Index: TODO
===================================================================
diff -u -r2767762e5ef68bee6e82cbff0d69f54b01c37a13 -rf2c0f8e055015e58f3fa7bd338c872a2b7d76113
--- TODO	(.../TODO)	(revision 2767762e5ef68bee6e82cbff0d69f54b01c37a13)
+++ TODO	(.../TODO)	(revision f2c0f8e055015e58f3fa7bd338c872a2b7d76113)
@@ -2003,6 +2003,11 @@
 - xotcl2.tcl: fix the default init handler
 - nsf.c: provide warnings when unchecked parameter values might conflict with nonpos args
 
+- provide a generic logging interface
+  * predefined for plain Tcl and aolserver/naviserver
+  * C-level: NsfLog()
+  * Tcl-level: ::nsf::log
+
 TODO:
 
 - "-returns" 
Index: generic/nsf.c
===================================================================
diff -u -r2767762e5ef68bee6e82cbff0d69f54b01c37a13 -rf2c0f8e055015e58f3fa7bd338c872a2b7d76113
--- generic/nsf.c	(.../nsf.c)	(revision 2767762e5ef68bee6e82cbff0d69f54b01c37a13)
+++ generic/nsf.c	(.../nsf.c)	(revision f2c0f8e055015e58f3fa7bd338c872a2b7d76113)
@@ -274,7 +274,55 @@
 static int NextSearchAndInvoke(Tcl_Interp *interp,
 			       CONST char *methodName, int objc, Tcl_Obj *CONST objv[],
 			       NsfCallStackContent *cscPtr, int freeArgumentVector);
+
 /*
+ *----------------------------------------------------------------------
+ *
+ * NsfLog --
+ *
+ *      Produce a formatted warning by calling an external function
+ *      ::nsf::log. It is defined static to allow for inlining.
+ *
+ * Results:
+ *      None.
+ *
+ * Side effects:
+ *      None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+NsfLog(Tcl_Interp *interp, int requiredLevel, CONST char *fmt, ...) {
+  va_list ap;
+
+  if (RUNTIME_STATE(interp)->debugLevel >= requiredLevel) {
+    CONST char *level = requiredLevel == NSF_LOG_WARN ? "Warning" : "Inform";
+    Tcl_DString cmdString, ds;
+
+    Tcl_DStringInit(&ds);
+    va_start(ap, fmt);
+    NsfDStringPrintf(&ds, fmt, ap);
+    va_end(ap);
+
+    Tcl_DStringInit(&cmdString);
+    Tcl_DStringAppendElement(&cmdString, "nsf::log");
+    Tcl_DStringAppendElement(&cmdString, level);
+    Tcl_DStringAppendElement(&cmdString, Tcl_DStringValue(&ds));
+
+    int result = Tcl_EvalEx(interp, Tcl_DStringValue(&cmdString), Tcl_DStringLength(&cmdString), 0);
+    if (result == TCL_ERROR) {
+      static char cmdString[] =
+	"puts stderr \"Error in logger\n\
+      $::errorCode $::errorInfo\"";
+      Tcl_EvalEx(interp, cmdString, -1, 0);
+    }
+    Tcl_DStringFree(&cmdString);
+    Tcl_DStringFree(&ds);
+  }
+}
+
+/*
  * argv parsing
  */
 
@@ -2832,16 +2880,16 @@
       } else {
 	if (object->teardown && !(object->flags & NