {}
+ *		Deletes an alias.
+ *	- interp alias slavePath srcCmd masterPath targetCmd args...
+ *		Creates an alias.
+ *
+ * Results:
+ *	A Tcl result.
+ *
+ * Side effects:
+ *	See user documentation for details.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+InterpAliasHelper(interp, masterPtr, objc, objv)
+    Tcl_Interp *interp;			/* Current interpreter. */
+    Master *masterPtr;			/* Master record for current interp. */
+    int objc;				/* Number of arguments. */
+    Tcl_Obj *CONST objv[];		/* Argument objects. */
+{
+    Tcl_Interp *slaveInterp,		/* Interpreters used when */
+        *masterInterp;			/* creating an alias btn siblings. */
+    Master *masterMasterPtr;		/* Master record for master interp. */
+    int len;
+
+    if (objc < 4) {
+        Tcl_WrongNumArgs(interp, 2, objv,
+                "slavePath slaveCmd masterPath masterCmd ?args ..?");
+        return TCL_ERROR;
+    }
+    slaveInterp = GetInterp(interp, masterPtr,
+            Tcl_GetStringFromObj(objv[2], &len), NULL);
+    if (slaveInterp == (Tcl_Interp *) NULL) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "could not find interpreter \"",
+                Tcl_GetStringFromObj(objv[2], &len), "\"",
+                (char *) NULL);
+        return TCL_ERROR;
+    }
+    if (objc == 4) {
+        return DescribeAlias(interp, slaveInterp,
+                Tcl_GetStringFromObj(objv[3], &len));
+    }
+    if (objc == 5 && strcmp(Tcl_GetStringFromObj(objv[4], &len), "") == 0) {
+        return DeleteAlias(interp, slaveInterp,
+                Tcl_GetStringFromObj(objv[3], &len));
+    }
+    if (objc < 6) {
+        Tcl_WrongNumArgs(interp, 2, objv,
+                "slavePath slaveCmd masterPath masterCmd ?args ..?");
+        return TCL_ERROR;
+    }
+    masterInterp = GetInterp(interp, masterPtr,
+            Tcl_GetStringFromObj(objv[4], &len), &masterMasterPtr);
+    if (masterInterp == (Tcl_Interp *) NULL) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "could not find interpreter \"",
+                Tcl_GetStringFromObj(objv[4], &len), "\"", (char *) NULL);
+        return TCL_ERROR;
+    }
+    return AliasCreationHelper(interp, slaveInterp, masterInterp,
+            masterMasterPtr, Tcl_GetStringFromObj(objv[3], &len),
+            Tcl_GetStringFromObj(objv[5], &len),
+            objc-6, objv+6);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * InterpExistsHelper --
+ *
+ *	Computes whether a named interpreter exists or not.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+InterpExistsHelper(interp, masterPtr, objc, objv)
+    Tcl_Interp *interp;			/* Current interpreter. */
+    Master *masterPtr;			/* Master record for current interp. */
+    int objc;				/* Number of arguments. */
+    Tcl_Obj *CONST objv[];		/* Argument objects. */
+{
+    Tcl_Obj *objPtr;
+    int len;
+
+    if (objc > 3) {
+        Tcl_WrongNumArgs(interp, 2, objv, "?path?");
+        return TCL_ERROR;
+    }
+    if (objc == 3) {
+        if (GetInterp(interp, masterPtr,
+                Tcl_GetStringFromObj(objv[2], &len), NULL) ==
+                (Tcl_Interp *) NULL) {
+            objPtr = Tcl_NewIntObj(0);
+        } else {
+            objPtr = Tcl_NewIntObj(1);
+        }
+    } else {
+        objPtr = Tcl_NewIntObj(1);
+    }
+    Tcl_SetObjResult(interp, objPtr);
+    
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * InterpEvalHelper --
+ *
+ *	Helper function to handle all the details of evaluating a
+ *	command in another interpreter.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	Whatever the command itself does.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+InterpEvalHelper(interp, masterPtr, objc, objv)
+    Tcl_Interp *interp;			/* Current interpreter. */
+    Master *masterPtr;			/* Master record for current interp. */
+    int objc;				/* Number of arguments. */
+    Tcl_Obj *CONST objv[];		/* Argument objects. */
+{
+    Tcl_Interp *slaveInterp;		/* A slave. */
+    Interp *iPtr;			/* Internal data type for slave. */
+    int len;				/* Dummy length variable. */
+    int result;
+    Tcl_Obj *namePtr, *objPtr;		/* Local object pointer. */
+    char *string;
+
+    if (objc < 4) {
+        Tcl_WrongNumArgs(interp, 2, objv, "path arg ?arg ...?");
+        return TCL_ERROR;
+    }
+    slaveInterp = GetInterp(interp, masterPtr,
+            Tcl_GetStringFromObj(objv[2], &len), NULL);
+    if (slaveInterp == (Tcl_Interp *) NULL) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "interpreter named \"", Tcl_GetStringFromObj(objv[2], &len),
+                "\" not found", (char *) NULL);
+        return TCL_ERROR;
+    }
+    objPtr = Tcl_ConcatObj(objc-3, objv+3);
+    Tcl_IncrRefCount(objPtr);
+    
+    Tcl_Preserve((ClientData) slaveInterp);
+    result = Tcl_EvalObj(slaveInterp, objPtr);
+
+    Tcl_DecrRefCount(objPtr);
+
+    /*
+     * Now make the result and any error information accessible. We
+     * have to be careful because the slave interpreter and the current
+     * interpreter can be the same - do not destroy the result.. This
+     * can happen if an interpreter contains an alias which is directed
+     * at a target command in the same interpreter.
+     */
+
+    if (interp != slaveInterp) {
+        if (result == TCL_ERROR) {
+
+            /*
+             * An error occurred, so transfer error information from
+             * the target interpreter back to our interpreter.
+             */
+
+            iPtr = (Interp *) slaveInterp;
+            if (!(iPtr->flags & ERR_ALREADY_LOGGED)) {
+                Tcl_AddErrorInfo(slaveInterp, "");
+            }
+            iPtr->flags &= (~(ERR_ALREADY_LOGGED));
+            
+            Tcl_ResetResult(interp);
+            namePtr = Tcl_NewStringObj("errorInfo", -1);
+            objPtr = Tcl_ObjGetVar2(slaveInterp, namePtr,
+                    (Tcl_Obj *) NULL, TCL_GLOBAL_ONLY);
+            string = Tcl_GetStringFromObj(objPtr, &len);
+            Tcl_AddObjErrorInfo(interp, string, len);
+            Tcl_SetVar2(interp, "errorCode", (char *) NULL,
+                    Tcl_GetVar2(slaveInterp, "errorCode", (char *)
+                            NULL, TCL_GLOBAL_ONLY),
+                    TCL_GLOBAL_ONLY);
+            Tcl_DecrRefCount(namePtr);
+        }
+
+	/*
+         * Move the result object from one interpreter to the
+         * other.
+         */
+                
+        Tcl_SetObjResult(interp, Tcl_GetObjResult(slaveInterp));
+        Tcl_ResetResult(slaveInterp);
+
+    }
+    Tcl_Release((ClientData) slaveInterp);
+    return result;        
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * InterpExposeHelper --
+ *
+ *	Helper function to handle the details of exposing a command in
+ *	another interpreter.
+ *
+ * Results:
+ *	Standard Tcl result.
+ *
+ * Side effects:
+ *	Exposes a command. From now on the command can be called by scripts
+ *	in the interpreter in which it was exposed.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+InterpExposeHelper(interp, masterPtr, objc, objv)
+    Tcl_Interp *interp;			/* Current interpreter. */
+    Master *masterPtr;			/* Master record for current interp. */
+    int objc;				/* Number of arguments. */
+    Tcl_Obj *CONST objv[];		/* Argument objects. */
+{
+    Tcl_Interp *slaveInterp;		/* A slave. */
+    int len;				/* Dummy length variable. */
+
+    if ((objc != 4) && (objc != 5)) {
+        Tcl_WrongNumArgs(interp, 2, objv,
+                "path hiddenCmdName ?cmdName?");
+        return TCL_ERROR;
+    }
+    if (Tcl_IsSafe(interp)) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "permission denied: safe interpreter cannot expose commands",
+                (char *) NULL);
+        return TCL_ERROR;
+    }
+    slaveInterp = GetInterp(interp, masterPtr,
+            Tcl_GetStringFromObj(objv[2], &len), &masterPtr);
+    if (slaveInterp == (Tcl_Interp *) NULL) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "interpreter \"", Tcl_GetStringFromObj(objv[2], &len),
+                "\" not found", (char *) NULL);
+        return TCL_ERROR;
+    }
+    if (Tcl_ExposeCommand(slaveInterp,
+            Tcl_GetStringFromObj(objv[3], &len),
+                (objc == 5 ?
+                        Tcl_GetStringFromObj(objv[4], &len) :
+                        Tcl_GetStringFromObj(objv[3], &len)))
+            == TCL_ERROR) {
+        if (interp != slaveInterp) {
+            Tcl_SetObjResult(interp, Tcl_GetObjResult(slaveInterp));
+            Tcl_ResetResult(slaveInterp);
+        }
+        return TCL_ERROR;
+    }
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * InterpHideHelper --
+ *
+ *	Helper function that handles the details of hiding a command in
+ *	another interpreter.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	Hides a command. From now on the command cannot be called by
+ *	scripts in that interpreter.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+InterpHideHelper(interp, masterPtr, objc, objv)
+    Tcl_Interp *interp;			/* Current interpreter. */
+    Master *masterPtr;			/* Master record for interp. */
+    int objc;				/* Number of arguments. */
+    Tcl_Obj *CONST objv[];		/* Argument objects. */
+{
+    Tcl_Interp *slaveInterp;		/* A slave. */
+    int len;				/* Dummy length variable. */
+
+    if ((objc != 4) && (objc != 5)) {
+        Tcl_WrongNumArgs(interp, 2, objv,
+                "path cmdName ?hiddenCmdName?");
+        return TCL_ERROR;
+    }
+    if (Tcl_IsSafe(interp)) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "permission denied: safe interpreter cannot hide commands",
+                (char *) NULL);
+        return TCL_ERROR;
+    }
+    slaveInterp = GetInterp(interp, masterPtr,
+            Tcl_GetStringFromObj(objv[2], &len), &masterPtr);
+    if (slaveInterp == (Tcl_Interp *) NULL) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "interpreter \"", Tcl_GetStringFromObj(objv[2], &len),
+                "\" not found", (char *) NULL);
+        return TCL_ERROR;
+    }
+    if (Tcl_HideCommand(slaveInterp, Tcl_GetStringFromObj(objv[3], &len),
+            (objc == 5 ?
+                    Tcl_GetStringFromObj(objv[4], &len) :
+                    Tcl_GetStringFromObj(objv[3], &len)))
+            == TCL_ERROR) {
+        if (interp != slaveInterp) {
+            Tcl_SetObjResult(interp, Tcl_GetObjResult(slaveInterp));
+            Tcl_ResetResult(slaveInterp);
+        }
+        return TCL_ERROR;
+    }
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * InterpHiddenHelper --
+ *
+ *	Computes the list of hidden commands in a named interpreter.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+InterpHiddenHelper(interp, masterPtr, objc, objv)
+    Tcl_Interp *interp;			/* Current interpreter. */
+    Master *masterPtr;			/* Master record for interp. */
+    int objc;				/* Number of arguments. */
+    Tcl_Obj *CONST objv[];		/* Argument objects. */
+{
+    Tcl_Interp *slaveInterp;		/* A slave. */
+    int len;
+    Tcl_HashTable *hTblPtr;		/* Hidden command table. */
+    Tcl_HashEntry *hPtr;		/* Search variable. */
+    Tcl_HashSearch hSearch;		/* Iteration variable. */
+    Tcl_Obj *listObjPtr;		/* Local object pointer. */
+
+    if (objc > 3) {
+        Tcl_WrongNumArgs(interp, 2, objv, "?path?");
+        return TCL_ERROR;
+    }
+    if (objc == 3) {
+        slaveInterp = GetInterp(interp, masterPtr,
+                Tcl_GetStringFromObj(objv[2], &len),
+                &masterPtr);
+        if (slaveInterp == (Tcl_Interp *) NULL) {
+            Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                    "interpreter \"", Tcl_GetStringFromObj(objv[2], &len),
+                    "\" not found", (char *) NULL);
+            return TCL_ERROR;
+        }
+    } else {
+        slaveInterp = interp;
+    }
+            
+    listObjPtr = Tcl_NewListObj(0, (Tcl_Obj **) NULL);
+    hTblPtr = (Tcl_HashTable *) Tcl_GetAssocData(slaveInterp,
+            "tclHiddenCmds", NULL);
+    if (hTblPtr != (Tcl_HashTable *) NULL) {
+        for (hPtr = Tcl_FirstHashEntry(hTblPtr, &hSearch);
+             hPtr != (Tcl_HashEntry *) NULL;
+             hPtr = Tcl_NextHashEntry(&hSearch)) {
+
+            Tcl_ListObjAppendElement(interp, listObjPtr,
+                    Tcl_NewStringObj(Tcl_GetHashKey(hTblPtr, hPtr), -1));
+        }
+    }
+    Tcl_SetObjResult(interp, listObjPtr);
+            
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * InterpInvokeHiddenHelper --
+ *
+ *	Helper routine to handle the details of invoking a hidden
+ *	command in another interpreter.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	Whatever the hidden command does.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+InterpInvokeHiddenHelper(interp, masterPtr, objc, objv)
+    Tcl_Interp *interp;			/* Current interpreter. */
+    Master *masterPtr;			/* Master record for interp. */
+    int objc;				/* Number of arguments. */
+    Tcl_Obj *CONST objv[];		/* Argument objects. */
+{
+    int doGlobal = 0;
+    int len;
+    int result;
+    Tcl_Obj *namePtr, *objPtr;
+    Tcl_Interp *slaveInterp;
+    Interp *iPtr;
+    char *string;
+            
+    if (objc < 4) {
+        Tcl_WrongNumArgs(interp, 2, objv,
+                "path ?-global? cmd ?arg ..?");
+        return TCL_ERROR;
+    }
+    if (Tcl_IsSafe(interp)) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "not allowed to invoke hidden commands from safe interpreter",
+                (char *) NULL);
+        return TCL_ERROR;
+    }
+    if (strcmp(Tcl_GetStringFromObj(objv[3], &len), "-global") == 0) {
+        doGlobal = 1;
+        if (objc < 5) {
+            Tcl_WrongNumArgs(interp, 2, objv,
+                    "path ?-global? cmd ?arg ..?");
+            return TCL_ERROR;
+        }
+    }
+    slaveInterp = GetInterp(interp, masterPtr,
+            Tcl_GetStringFromObj(objv[2], &len), &masterPtr);
+    if (slaveInterp == (Tcl_Interp *) NULL) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "interpreter \"", Tcl_GetStringFromObj(objv[2], &len),
+                "\" not found", (char *) NULL);
+        return TCL_ERROR;
+    }
+    Tcl_Preserve((ClientData) slaveInterp);
+    if (doGlobal) {
+        result = TclObjInvokeGlobal(slaveInterp, objc-4, objv+4,
+                TCL_INVOKE_HIDDEN);
+    } else {
+        result = TclObjInvoke(slaveInterp, objc-3, objv+3, TCL_INVOKE_HIDDEN);
+    }
+
+    /*
+     * Now make the result and any error information accessible. We
+     * have to be careful because the slave interpreter and the current
+     * interpreter can be the same - do not destroy the result.. This
+     * can happen if an interpreter contains an alias which is directed
+     * at a target command in the same interpreter.
+     */
+
+    if (interp != slaveInterp) {
+        if (result == TCL_ERROR) {
+
+            /*
+             * An error occurred, so transfer error information from
+             * the target interpreter back to our interpreter.
+             */
+
+            iPtr = (Interp *) slaveInterp;
+            if (!(iPtr->flags & ERR_ALREADY_LOGGED)) {
+                Tcl_AddErrorInfo(slaveInterp, "");
+            }
+            iPtr->flags &= (~(ERR_ALREADY_LOGGED));
+
+            Tcl_ResetResult(interp);
+            namePtr = Tcl_NewStringObj("errorInfo", -1);
+            objPtr = Tcl_ObjGetVar2(slaveInterp, namePtr,
+                    (Tcl_Obj *) NULL, TCL_GLOBAL_ONLY);
+            Tcl_DecrRefCount(namePtr);
+            string = Tcl_GetStringFromObj(objPtr, &len);
+            Tcl_AddObjErrorInfo(interp, string, len);
+            Tcl_SetVar2(interp, "errorCode", (char *) NULL,
+                    Tcl_GetVar2(slaveInterp, "errorCode", (char *)
+                            NULL, TCL_GLOBAL_ONLY),
+                    TCL_GLOBAL_ONLY);
+        }
+
+	/*
+         * Move the result object from the slave to the master.
+         */
+                
+        Tcl_SetObjResult(interp, Tcl_GetObjResult(slaveInterp));
+        Tcl_ResetResult(slaveInterp);
+    }
+    Tcl_Release((ClientData) slaveInterp);
+    return result;        
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * InterpMarkTrustedHelper --
+ *
+ *	Helper function to handle the details of marking another
+ *	interpreter as trusted (unsafe).
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	Henceforth the hard-wired checks for safety will not prevent
+ *	this interpreter from performing certain operations.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+InterpMarkTrustedHelper(interp, masterPtr, objc, objv)
+    Tcl_Interp *interp;			/* Current interpreter. */
+    Master *masterPtr;			/* Master record for interp. */
+    int objc;				/* Number of arguments. */
+    Tcl_Obj *CONST objv[];		/* Argument objects. */
+{
+    Tcl_Interp *slaveInterp;		/* A slave. */
+    int len;				/* Dummy length variable. */
+
+    if (objc != 3) {
+        Tcl_WrongNumArgs(interp, 2, objv, "path");
+        return TCL_ERROR;
+    }
+    if (Tcl_IsSafe(interp)) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "\"", Tcl_GetStringFromObj(objv[0], &len),
+                " marktrusted\" can only",
+                " be invoked from a trusted interpreter",
+                (char *) NULL);
+        return TCL_ERROR;
+    }
+
+    slaveInterp = GetInterp(interp, masterPtr,
+            Tcl_GetStringFromObj(objv[2], &len), &masterPtr);
+    if (slaveInterp == (Tcl_Interp *) NULL) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "interpreter \"", Tcl_GetStringFromObj(objv[2], &len),
+                "\" not found", (char *) NULL);
+        return TCL_ERROR;
+    }
+    return MarkTrusted(slaveInterp);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * InterpIsSafeHelper --
+ *
+ *	Computes whether a named interpreter is safe.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+InterpIsSafeHelper(interp, masterPtr, objc, objv)
+    Tcl_Interp *interp;			/* Current interpreter. */
+    Master *masterPtr;			/* Master record for interp. */
+    int objc;				/* Number of arguments. */
+    Tcl_Obj *CONST objv[];		/* Argument objects. */
+{
+    Tcl_Interp *slaveInterp;		/* A slave. */
+    int len;				/* Dummy length variable. */
+    Tcl_Obj *objPtr;			/* Local object pointer. */
+
+    if (objc > 3) {
+        Tcl_WrongNumArgs(interp, 2, objv, "?path?");
+        return TCL_ERROR;
+    }
+    if (objc == 3) {
+        slaveInterp = GetInterp(interp, masterPtr,
+                Tcl_GetStringFromObj(objv[2], &len), &masterPtr);
+        if (slaveInterp == (Tcl_Interp *) NULL) {
+            Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                    "interpreter \"",
+                    Tcl_GetStringFromObj(objv[2], &len), "\" not found",
+                    (char *) NULL);
+            return TCL_ERROR;
+        }
+	objPtr = Tcl_NewIntObj(Tcl_IsSafe(slaveInterp));
+    } else {
+	objPtr = Tcl_NewIntObj(Tcl_IsSafe(interp));
+    }
+    Tcl_SetObjResult(interp, objPtr);
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * InterpSlavesHelper --
+ *
+ *	Computes a list of slave interpreters of a named interpreter.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+InterpSlavesHelper(interp, masterPtr, objc, objv)
+    Tcl_Interp *interp;			/* Current interpreter. */
+    Master *masterPtr;			/* Master record for interp. */
+    int objc;				/* Number of arguments. */
+    Tcl_Obj *CONST objv[];		/* Argument objects. */
+{
+    int len;
+    Tcl_HashEntry *hPtr;		/* Search variable. */
+    Tcl_HashSearch hSearch;		/* Iteration variable. */
+    Tcl_Obj *listObjPtr;		/* Local object pointers. */
+
+    if ((objc != 2) && (objc != 3)) {
+        Tcl_WrongNumArgs(interp, 2, objv, "?path?");
+        return TCL_ERROR;
+    }
+    if (objc == 3) {
+        if (GetInterp(interp, masterPtr,
+                Tcl_GetStringFromObj(objv[2], &len), &masterPtr) ==
+                (Tcl_Interp *) NULL) {
+            Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                    "interpreter \"", Tcl_GetStringFromObj(objv[2], &len),
+                    "\" not found", (char *) NULL);
+            return TCL_ERROR;
+        }
+    }
+
+    listObjPtr = Tcl_NewListObj(0, (Tcl_Obj **) NULL);
+    for (hPtr = Tcl_FirstHashEntry(&(masterPtr->slaveTable), &hSearch);
+         hPtr != NULL;
+         hPtr = Tcl_NextHashEntry(&hSearch)) {
+
+        Tcl_ListObjAppendElement(interp, listObjPtr,
+                Tcl_NewStringObj(
+                    Tcl_GetHashKey(&(masterPtr->slaveTable), hPtr), -1));
+    }
+    Tcl_SetObjResult(interp, listObjPtr);
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * InterpShareHelper --
+ *
+ *	Helper function to handle the details of sharing a channel between
+ *	interpreters.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	After this call the named channel will be shared between the
+ *	interpreters named in the arguments.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+InterpShareHelper(interp, masterPtr, objc, objv)
+    Tcl_Interp *interp;			/* Current interpreter. */
+    Master *masterPtr;			/* Master record for interp. */
+    int objc;				/* Number of arguments. */
+    Tcl_Obj *CONST objv[];		/* Argument objects. */
+{
+    Tcl_Interp *slaveInterp;		/* A slave. */
+    Tcl_Interp *masterInterp;		/* Its master. */
+    int len;
+    Tcl_Channel chan;
+
+    if (objc != 5) {
+        Tcl_WrongNumArgs(interp, 2, objv, "srcPath channelId destPath");
+        return TCL_ERROR;
+    }
+    masterInterp = GetInterp(interp, masterPtr,
+            Tcl_GetStringFromObj(objv[2], &len), NULL);
+    if (masterInterp == (Tcl_Interp *) NULL) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "interpreter \"", Tcl_GetStringFromObj(objv[2], &len),
+                "\" not found", (char *) NULL);
+        return TCL_ERROR;
+    }
+    slaveInterp = GetInterp(interp, masterPtr,
+            Tcl_GetStringFromObj(objv[4], &len), NULL);
+    if (slaveInterp == (Tcl_Interp *) NULL) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "interpreter \"", Tcl_GetStringFromObj(objv[4], &len),
+                "\" not found", (char *) NULL);
+        return TCL_ERROR;
+    }
+    chan = Tcl_GetChannel(masterInterp, Tcl_GetStringFromObj(objv[3], &len),
+            NULL);
+    if (chan == (Tcl_Channel) NULL) {
+        if (interp != masterInterp) {
+            Tcl_SetObjResult(interp, Tcl_GetObjResult(masterInterp));
+            Tcl_ResetResult(masterInterp);
+        }
+        return TCL_ERROR;
+    }
+    Tcl_RegisterChannel(slaveInterp, chan);
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * InterpTargetHelper --
+ *
+ *	Helper function to compute the target of an alias.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+InterpTargetHelper(interp, masterPtr, objc, objv)
+    Tcl_Interp *interp;			/* Current interpreter. */
+    Master *masterPtr;			/* Master record for interp. */
+    int objc;				/* Number of arguments. */
+    Tcl_Obj *CONST objv[];		/* Argument objects. */
+{
+    int len;
+    
+    if (objc != 4) {
+        Tcl_WrongNumArgs(interp, 2, objv, "path alias");
+        return TCL_ERROR;
+    }
+    return GetTarget(interp,
+            Tcl_GetStringFromObj(objv[2], &len),
+            Tcl_GetStringFromObj(objv[3], &len));
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * InterpTransferHelper --
+ *
+ *	Helper function to handle the details of transferring ownership
+ *	of a channel between interpreters.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	After the call, the named channel will be registered in the target
+ *	interpreter and no longer available for use in the source interpreter.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+InterpTransferHelper(interp, masterPtr, objc, objv)
+    Tcl_Interp *interp;			/* Current interpreter. */
+    Master *masterPtr;			/* Master record for interp. */
+    int objc;				/* Number of arguments. */
+    Tcl_Obj *CONST objv[];		/* Argument objects. */
+{
+    Tcl_Interp *slaveInterp;		/* A slave. */
+    Tcl_Interp *masterInterp;		/* Its master. */
+    int len;
+    Tcl_Channel chan;
+            
+    if (objc != 5) {
+        Tcl_WrongNumArgs(interp, 2, objv,
+                "srcPath channelId destPath");
+        return TCL_ERROR;
+    }
+    masterInterp = GetInterp(interp, masterPtr,
+            Tcl_GetStringFromObj(objv[2], &len), NULL);
+    if (masterInterp == (Tcl_Interp *) NULL) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "interpreter \"", Tcl_GetStringFromObj(objv[2], &len),
+                "\" not found", (char *) NULL);
+        return TCL_ERROR;
+    }
+    slaveInterp = GetInterp(interp, masterPtr,
+            Tcl_GetStringFromObj(objv[4], &len), NULL);
+    if (slaveInterp == (Tcl_Interp *) NULL) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "interpreter \"", Tcl_GetStringFromObj(objv[4], &len),
+                "\" not found", (char *) NULL);
+        return TCL_ERROR;
+    }
+    chan = Tcl_GetChannel(masterInterp,
+            Tcl_GetStringFromObj(objv[3], &len), NULL);
+    if (chan == (Tcl_Channel) NULL) {
+        if (interp != masterInterp) {
+
+            /*
+             * After fixing objresult, this code will change to:
+             * Tcl_SetObjResult(interp, Tcl_GetObjResult(masterInterp));
+             */
+            
+            Tcl_SetObjResult(interp, Tcl_GetObjResult(masterInterp));
+            Tcl_ResetResult(masterInterp);
+        }
+        return TCL_ERROR;
+    }
+    Tcl_RegisterChannel(slaveInterp, chan);
+    if (Tcl_UnregisterChannel(masterInterp, chan) != TCL_OK) {
+        if (interp != masterInterp) {
+            Tcl_SetObjResult(interp, Tcl_GetObjResult(masterInterp));
+            Tcl_ResetResult(masterInterp);
+        }
+        return TCL_ERROR;
+    }
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * DescribeAlias --
+ *
+ *	Sets the interpreter's result object to a Tcl list describing
+ *	the given alias in the given interpreter: its target command
+ *	and the additional arguments to prepend to any invocation
+ *	of the alias.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+DescribeAlias(interp, slaveInterp, aliasName)
+    Tcl_Interp *interp;			/* Interpreter for result & errors. */
+    Tcl_Interp *slaveInterp;		/* Interpreter defining alias. */
+    char *aliasName;			/* Name of alias to describe. */
+{
+    Slave *slavePtr;			/* Slave interp slave record. */
+    Tcl_HashEntry *hPtr;		/* Search variable. */
+    Alias *aliasPtr;			/* Structure describing alias. */
+    int i;				/* Loop variable. */
+    Tcl_Obj *listObjPtr;		/* Local object pointer. */
+
+    slavePtr = (Slave *) Tcl_GetAssocData(slaveInterp, "tclSlaveRecord",
+            NULL);
+
+    /*
+     * The slave record should always be present because it is created
+     * by Tcl_CreateInterp.
+     */
+    
+    if (slavePtr == (Slave *) NULL) {
+        panic("DescribeAlias: could not find slave record");
+    }
+    hPtr = Tcl_FindHashEntry(&(slavePtr->aliasTable), aliasName);
+    if (hPtr == (Tcl_HashEntry *) NULL) {
+        return TCL_OK;
+    }
+    aliasPtr = (Alias *) Tcl_GetHashValue(hPtr);
+
+    listObjPtr = Tcl_NewListObj(0, (Tcl_Obj **) NULL);
+    Tcl_ListObjAppendElement(interp, listObjPtr,
+            Tcl_NewStringObj(aliasPtr->targetName, -1));
+    for (i = 0; i < aliasPtr->objc; i++) {
+        Tcl_ListObjAppendElement(interp, listObjPtr, aliasPtr->objv[i]);
+    }
+    Tcl_SetObjResult(interp, listObjPtr);
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * DeleteAlias --
+ *
+ *	Deletes the given alias from the slave interpreter given.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	Deletes the alias from the slave interpreter.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+DeleteAlias(interp, slaveInterp, aliasName)
+    Tcl_Interp *interp;		/* Interpreter for result and errors. */
+    Tcl_Interp *slaveInterp;	/* Interpreter defining alias. */
+    char *aliasName;		/* Name of alias to delete. */
+{
+    Slave *slavePtr;		/* Slave record for slave interpreter. */
+    Alias *aliasPtr;		/* Points at alias structure to delete. */
+    Tcl_HashEntry *hPtr;	/* Search variable. */
+    char *tmpPtr, *namePtr;	/* Local pointers to name of command to
+                                 * be deleted. */
+
+    slavePtr = (Slave *) Tcl_GetAssocData(slaveInterp, "tclSlaveRecord",
+            NULL);
+    if (slavePtr == (Slave *) NULL) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "alias \"", aliasName, "\" not found", (char *) NULL);
+        return TCL_ERROR;
+    }
+    
+    /*
+     * Get the alias from the alias table, then delete the command. The
+     * deleteProc on the alias command will take care of removing the entry
+     * from the alias table.
+     */
+
+    hPtr = Tcl_FindHashEntry(&(slavePtr->aliasTable), aliasName);
+    if (hPtr == (Tcl_HashEntry *) NULL) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "alias \"", aliasName, "\" not found", (char *) NULL);
+        return TCL_ERROR;
+    }
+    aliasPtr = (Alias *) Tcl_GetHashValue(hPtr);
+
+    /*
+     * Get a copy of the real name of the command -- it might have
+     * been renamed, and we want to delete the renamed command, not
+     * the current command (if any) by the name of the original alias.
+     * We need the local copy because the name may get smashed when the
+     * command to delete is exposed, if it was hidden.
+     */
+
+    tmpPtr = Tcl_GetCommandName(slaveInterp, aliasPtr->slaveCmd);
+    namePtr = (char *) ckalloc((unsigned) strlen(tmpPtr) + 1);
+    strcpy(namePtr, tmpPtr);
+
+    /*
+     * NOTE: The deleteProc for this command will delete the
+     * alias from the hash table. The deleteProc will also
+     * delete the target information from the master interpreter
+     * target table.
+     */
+
+    if (Tcl_DeleteCommand(slaveInterp, namePtr) != 0) {
+        if (Tcl_ExposeCommand(slaveInterp, namePtr, namePtr) != TCL_OK) {
+            panic("DeleteAlias: did not find alias to be deleted");
+        }
+        if (Tcl_DeleteCommand(slaveInterp, namePtr) != 0) {
+            panic("DeleteAlias: did not find alias to be deleted");
+        }
+    }
+    ckfree(namePtr);
+
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_GetInterpPath --
+ *
+ *	Sets the result of the asking interpreter to a proper Tcl list
+ *	containing the names of interpreters between the asking and
+ *	target interpreters. The target interpreter must be either the
+ *	same as the asking interpreter or one of its slaves (including
+ *	recursively).
+ *
+ * Results:
+ *	TCL_OK if the target interpreter is the same as, or a descendant
+ *	of, the asking interpreter; TCL_ERROR else. This way one can
+ *	distinguish between the case where the asking and target interps
+ *	are the same (an empty list is the result, and TCL_OK is returned)
+ *	and when the target is not a descendant of the asking interpreter
+ *	(in which case the Tcl result is an error message and the function
+ *	returns TCL_ERROR).
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_GetInterpPath(askingInterp, targetInterp)
+    Tcl_Interp *askingInterp;	/* Interpreter to start search from. */
+    Tcl_Interp *targetInterp;	/* Interpreter to find. */
+{
+    Master *masterPtr;		/* Interim storage for Master record. */
+    Slave *slavePtr;		/* Interim storage for Slave record. */
+    
+    if (targetInterp == askingInterp) {
+        return TCL_OK;
+    }
+    if (targetInterp == (Tcl_Interp *) NULL) {
+        return TCL_ERROR;
+    }
+    slavePtr = (Slave *) Tcl_GetAssocData(targetInterp, "tclSlaveRecord",
+            NULL);
+    if (slavePtr == (Slave *) NULL) {
+        return TCL_ERROR;
+    }
+    if (Tcl_GetInterpPath(askingInterp, slavePtr->masterInterp) == TCL_ERROR) {
+
+        /*
+         * The result of askingInterp was set by recursive call.
+         */
+
+        return TCL_ERROR;
+    }
+    masterPtr = (Master *) Tcl_GetAssocData(slavePtr->masterInterp,
+            "tclMasterRecord", NULL);
+    if (masterPtr == (Master *) NULL) {
+        panic("Tcl_GetInterpPath: could not find master record");
+    }
+    Tcl_AppendElement(askingInterp, Tcl_GetHashKey(&(masterPtr->slaveTable),
+            slavePtr->slaveEntry));
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * GetTarget --
+ *
+ *	Sets the result of the invoking interpreter to a path name for
+ *	the target interpreter of an alias in one of the slaves.
+ *
+ * Results:
+ *	TCL_OK if the target interpreter of the alias is a slave of the
+ *	invoking interpreter, TCL_ERROR else.
+ *
+ * Side effects:
+ *	Sets the result of the invoking interpreter.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+GetTarget(askingInterp, path, aliasName)
+    Tcl_Interp *askingInterp;	/* Interpreter to start search from. */
+    char *path;			/* The path of the interp to find. */
+    char *aliasName;		/* The target of this allias. */
+{
+    Tcl_Interp *slaveInterp;	/* Interim storage for slave. */
+    Slave *slaveSlavePtr;	/* Its Slave record. */
+    Master *masterPtr;		/* Interim storage for Master record. */
+    Tcl_HashEntry *hPtr;	/* Search element. */
+    Alias *aliasPtr;		/* Data describing the alias. */
+
+    Tcl_ResetResult(askingInterp);
+    masterPtr = (Master *) Tcl_GetAssocData(askingInterp, "tclMasterRecord",
+            NULL);
+    if (masterPtr == (Master *) NULL) {
+        panic("GetTarget: could not find master record");
+    }
+    slaveInterp = GetInterp(askingInterp, masterPtr, path, NULL);
+    if (slaveInterp == (Tcl_Interp *) NULL) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(askingInterp),
+                "could not find interpreter \"", path, "\"", (char *) NULL);
+        return TCL_ERROR;
+    }
+    slaveSlavePtr = (Slave *) Tcl_GetAssocData(slaveInterp, "tclSlaveRecord",
+            NULL);
+    if (slaveSlavePtr == (Slave *) NULL) {
+        panic("GetTarget: could not find slave record");
+    }
+    hPtr = Tcl_FindHashEntry(&(slaveSlavePtr->aliasTable), aliasName);
+    if (hPtr == (Tcl_HashEntry *) NULL) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(askingInterp),
+                "alias \"", aliasName, "\" in path \"", path, "\" not found",
+                (char *) NULL);
+        return TCL_ERROR;
+    }
+    aliasPtr = (Alias *) Tcl_GetHashValue(hPtr);
+    if (aliasPtr == (Alias *) NULL) {
+        panic("GetTarget: could not find alias record");
+    }
+    
+    if (Tcl_GetInterpPath(askingInterp, aliasPtr->targetInterp) == TCL_ERROR) {
+        Tcl_ResetResult(askingInterp);
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(askingInterp),
+                "target interpreter for alias \"",
+                aliasName, "\" in path \"", path, "\" is not my descendant",
+                (char *) NULL);
+        return TCL_ERROR;
+    }
+    
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_InterpCmd --
+ *
+ *	This procedure is invoked to process the "interp" Tcl command.
+ *	See the user documentation for details on what it does.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	See the user documentation.
+ *
+ *----------------------------------------------------------------------
+ */
+	/* ARGSUSED */
+int
+Tcl_InterpObjCmd(clientData, interp, objc, objv)
+    ClientData clientData;		/* Unused. */
+    Tcl_Interp *interp;			/* Current interpreter. */
+    int objc;				/* Number of arguments. */
+    Tcl_Obj *CONST objv[];		/* Argument objects. */
+{
+    Master *masterPtr;			/* Master record for current interp. */
+    int result;				/* Local result variable. */
+
+    /*
+     * These are all the different subcommands for this command:
+     */
+    
+    static char *subCmds[] = {
+        "alias", "aliases", "create", "delete", "eval", "exists",
+	"expose", "hide", "hidden", "issafe", "invokehidden",
+        "marktrusted", "slaves", "share", "target", "transfer",
+        (char *) NULL};
+    enum ISubCmdIdx {
+        IAliasIdx, IAliasesIdx, ICreateIdx, IDeleteIdx, IEvalIdx,
+	IExistsIdx, IExposeIdx, IHideIdx, IHiddenIdx, IIsSafeIdx,
+	IInvokeHiddenIdx, IMarkTrustedIdx, ISlavesIdx, IShareIdx,
+        ITargetIdx, ITransferIdx
+    } index;
+
+    if (objc < 2) {
+        Tcl_WrongNumArgs(interp, 1, objv, "cmd ?arg ...?");
+        return TCL_ERROR;
+    }
+
+    masterPtr = (Master *) Tcl_GetAssocData(interp, "tclMasterRecord", NULL);
+    if (masterPtr == (Master *) NULL) {
+        panic("Tcl_InterpCmd: could not find master record");
+    }
+
+    result = Tcl_GetIndexFromObj(interp, objv[1], subCmds, "option",
+            0, (int *) &index);
+    if (result != TCL_OK) {
+        return result;
+    }
+    
+    switch (index) {
+        case IAliasIdx:
+            return InterpAliasHelper(interp, masterPtr, objc, objv);
+        case IAliasesIdx:
+            return InterpAliasesHelper(interp, masterPtr, objc, objv);
+        case ICreateIdx:
+            return CreateInterpObject(interp, masterPtr, objc, objv);
+        case IDeleteIdx:
+            return DeleteInterpObject(interp, masterPtr, objc, objv);
+        case IEvalIdx:
+            return InterpEvalHelper(interp, masterPtr, objc, objv);
+        case IExistsIdx:
+            return InterpExistsHelper(interp, masterPtr, objc, objv);
+        case IExposeIdx:
+            return InterpExposeHelper(interp, masterPtr, objc, objv);
+        case IHideIdx:
+            return InterpHideHelper(interp, masterPtr, objc, objv);
+        case IHiddenIdx:
+            return InterpHiddenHelper(interp, masterPtr, objc, objv);
+        case IIsSafeIdx:
+            return InterpIsSafeHelper(interp, masterPtr, objc, objv);
+        case IInvokeHiddenIdx:
+            return InterpInvokeHiddenHelper(interp, masterPtr, objc, objv);
+        case IMarkTrustedIdx:
+            return InterpMarkTrustedHelper(interp, masterPtr, objc, objv);
+        case ISlavesIdx:
+            return InterpSlavesHelper(interp, masterPtr, objc, objv);
+        case IShareIdx:
+            return InterpShareHelper(interp, masterPtr, objc, objv);
+        case ITargetIdx:
+            return InterpTargetHelper(interp, masterPtr, objc, objv);
+        case ITransferIdx:
+            return InterpTransferHelper(interp, masterPtr, objc, objv);
+    }
+
+    return TCL_ERROR;    
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * SlaveAliasHelper --
+ *
+ *	Helper function to construct or query an alias for a slave
+ *	interpreter.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	Potentially creates a new alias.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+SlaveAliasHelper(interp, slaveInterp, slavePtr, objc, objv)
+    Tcl_Interp	*interp;		/* Current interpreter. */
+    Tcl_Interp	*slaveInterp;		/* The slave interpreter. */
+    Slave *slavePtr;			/* Its slave record. */
+    int objc;				/* Count of arguments. */
+    Tcl_Obj *CONST objv[];		/* Vector of arguments. */
+{
+    Master *masterPtr;
+    int len;
+
+    switch (objc-2) {
+        case 0:
+            Tcl_WrongNumArgs(interp, 2, objv,
+                    "aliasName ?targetName? ?args..?");
+            return TCL_ERROR;
+
+        case 1:
+
+            /*
+             * Return the name of the command in the current
+             * interpreter for which the argument is an alias in the
+             * slave interpreter, and the list of saved arguments
+             */
+
+            return DescribeAlias(interp, slaveInterp,
+                    Tcl_GetStringFromObj(objv[2], &len));
+
+        default:
+            masterPtr = (Master *) Tcl_GetAssocData(interp,
+                    "tclMasterRecord", NULL);
+            if (masterPtr == (Master *) NULL) {
+                panic("SlaveObjectCmd: could not find master record");
+            }
+            return AliasCreationHelper(interp, slaveInterp, interp,
+                    masterPtr,
+                    Tcl_GetStringFromObj(objv[2], &len),
+                    Tcl_GetStringFromObj(objv[3], &len),
+                    objc-4, objv+4);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * SlaveAliasesHelper --
+ *
+ *	Computes a list of aliases defined in a slave interpreter.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+SlaveAliasesHelper(interp, slaveInterp, slavePtr, objc, objv)
+    Tcl_Interp	*interp;		/* Current interpreter. */
+    Tcl_Interp	*slaveInterp;		/* The slave interpreter. */
+    Slave *slavePtr;			/* Its slave record. */
+    int objc;				/* Count of arguments. */
+    Tcl_Obj *CONST objv[];		/* Vector of arguments. */
+{
+    Tcl_HashEntry *hPtr;		/* For local searches. */
+    Tcl_HashSearch hSearch;		/* For local searches. */
+    Tcl_Obj *listObjPtr;		/* Local object pointer. */
+    Alias *aliasPtr;			/* Alias information. */
+
+    /*
+     * Return the names of all the aliases created in the
+     * slave interpreter.
+     */
+
+    listObjPtr = Tcl_NewListObj(0, (Tcl_Obj **) NULL);
+    for (hPtr = Tcl_FirstHashEntry(&(slavePtr->aliasTable),
+            &hSearch);
+         hPtr != (Tcl_HashEntry *) NULL;
+         hPtr = Tcl_NextHashEntry(&hSearch)) {
+        aliasPtr = (Alias *) Tcl_GetHashValue(hPtr);
+        Tcl_ListObjAppendElement(interp, listObjPtr,
+                Tcl_NewStringObj(aliasPtr->aliasName, -1));
+    }
+    Tcl_SetObjResult(interp, listObjPtr);
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * SlaveEvalHelper --
+ *
+ *	Helper function to evaluate a command in a slave interpreter.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	Whatever the command does.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+SlaveEvalHelper(interp, slaveInterp, slavePtr, objc, objv)
+    Tcl_Interp	*interp;		/* Current interpreter. */
+    Tcl_Interp	*slaveInterp;		/* The slave interpreter. */
+    Slave *slavePtr;			/* Its slave record. */
+    int objc;				/* Count of arguments. */
+    Tcl_Obj *CONST objv[];		/* Vector of arguments. */
+{
+    Interp *iPtr;			/* Internal data type for slave. */
+    Tcl_Obj *objPtr;			/* Local object pointer. */
+    Tcl_Obj *namePtr;			/* Local object pointer. */
+    int len;
+    char *string;
+    int result;
+    
+    if (objc < 3) {
+        Tcl_WrongNumArgs(interp, 2, objv, "arg ?arg ...?");
+        return TCL_ERROR;
+    }
+
+    objPtr = Tcl_ConcatObj(objc-2, objv+2);
+    Tcl_IncrRefCount(objPtr);
+    
+    Tcl_Preserve((ClientData) slaveInterp);
+    result = Tcl_EvalObj(slaveInterp, objPtr);
+
+    Tcl_DecrRefCount(objPtr);
+
+    /*
+     * Make the result and any error information accessible. We have
+     * to be careful because the slave interpreter and the current
+     * interpreter can be the same - do not destroy the result.. This
+     * can happen if an interpreter contains an alias which is directed
+     * at a target command in the same interpreter.
+     */
+
+    if (interp != slaveInterp) {
+        if (result == TCL_ERROR) {
+
+            /*
+             * An error occurred, so transfer error information from the
+             * destination interpreter back to our interpreter. 
+             */
+
+            iPtr = (Interp *) slaveInterp;
+            if (!(iPtr->flags & ERR_ALREADY_LOGGED)) {
+                Tcl_AddErrorInfo(slaveInterp, "");
+            }
+            iPtr->flags &= (~(ERR_ALREADY_LOGGED));
+
+            Tcl_ResetResult(interp);
+            namePtr = Tcl_NewStringObj("errorInfo", -1);
+            objPtr = Tcl_ObjGetVar2(slaveInterp, namePtr,
+                    (Tcl_Obj *) NULL, TCL_GLOBAL_ONLY);
+            string = Tcl_GetStringFromObj(objPtr, &len);
+            Tcl_AddObjErrorInfo(interp, string, len);
+            Tcl_SetVar2(interp, "errorCode", (char *) NULL,
+                    Tcl_GetVar2(slaveInterp, "errorCode", (char *)
+                            NULL, TCL_GLOBAL_ONLY),
+                    TCL_GLOBAL_ONLY);
+            Tcl_DecrRefCount(namePtr);
+        }
+
+	/*
+         * Move the result object from one interpreter to the
+         * other.
+         */
+                
+        Tcl_SetObjResult(interp, Tcl_GetObjResult(slaveInterp));
+        Tcl_ResetResult(slaveInterp);
+    }
+    Tcl_Release((ClientData) slaveInterp);
+    return result;        
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * SlaveExposeHelper --
+ *
+ *	Helper function to expose a command in a slave interpreter.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	After this call scripts in the slave will be able to invoke
+ *	the newly exposed command.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+SlaveExposeHelper(interp, slaveInterp, slavePtr, objc, objv)
+    Tcl_Interp	*interp;		/* Current interpreter. */
+    Tcl_Interp	*slaveInterp;		/* The slave interpreter. */
+    Slave *slavePtr;			/* Its slave record. */
+    int objc;				/* Count of arguments. */
+    Tcl_Obj *CONST objv[];		/* Vector of arguments. */
+{
+    int len;
+    
+    if ((objc != 3) && (objc != 4)) {
+        Tcl_WrongNumArgs(interp, 2, objv, "hiddenCmdName ?cmdName?");
+        return TCL_ERROR;
+    }
+    if (Tcl_IsSafe(interp)) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "permission denied: safe interpreter cannot expose commands",
+                (char *) NULL);
+        return TCL_ERROR;
+    }
+    if (Tcl_ExposeCommand(slaveInterp, Tcl_GetStringFromObj(objv[2], &len),
+            (objc == 4 ?
+                    Tcl_GetStringFromObj(objv[3], &len) :
+                    Tcl_GetStringFromObj(objv[2], &len)))
+            == TCL_ERROR) {
+        Tcl_SetObjResult(interp, Tcl_GetObjResult(slaveInterp));
+        Tcl_ResetResult(slaveInterp);
+        return TCL_ERROR;
+    }
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * SlaveHideHelper --
+ *
+ *	Helper function to hide a command in a slave interpreter.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	After this call scripts in the slave will no longer be able
+ *	to invoke the named command.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+SlaveHideHelper(interp, slaveInterp, slavePtr, objc, objv)
+    Tcl_Interp	*interp;		/* Current interpreter. */
+    Tcl_Interp	*slaveInterp;		/* The slave interpreter. */
+    Slave *slavePtr;			/* Its slave record. */
+    int objc;				/* Count of arguments. */
+    Tcl_Obj *CONST objv[];		/* Vector of arguments. */
+{
+    int len;
+
+    if ((objc != 3) && (objc != 4)) {
+        Tcl_WrongNumArgs(interp, 2, objv, "cmdName ?hiddenCmdName?");
+        return TCL_ERROR;
+    }
+    if (Tcl_IsSafe(interp)) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "permission denied: safe interpreter cannot hide commands",
+                (char *) NULL);
+        return TCL_ERROR;
+    }
+    if (Tcl_HideCommand(slaveInterp, Tcl_GetStringFromObj(objv[2], &len),
+            (objc == 4 ?
+                    Tcl_GetStringFromObj(objv[3], &len) :
+                    Tcl_GetStringFromObj(objv[2], &len)))
+            == TCL_ERROR) {
+        Tcl_SetObjResult(interp, Tcl_GetObjResult(slaveInterp));
+        Tcl_ResetResult(slaveInterp);
+        return TCL_ERROR;
+    }
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * SlaveHiddenHelper --
+ *
+ *	Helper function to compute list of hidden commands in a slave
+ *	interpreter.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+SlaveHiddenHelper(interp, slaveInterp, slavePtr, objc, objv)
+    Tcl_Interp	*interp;		/* Current interpreter. */
+    Tcl_Interp	*slaveInterp;		/* The slave interpreter. */
+    Slave *slavePtr;			/* Its slave record. */
+    int objc;				/* Count of arguments. */
+    Tcl_Obj *CONST objv[];		/* Vector of arguments. */
+{
+    Tcl_Obj *listObjPtr;		/* Local object pointer. */
+    Tcl_HashTable *hTblPtr;		/* For local searches. */
+    Tcl_HashEntry *hPtr;		/* For local searches. */
+    Tcl_HashSearch hSearch;		/* For local searches. */
+    
+    if (objc != 2) {
+        Tcl_WrongNumArgs(interp, 2, objv, NULL);
+        return TCL_ERROR;
+    }
+
+    listObjPtr = Tcl_NewListObj(0, (Tcl_Obj **) NULL);
+    hTblPtr = (Tcl_HashTable *) Tcl_GetAssocData(slaveInterp,
+            "tclHiddenCmds", NULL);
+    if (hTblPtr != (Tcl_HashTable *) NULL) {
+        for (hPtr = Tcl_FirstHashEntry(hTblPtr, &hSearch);
+             hPtr != (Tcl_HashEntry *) NULL;
+             hPtr = Tcl_NextHashEntry(&hSearch)) {
+            Tcl_ListObjAppendElement(interp, listObjPtr,
+                    Tcl_NewStringObj(Tcl_GetHashKey(hTblPtr, hPtr), -1));
+        }
+    }
+    Tcl_SetObjResult(interp, listObjPtr);
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * SlaveIsSafeHelper --
+ *
+ *	Helper function to compute whether a slave interpreter is safe.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+SlaveIsSafeHelper(interp, slaveInterp, slavePtr, objc, objv)
+    Tcl_Interp	*interp;		/* Current interpreter. */
+    Tcl_Interp	*slaveInterp;		/* The slave interpreter. */
+    Slave *slavePtr;			/* Its slave record. */
+    int objc;				/* Count of arguments. */
+    Tcl_Obj *CONST objv[];		/* Vector of arguments. */
+{
+    Tcl_Obj *resultPtr;			/* Local object pointer. */
+
+    if (objc > 2) {
+        Tcl_WrongNumArgs(interp, 2, objv, NULL);
+        return TCL_ERROR;
+    }
+    resultPtr = Tcl_NewIntObj(Tcl_IsSafe(slaveInterp));
+
+    Tcl_SetObjResult(interp, resultPtr);
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * SlaveInvokeHiddenHelper --
+ *
+ *	Helper function to invoke a hidden command in a slave interpreter.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	Whatever the hidden command does.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+SlaveInvokeHiddenHelper(interp, slaveInterp, slavePtr, objc, objv)
+    Tcl_Interp	*interp;		/* Current interpreter. */
+    Tcl_Interp	*slaveInterp;		/* The slave interpreter. */
+    Slave *slavePtr;			/* Its slave record. */
+    int objc;				/* Count of arguments. */
+    Tcl_Obj *CONST objv[];		/* Vector of arguments. */
+{
+    Interp *iPtr;
+    Master *masterPtr;
+    int doGlobal = 0;
+    int result;
+    int len;
+    char *string;
+    Tcl_Obj *namePtr, *objPtr;
+            
+    if (objc < 3) {
+        Tcl_WrongNumArgs(interp, 2, objv,
+                "?-global? cmd ?arg ..?");
+        return TCL_ERROR;
+    }
+    if (Tcl_IsSafe(interp)) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "not allowed to invoke hidden commands from safe interpreter",
+                (char *) NULL);
+        return TCL_ERROR;
+    }
+    if (strcmp(Tcl_GetStringFromObj(objv[2], &len), "-global") == 0) {
+        doGlobal = 1;
+        if (objc < 4) {
+            Tcl_WrongNumArgs(interp, 2, objv,
+                    "path ?-global? cmd ?arg ..?");
+            return TCL_ERROR;
+        }
+    }
+    masterPtr = (Master *) Tcl_GetAssocData(slaveInterp,
+            "tclMasterRecord", NULL);
+    if (masterPtr == (Master *) NULL) {
+        panic("SlaveObjectCmd: could not find master record");
+    }
+    Tcl_Preserve((ClientData) slaveInterp);
+    if (doGlobal) {
+        result = TclObjInvokeGlobal(slaveInterp, objc-3, objv+3,
+                TCL_INVOKE_HIDDEN);
+    } else {
+        result = TclObjInvoke(slaveInterp, objc-2, objv+2,
+                TCL_INVOKE_HIDDEN);
+    }
+
+    /*
+     * Now make the result and any error information accessible. We
+     * have to be careful because the slave interpreter and the current
+     * interpreter can be the same - do not destroy the result.. This
+     * can happen if an interpreter contains an alias which is directed
+     * at a target command in the same interpreter.
+     */
+
+    if (interp != slaveInterp) {
+        if (result == TCL_ERROR) {
+
+            /*
+             * An error occurred, so transfer error information from
+             * the target interpreter back to our interpreter.
+             */
+
+            iPtr = (Interp *) slaveInterp;
+            if (!(iPtr->flags & ERR_ALREADY_LOGGED)) {
+                Tcl_AddErrorInfo(slaveInterp, "");
+            }
+            iPtr->flags &= (~(ERR_ALREADY_LOGGED));
+
+            Tcl_ResetResult(interp);
+            namePtr = Tcl_NewStringObj("errorInfo", -1);
+            objPtr = Tcl_ObjGetVar2(slaveInterp, namePtr,
+                    (Tcl_Obj *) NULL, TCL_GLOBAL_ONLY);
+            string = Tcl_GetStringFromObj(objPtr, &len);
+            Tcl_AddObjErrorInfo(interp, string, len);
+            Tcl_SetVar2(interp, "errorCode", (char *) NULL,
+                    Tcl_GetVar2(slaveInterp, "errorCode", (char *)
+                            NULL, TCL_GLOBAL_ONLY),
+                    TCL_GLOBAL_ONLY);
+            Tcl_DecrRefCount(namePtr);
+        }
+
+	/*
+         * Move the result object from the slave to the master.
+         */
+                
+        Tcl_SetObjResult(interp, Tcl_GetObjResult(slaveInterp));
+        Tcl_ResetResult(slaveInterp);
+    }
+    Tcl_Release((ClientData) slaveInterp);
+    return result;        
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * SlaveMarkTrustedHelper --
+ *
+ *	Helper function to mark a slave interpreter as trusted (unsafe).
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	After this call the hard-wired security checks in the core no
+ *	longer prevent the slave from performing certain operations.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+SlaveMarkTrustedHelper(interp, slaveInterp, slavePtr, objc, objv)
+    Tcl_Interp	*interp;		/* Current interpreter. */
+    Tcl_Interp	*slaveInterp;		/* The slave interpreter. */
+    Slave *slavePtr;			/* Its slave record. */
+    int objc;				/* Count of arguments. */
+    Tcl_Obj *CONST objv[];		/* Vector of arguments. */
+{
+    int len;
+    
+    if (objc != 2) {
+        Tcl_WrongNumArgs(interp, 2, objv, NULL);
+        return TCL_ERROR;
+    }
+    if (Tcl_IsSafe(interp)) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "\"", Tcl_GetStringFromObj(objv[0], &len), " marktrusted\"",
+                " can only be invoked from a trusted interpreter",
+                (char *) NULL);
+        return TCL_ERROR;
+    }
+    return MarkTrusted(slaveInterp);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * SlaveObjectCmd --
+ *
+ *	Command to manipulate an interpreter, e.g. to send commands to it
+ *	to be evaluated. One such command exists for each slave interpreter.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	See user documentation for details.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+SlaveObjectCmd(clientData, interp, objc, objv)
+    ClientData clientData;		/* Slave interpreter. */
+    Tcl_Interp *interp;			/* Current interpreter. */
+    int objc;				/* Number of arguments. */
+    Tcl_Obj *CONST objv[];		/* The argument vector. */
+{
+    Slave *slavePtr;			/* Slave record. */
+    Tcl_Interp *slaveInterp;		/* Slave interpreter. */
+    int result;				/* Loop counter, status return. */
+    int len;				/* Length of command name. */
+
+    /*
+     * These are all the different subcommands for this command:
+     */
+    
+    static char *subCmds[] = {
+        "alias", "aliases",
+        "eval", "expose",
+        "hide", "hidden",
+        "issafe", "invokehidden",
+        "marktrusted",
+        (char *) NULL};
+    enum ISubCmdIdx {
+        IAliasIdx, IAliasesIdx,
+        IEvalIdx, IExposeIdx,
+        IHideIdx, IHiddenIdx,
+        IIsSafeIdx, IInvokeHiddenIdx,
+        IMarkTrustedIdx
+    } index;
+    
+    if (objc < 2) {
+        Tcl_WrongNumArgs(interp, 1, objv, "cmd ?arg ...?");
+        return TCL_ERROR;
+    }
+
+    slaveInterp = (Tcl_Interp *) clientData;
+    if (slaveInterp == (Tcl_Interp *) NULL) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "interpreter ", Tcl_GetStringFromObj(objv[0], &len),
+                " has been deleted", (char *) NULL);
+	return TCL_ERROR;
+    }
+
+    slavePtr = (Slave *) Tcl_GetAssocData(slaveInterp,
+            "tclSlaveRecord", NULL);
+    if (slavePtr == (Slave *) NULL) {
+        panic("SlaveObjectCmd: could not find slave record");
+    }
+
+    result = Tcl_GetIndexFromObj(interp, objv[1], subCmds, "option",
+            0, (int *) &index);
+    if (result != TCL_OK) {
+        return result;
+    }
+
+    switch (index) {
+        case IAliasIdx:
+            return SlaveAliasHelper(interp, slaveInterp, slavePtr, objc, objv);
+        case IAliasesIdx:
+            return SlaveAliasesHelper(interp, slaveInterp, slavePtr,
+                    objc, objv);
+        case IEvalIdx:
+            return SlaveEvalHelper(interp, slaveInterp, slavePtr, objc, objv);
+        case IExposeIdx:
+            return SlaveExposeHelper(interp, slaveInterp, slavePtr,
+                    objc, objv);
+        case IHideIdx:
+            return SlaveHideHelper(interp, slaveInterp, slavePtr,
+                    objc, objv);
+        case IHiddenIdx:
+            return SlaveHiddenHelper(interp, slaveInterp, slavePtr,
+                    objc, objv);
+        case IIsSafeIdx:
+            return SlaveIsSafeHelper(interp, slaveInterp, slavePtr,
+                    objc, objv);
+        case IInvokeHiddenIdx:
+            return SlaveInvokeHiddenHelper(interp, slaveInterp, slavePtr,
+                    objc, objv);
+        case IMarkTrustedIdx:
+            return SlaveMarkTrustedHelper(interp, slaveInterp, slavePtr,
+                    objc, objv);
+    }
+
+    return TCL_ERROR;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * SlaveObjectDeleteProc --
+ *
+ *	Invoked when an object command for a slave interpreter is deleted;
+ *	cleans up all state associated with the slave interpreter and destroys
+ *	the slave interpreter.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Cleans up all state associated with the slave interpreter and
+ *	destroys the slave interpreter.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+SlaveObjectDeleteProc(clientData)
+    ClientData clientData;		/* The SlaveRecord for the command. */
+{
+    Slave *slavePtr;			/* Interim storage for Slave record. */
+    Tcl_Interp *slaveInterp;		/* And for a slave interp. */
+
+    slaveInterp = (Tcl_Interp *) clientData;
+    slavePtr = (Slave *) Tcl_GetAssocData(slaveInterp, "tclSlaveRecord",NULL); 
+    if (slavePtr == (Slave *) NULL) {
+        panic("SlaveObjectDeleteProc: could not find slave record");
+    }
+
+    /*
+     * Delete the entry in the slave table in the master interpreter now.
+     * This is to avoid an infinite loop in the Master hash table cleanup in
+     * the master interpreter. This can happen if this slave is being deleted
+     * because the master is being deleted and the slave deletion is deferred
+     * because it is still active.
+     */
+
+    Tcl_DeleteHashEntry(slavePtr->slaveEntry);
+
+    /*
+     * Set to NULL so that when the slave record is cleaned up in the slave
+     * it does not try to delete the command causing all sorts of grief.
+     * See SlaveRecordDeleteProc().
+     */
+
+    slavePtr->interpCmd = NULL;
+
+    /*
+     * Destroy the interpreter - this will cause all the deleteProcs for
+     * all commands (including aliases) to run.
+     *
+     * NOTE: WE ASSUME THAT THE INTERPRETER HAS NOT BEEN DELETED YET!!
+     */
+
+    Tcl_DeleteInterp(slavePtr->slaveInterp);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * AliasCmd --
+ *
+ *	This is the procedure that services invocations of aliases in a
+ *	slave interpreter. One such command exists for each alias. When
+ *	invoked, this procedure redirects the invocation to the target
+ *	command in the master interpreter as designated by the Alias
+ *	record associated with this command.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	Causes forwarding of the invocation; all possible side effects
+ *	may occur as a result of invoking the command to which the
+ *	invocation is forwarded.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+AliasCmd(clientData, interp, objc, objv)
+    ClientData clientData;		/* Alias record. */
+    Tcl_Interp *interp;			/* Current interpreter. */
+    int objc;				/* Number of arguments. */
+    Tcl_Obj *CONST objv[];		/* Argument vector. */	
+{
+    Tcl_Interp *targetInterp;		/* Target for alias exec. */
+    Interp *iPtr;			/* Internal type of target. */
+    Alias *aliasPtr;			/* Describes the alias. */
+    Tcl_Command cmd;			/* The target command. */
+    Command *cmdPtr;			/* Points to target command. */
+    Tcl_Namespace *targetNsPtr;	        /* Target command's namespace. */
+    int result;				/* Result of execution. */
+    int i, j, addObjc;			/* Loop counters. */
+    int localObjc;			/* Local argument count. */
+    Tcl_Obj **localObjv;		/* Local argument vector. */
+    Tcl_Obj *namePtr, *objPtr;		/* Local object pointers. */
+    char *string;			/* Local object string rep. */
+    int len;				/* Dummy length arg. */
+    
+    aliasPtr = (Alias *) clientData;
+    targetInterp = aliasPtr->targetInterp;
+
+    /*
+     * Look for the target command in the global namespace of the target
+     * interpreter.
+     */
+
+    cmdPtr = NULL;
+    targetNsPtr = Tcl_GetGlobalNamespace(aliasPtr->targetInterp);
+    cmd = Tcl_FindCommand(targetInterp, aliasPtr->targetName,
+            targetNsPtr, /*flags*/ 0);
+    if (cmd != (Tcl_Command) NULL) {
+        cmdPtr = (Command *) cmd;
+    }
+
+    iPtr = (Interp *) targetInterp;
+
+    /*
+     * If the command does not exist, invoke "unknown" in the master.
+     */
+    
+    if (cmdPtr == NULL) {
+        addObjc = aliasPtr->objc;
+        localObjc = addObjc + objc + 1;
+        localObjv = (Tcl_Obj **) ckalloc((unsigned) sizeof(Tcl_Obj *)
+                * localObjc);
+        
+        localObjv[0] = Tcl_NewStringObj("unknown", -1);
+        localObjv[1] = Tcl_NewStringObj(aliasPtr->targetName, -1);
+        Tcl_IncrRefCount(localObjv[0]);
+        Tcl_IncrRefCount(localObjv[1]);
+        
+        for (i = 0, j = 2; i < addObjc; i++, j++) {
+            localObjv[j] = aliasPtr->objv[i];
+        }
+        for (i = 1; i < objc; i++, j++) {
+            localObjv[j] = objv[i];
+        }
+        Tcl_Preserve((ClientData) targetInterp);
+        result = TclObjInvoke(targetInterp, localObjc, localObjv, 0);
+
+        Tcl_DecrRefCount(localObjv[0]);
+        Tcl_DecrRefCount(localObjv[1]);
+        
+        ckfree((char *) localObjv);
+        
+        if (targetInterp != interp) {
+            if (result == TCL_ERROR) {
+                
+                /*
+                 * An error occurred, so transfer error information from
+                 * the target interpreter back to our interpreter.
+                 */
+
+                if (!(iPtr->flags & ERR_ALREADY_LOGGED)) {
+                    Tcl_AddErrorInfo((Tcl_Interp *) iPtr, "");
+                }
+                iPtr->flags &= (~(ERR_ALREADY_LOGGED));
+
+                Tcl_ResetResult(interp);
+                namePtr = Tcl_NewStringObj("errorInfo", -1);
+                objPtr = Tcl_ObjGetVar2(targetInterp, namePtr,
+                        (Tcl_Obj *) NULL, TCL_GLOBAL_ONLY);
+                string = Tcl_GetStringFromObj(objPtr, &len);
+                Tcl_AddObjErrorInfo(interp, string, len);
+                Tcl_SetVar2(interp, "errorCode", (char *) NULL,
+                        Tcl_GetVar2(targetInterp, "errorCode", (char *)
+                                NULL, TCL_GLOBAL_ONLY),
+                        TCL_GLOBAL_ONLY);
+                Tcl_DecrRefCount(namePtr);
+            }
+
+            /*
+             * Transfer the result from the target interpreter to the
+             * calling interpreter.
+             */
+            
+            Tcl_SetObjResult(interp, Tcl_GetObjResult(targetInterp));
+            Tcl_ResetResult(targetInterp);
+        }
+
+	Tcl_Release((ClientData) targetInterp);
+        return result;
+    }
+
+    /*
+     * Otherwise invoke the regular target command.
+     */
+    
+    if (aliasPtr->objc <= 0) {
+        localObjv = (Tcl_Obj **) objv;
+        localObjc = objc;
+    } else {
+        addObjc = aliasPtr->objc;
+        localObjc = objc + addObjc;
+        localObjv =
+            (Tcl_Obj **) ckalloc((unsigned) sizeof(Tcl_Obj *) * localObjc);
+        localObjv[0] = objv[0];
+        for (i = 0, j = 1; i < addObjc; i++, j++) {
+            localObjv[j] = aliasPtr->objv[i];
+        }
+        for (i = 1; i < objc; i++, j++) {
+            localObjv[j] = objv[i];
+        }
+    }
+
+    iPtr->numLevels++;
+    Tcl_Preserve((ClientData) targetInterp);
+
+    /*
+     * Reset the interpreter to its clean state; we do not know what state
+     * it is in now..
+     */
+    
+    Tcl_ResetResult(targetInterp);
+    result = (cmdPtr->objProc)(cmdPtr->objClientData, targetInterp,
+            localObjc, localObjv);
+
+    iPtr->numLevels--;
+    
+    /*
+     * Check if we are at the bottom of the stack for the target interpreter.
+     * If so, check for special return codes.
+     */
+    
+    if (iPtr->numLevels == 0) {
+	if (result == TCL_RETURN) {
+	    result = TclUpdateReturnInfo(iPtr);
+	}
+	if ((result != TCL_OK) && (result != TCL_ERROR)) {
+	    Tcl_ResetResult(targetInterp);
+	    if (result == TCL_BREAK) {
+                Tcl_SetObjResult(targetInterp,
+                        Tcl_NewStringObj("invoked \"break\" outside of a loop",
+                                -1));
+	    } else if (result == TCL_CONTINUE) {
+                Tcl_SetObjResult(targetInterp,
+                        Tcl_NewStringObj(
+                            "invoked \"continue\" outside of a loop",
+                            -1));
+	    } else {
+                char buf[128];
+
+                sprintf(buf, "command returned bad code: %d", result);
+                Tcl_SetObjResult(targetInterp, Tcl_NewStringObj(buf, -1));
+	    }
+	    result = TCL_ERROR;
+	}
+    }
+
+    /*
+     * Clean up any locally allocated argument vector structure.
+     */
+    
+    if (localObjv != objv) {
+        ckfree((char *) localObjv);
+    }
+    
+    /*
+     * Move the result from the target interpreter to the invoking
+     * interpreter if they are different.
+     *
+     * Note: We cannot use aliasPtr any more because the alias may have
+     * been deleted.
+     */
+
+    if (interp != targetInterp) {
+        if (result == TCL_ERROR) {
+
+            /*
+             * An error occurred, so transfer the error information from
+             * the target interpreter back to our interpreter.
+             */
+
+            if (!(iPtr->flags & ERR_ALREADY_LOGGED)) {
+                Tcl_AddErrorInfo(targetInterp, "");
+            }
+            iPtr->flags &= (~(ERR_ALREADY_LOGGED));
+            
+            Tcl_ResetResult(interp);
+            namePtr = Tcl_NewStringObj("errorInfo", -1);
+            objPtr = Tcl_ObjGetVar2(targetInterp, namePtr, (Tcl_Obj *) NULL,
+                    TCL_GLOBAL_ONLY);
+            string = Tcl_GetStringFromObj(objPtr, &len);
+            Tcl_AddObjErrorInfo(interp, string, len);
+            Tcl_SetVar2(interp, "errorCode", (char *) NULL,
+                    Tcl_GetVar2(targetInterp, "errorCode", (char *) NULL,
+                            TCL_GLOBAL_ONLY),
+                    TCL_GLOBAL_ONLY);
+            Tcl_DecrRefCount(namePtr);
+        }
+
+	/*
+         * Move the result object from one interpreter to the
+         * other.
+         */
+                
+        Tcl_SetObjResult(interp, Tcl_GetObjResult(targetInterp));
+        Tcl_ResetResult(targetInterp);
+    }
+    Tcl_Release((ClientData) targetInterp);
+    return result;        
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * AliasCmdDeleteProc --
+ *
+ *	Is invoked when an alias command is deleted in a slave. Cleans up
+ *	all storage associated with this alias.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Deletes the alias record and its entry in the alias table for
+ *	the interpreter.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+AliasCmdDeleteProc(clientData)
+    ClientData clientData;		/* The alias record for this alias. */
+{
+    Alias *aliasPtr;			/* Alias record for alias to delete. */
+    Target *targetPtr;			/* Record for target of this alias. */
+    int i;				/* Loop counter. */
+
+    aliasPtr = (Alias *) clientData;
+    
+    targetPtr = (Target *) Tcl_GetHashValue(aliasPtr->targetEntry);
+    ckfree((char *) targetPtr);
+    Tcl_DeleteHashEntry(aliasPtr->targetEntry);
+
+    ckfree((char *) aliasPtr->targetName);
+    ckfree((char *) aliasPtr->aliasName);
+    for (i = 0; i < aliasPtr->objc; i++) {
+        Tcl_DecrRefCount(aliasPtr->objv[i]);
+    }
+    if (aliasPtr->objv != (Tcl_Obj **) NULL) {
+        ckfree((char *) aliasPtr->objv);
+    }
+
+    Tcl_DeleteHashEntry(aliasPtr->aliasEntry);
+
+    ckfree((char *) aliasPtr);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * MasterRecordDeleteProc -
+ *
+ *	Is invoked when an interpreter (which is using the "interp" facility)
+ *	is deleted, and it cleans up the storage associated with the
+ *	"tclMasterRecord" assoc-data entry.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Cleans up storage.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+MasterRecordDeleteProc(clientData, interp)
+    ClientData	clientData;		/* Master record for deleted interp. */
+    Tcl_Interp *interp;			/* Interpreter being deleted. */
+{
+    Target *targetPtr;			/* Loop variable. */
+    Tcl_HashEntry *hPtr;		/* Search element. */
+    Tcl_HashSearch hSearch;		/* Search record (internal). */
+    Slave *slavePtr;			/* Loop variable. */
+    Master *masterPtr;			/* Interim storage. */
+
+    masterPtr = (Master *) clientData;
+    for (hPtr = Tcl_FirstHashEntry(&(masterPtr->slaveTable), &hSearch);
+         hPtr != NULL;
+         hPtr = Tcl_NextHashEntry(&hSearch)) {
+        slavePtr = (Slave *) Tcl_GetHashValue(hPtr);
+        (void) Tcl_DeleteCommandFromToken(interp, slavePtr->interpCmd);
+    }
+    Tcl_DeleteHashTable(&(masterPtr->slaveTable));
+
+    for (hPtr = Tcl_FirstHashEntry(&(masterPtr->targetTable), &hSearch);
+         hPtr != NULL;
+         hPtr = Tcl_FirstHashEntry(&(masterPtr->targetTable), &hSearch)) {
+        targetPtr = (Target *) Tcl_GetHashValue(hPtr);
+        (void) Tcl_DeleteCommandFromToken(targetPtr->slaveInterp,
+	        targetPtr->slaveCmd);
+    }
+    Tcl_DeleteHashTable(&(masterPtr->targetTable));
+
+    ckfree((char *) masterPtr);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * SlaveRecordDeleteProc --
+ *
+ *	Is invoked when an interpreter (which is using the interp facility)
+ *	is deleted, and it cleans up the storage associated with the
+ *	tclSlaveRecord assoc-data entry.
+ *
+ * Results:
+ *	None
+ *
+ * Side effects:
+ *	Cleans up storage.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+SlaveRecordDeleteProc(clientData, interp)
+    ClientData	clientData;		/* Slave record for deleted interp. */
+    Tcl_Interp *interp;			/* Interpreter being deleted. */
+{
+    Slave *slavePtr;			/* Interim storage. */
+    Alias *aliasPtr;
+    Tcl_HashTable *hTblPtr;
+    Tcl_HashEntry *hPtr;
+    Tcl_HashSearch hSearch;
+    
+    slavePtr = (Slave *) clientData;
+
+    /*
+     * In every case that we call SetAssocData on "tclSlaveRecord",
+     * slavePtr is not NULL. Otherwise we panic.
+     */
+
+    if (slavePtr == NULL) {
+	panic("SlaveRecordDeleteProc: NULL slavePtr");
+    }
+
+    if (slavePtr->interpCmd != (Tcl_Command) NULL) {
+	Command *cmdPtr = (Command *) slavePtr->interpCmd;
+
+	/*
+	 * The interpCmd has not been deleted in the master yet,  since
+	 * it's callback sets interpCmd to NULL.
+	 *
+	 * Probably Tcl_DeleteInterp() was called on this interpreter directly,
+	 * rather than via "interp delete", or equivalent (deletion of the
+	 * command in the master).
+	 *
+	 * Perform the cleanup done by SlaveObjectDeleteProc() directly,
+	 * and turn off the callback now (since we are about to free slavePtr
+	 * and this interpreter is going away, while the deletion of commands
+	 * in the master may be deferred).
+	 */
+
+	Tcl_DeleteHashEntry(slavePtr->slaveEntry);
+	cmdPtr->clientData = NULL;
+	cmdPtr->deleteProc = NULL;
+	cmdPtr->deleteData = NULL;
+
+        Tcl_DeleteCommandFromToken(slavePtr->masterInterp,
+	        slavePtr->interpCmd);
+    }
+
+    /*
+     * If there are any aliases, delete those now. This removes any
+     * dependency on the order of deletion between commands and the
+     * slave record.
+     */
+
+    hTblPtr = (Tcl_HashTable *) &(slavePtr->aliasTable);
+    for (hPtr = Tcl_FirstHashEntry(hTblPtr, &hSearch);
+             hPtr != (Tcl_HashEntry *) NULL;
+             hPtr = Tcl_FirstHashEntry(hTblPtr, &hSearch)) {
+        aliasPtr = (Alias *) Tcl_GetHashValue(hPtr);
+
+        /*
+         * The call to Tcl_DeleteCommand will release the storage
+         * occupied by the hash entry and the alias record.
+         */
+
+        Tcl_DeleteCommandFromToken(interp, aliasPtr->slaveCmd);
+    }
+        
+    /*
+     * Finally dispose of the hash table and the slave record.
+     */
+
+    Tcl_DeleteHashTable(hTblPtr);
+    ckfree((char *) slavePtr);    
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclInterpInit --
+ *
+ *	Initializes the invoking interpreter for using the "interp"
+ *	facility. This is called from inside Tcl_Init.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Adds the "interp" command to an interpreter and initializes several
+ *	records in the associated data of the invoking interpreter.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclInterpInit(interp)
+    Tcl_Interp *interp;			/* Interpreter to initialize. */
+{
+    Master *masterPtr;			/* Its Master record. */
+    Slave *slavePtr;			/* And its slave record. */
+
+    masterPtr = (Master *) ckalloc((unsigned) sizeof(Master));
+
+    Tcl_InitHashTable(&(masterPtr->slaveTable), TCL_STRING_KEYS);
+    Tcl_InitHashTable(&(masterPtr->targetTable), TCL_ONE_WORD_KEYS);
+
+    (void) Tcl_SetAssocData(interp, "tclMasterRecord", MasterRecordDeleteProc,
+            (ClientData) masterPtr);
+
+    slavePtr = (Slave *) ckalloc((unsigned) sizeof(Slave));
+
+    slavePtr->masterInterp = (Tcl_Interp *) NULL;
+    slavePtr->slaveEntry = (Tcl_HashEntry *) NULL;
+    slavePtr->slaveInterp = interp;
+    slavePtr->interpCmd = (Tcl_Command) NULL;
+    Tcl_InitHashTable(&(slavePtr->aliasTable), TCL_STRING_KEYS);
+
+    (void) Tcl_SetAssocData(interp, "tclSlaveRecord", SlaveRecordDeleteProc,
+            (ClientData) slavePtr);
+    
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_IsSafe --
+ *
+ *	Determines whether an interpreter is safe
+ *
+ * Results:
+ *	1 if it is safe, 0 if it is not.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_IsSafe(interp)
+    Tcl_Interp *interp;		/* Is this interpreter "safe" ? */
+{
+    Interp *iPtr;
+
+    if (interp == (Tcl_Interp *) NULL) {
+        return 0;
+    }
+    iPtr = (Interp *) interp;
+
+    return ( (iPtr->flags) & SAFE_INTERP ) ? 1 : 0 ;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_CreateSlave --
+ *
+ *	Creates a slave interpreter. The slavePath argument denotes the
+ *	name of the new slave relative to the current interpreter; the
+ *	slave is a direct descendant of the one-before-last component of
+ *	the path, e.g. it is a descendant of the current interpreter if
+ *	the slavePath argument contains only one component. Optionally makes
+ *	the slave interpreter safe.
+ *
+ * Results:
+ *	Returns the interpreter structure created, or NULL if an error
+ *	occurred.
+ *
+ * Side effects:
+ *	Creates a new interpreter and a new interpreter object command in
+ *	the interpreter indicated by the slavePath argument.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Interp *
+Tcl_CreateSlave(interp, slavePath, isSafe)
+    Tcl_Interp *interp;		/* Interpreter to start search at. */
+    char *slavePath;		/* Name of slave to create. */
+    int isSafe;			/* Should new slave be "safe" ? */
+{
+    Master *masterPtr;			/* Master record for same. */
+
+    if ((interp == (Tcl_Interp *) NULL) || (slavePath == (char *) NULL)) {
+        return NULL;
+    }
+    masterPtr = (Master *) Tcl_GetAssocData(interp, "tclMasterRecord",
+            NULL); 
+    if (masterPtr == (Master *) NULL) {
+        panic("CreatSlave: could not find master record");
+    }
+    return CreateSlave(interp, masterPtr, slavePath, isSafe);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_GetSlave --
+ *
+ *	Finds a slave interpreter by its path name.
+ *
+ * Results:
+ *	Returns a Tcl_Interp * for the named interpreter or NULL if not
+ *	found.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Interp *
+Tcl_GetSlave(interp, slavePath)
+    Tcl_Interp *interp;		/* Interpreter to start search from. */
+    char *slavePath;		/* Path of slave to find. */
+{
+    Master *masterPtr;		/* Interim storage for Master record. */
+
+    if ((interp == (Tcl_Interp *) NULL) || (slavePath == (char *) NULL)) {
+        return NULL;
+    }
+    masterPtr = (Master *) Tcl_GetAssocData(interp, "tclMasterRecord", NULL);
+    if (masterPtr == (Master *) NULL) {
+        panic("Tcl_GetSlave: could not find master record");
+    }
+    return GetInterp(interp, masterPtr, slavePath, NULL);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_GetMaster --
+ *
+ *	Finds the master interpreter of a slave interpreter.
+ *
+ * Results:
+ *	Returns a Tcl_Interp * for the master interpreter or NULL if none.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+Tcl_Interp *
+Tcl_GetMaster(interp)
+    Tcl_Interp *interp;		/* Get the master of this interpreter. */
+{
+    Slave *slavePtr;		/* Slave record of this interpreter. */
+
+    if (interp == (Tcl_Interp *) NULL) {
+        return NULL;
+    }
+    slavePtr = (Slave *) Tcl_GetAssocData(interp, "tclSlaveRecord", NULL);
+    if (slavePtr == (Slave *) NULL) {
+        return NULL;
+    }
+    return slavePtr->masterInterp;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_CreateAlias --
+ *
+ *	Creates an alias between two interpreters.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	Creates a new alias, manipulates the result field of slaveInterp.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_CreateAlias(slaveInterp, slaveCmd, targetInterp, targetCmd, argc, argv)
+    Tcl_Interp *slaveInterp;		/* Interpreter for source command. */
+    char *slaveCmd;			/* Command to install in slave. */
+    Tcl_Interp *targetInterp;		/* Interpreter for target command. */
+    char *targetCmd;			/* Name of target command. */
+    int argc;				/* How many additional arguments? */
+    char **argv;			/* These are the additional args. */
+{
+    Master *masterPtr;			/* Master record for target interp. */
+    Tcl_Obj **objv;
+    int i;
+    int result;
+    
+    if ((slaveInterp == (Tcl_Interp *) NULL) ||
+            (targetInterp == (Tcl_Interp *) NULL) ||
+            (slaveCmd == (char *) NULL) ||
+            (targetCmd == (char *) NULL)) {
+        return TCL_ERROR;
+    }
+    masterPtr = (Master *) Tcl_GetAssocData(targetInterp, "tclMasterRecord",
+            NULL);
+    if (masterPtr == (Master *) NULL) {
+        panic("Tcl_CreateAlias: could not find master record");
+    }
+    objv = (Tcl_Obj **) ckalloc((unsigned) sizeof(Tcl_Obj *) * argc);
+    for (i = 0; i < argc; i++) {
+        objv[i] = Tcl_NewStringObj(argv[i], -1);
+        Tcl_IncrRefCount(objv[i]);
+    }
+    
+    result = AliasCreationHelper(slaveInterp, slaveInterp, targetInterp,
+            masterPtr, slaveCmd, targetCmd, argc, objv);
+
+    ckfree((char *) objv);
+
+    return result;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_CreateAliasObj --
+ *
+ *	Object version: Creates an alias between two interpreters.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	Creates a new alias.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_CreateAliasObj(slaveInterp, slaveCmd, targetInterp, targetCmd, objc, objv)
+    Tcl_Interp *slaveInterp;		/* Interpreter for source command. */
+    char *slaveCmd;			/* Command to install in slave. */
+    Tcl_Interp *targetInterp;		/* Interpreter for target command. */
+    char *targetCmd;			/* Name of target command. */
+    int objc;				/* How many additional arguments? */
+    Tcl_Obj *CONST objv[];		/* Argument vector. */
+{
+    Master *masterPtr;			/* Master record for target interp. */
+
+    if ((slaveInterp == (Tcl_Interp *) NULL) ||
+            (targetInterp == (Tcl_Interp *) NULL) ||
+            (slaveCmd == (char *) NULL) ||
+            (targetCmd == (char *) NULL)) {
+        return TCL_ERROR;
+    }
+    masterPtr = (Master *) Tcl_GetAssocData(targetInterp, "tclMasterRecord",
+            NULL);
+    if (masterPtr == (Master *) NULL) {
+        panic("Tcl_CreateAlias: could not find master record");
+    }
+    return AliasCreationHelper(slaveInterp, slaveInterp, targetInterp,
+            masterPtr, slaveCmd, targetCmd, objc, objv);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_GetAlias --
+ *
+ *	Gets information about an alias.
+ *
+ * Results:
+ *	A standard Tcl result. 
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_GetAlias(interp, aliasName, targetInterpPtr, targetNamePtr, argcPtr,
+        argvPtr)
+    Tcl_Interp *interp;			/* Interp to start search from. */
+    char *aliasName;			/* Name of alias to find. */
+    Tcl_Interp **targetInterpPtr;	/* (Return) target interpreter. */
+    char **targetNamePtr;		/* (Return) name of target command. */
+    int *argcPtr;			/* (Return) count of addnl args. */
+    char ***argvPtr;			/* (Return) additional arguments. */
+{
+    Slave *slavePtr;			/* Slave record for slave interp. */
+    Tcl_HashEntry *hPtr;		/* Search element. */
+    Alias *aliasPtr;			/* Storage for alias found. */
+    int len;
+    int i;
+
+    if ((interp == (Tcl_Interp *) NULL) || (aliasName == (char *) NULL)) {
+        return TCL_ERROR;
+    }
+    slavePtr = (Slave *) Tcl_GetAssocData(interp, "tclSlaveRecord", NULL);
+    if (slavePtr == (Slave *) NULL) {
+        panic("Tcl_GetAlias: could not find slave record");
+    }
+    hPtr = Tcl_FindHashEntry(&(slavePtr->aliasTable), aliasName);
+    if (hPtr == (Tcl_HashEntry *) NULL) {
+        Tcl_AppendResult(interp, "alias \"", aliasName, "\" not found",
+                (char *) NULL);
+        return TCL_ERROR;
+    }
+    aliasPtr = (Alias *) Tcl_GetHashValue(hPtr);
+    if (targetInterpPtr != (Tcl_Interp **) NULL) {
+        *targetInterpPtr = aliasPtr->targetInterp;
+    }
+    if (targetNamePtr != (char **) NULL) {
+        *targetNamePtr = aliasPtr->targetName;
+    }
+    if (argcPtr != (int *) NULL) {
+        *argcPtr = aliasPtr->objc;
+    }
+    if (argvPtr != (char ***) NULL) {
+        *argvPtr = (char **) ckalloc((unsigned) sizeof(char *) *
+                aliasPtr->objc);
+        for (i = 0; i < aliasPtr->objc; i++) {
+            *argvPtr[i] = Tcl_GetStringFromObj(aliasPtr->objv[i], &len);
+        }
+    }
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_ObjGetAlias --
+ *
+ *	Object version: Gets information about an alias.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_GetAliasObj(interp, aliasName, targetInterpPtr, targetNamePtr, objcPtr,
+        objvPtr)
+    Tcl_Interp *interp;			/* Interp to start search from. */
+    char *aliasName;			/* Name of alias to find. */
+    Tcl_Interp **targetInterpPtr;	/* (Return) target interpreter. */
+    char **targetNamePtr;		/* (Return) name of target command. */
+    int *objcPtr;			/* (Return) count of addnl args. */
+    Tcl_Obj ***objvPtr;			/* (Return) additional args. */
+{
+    Slave *slavePtr;			/* Slave record for slave interp. */
+    Tcl_HashEntry *hPtr;		/* Search element. */
+    Alias *aliasPtr;			/* Storage for alias found. */
+
+    if ((interp == (Tcl_Interp *) NULL) || (aliasName == (char *) NULL)) {
+        return TCL_ERROR;
+    }
+    slavePtr = (Slave *) Tcl_GetAssocData(interp, "tclSlaveRecord", NULL);
+    if (slavePtr == (Slave *) NULL) {
+        panic("Tcl_GetAlias: could not find slave record");
+    }
+    hPtr = Tcl_FindHashEntry(&(slavePtr->aliasTable), aliasName);
+    if (hPtr == (Tcl_HashEntry *) NULL) {
+        Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
+                "alias \"", aliasName, "\" not found", (char *) NULL);
+        return TCL_ERROR;
+    }
+    aliasPtr = (Alias *) Tcl_GetHashValue(hPtr);
+    if (targetInterpPtr != (Tcl_Interp **) NULL) {
+        *targetInterpPtr = aliasPtr->targetInterp;
+    }
+    if (targetNamePtr != (char **) NULL) {
+        *targetNamePtr = aliasPtr->targetName;
+    }
+    if (objcPtr != (int *) NULL) {
+        *objcPtr = aliasPtr->objc;
+    }
+    if (objvPtr != (Tcl_Obj ***) NULL) {
+        *objvPtr = aliasPtr->objv;
+    }
+    return TCL_OK;
+}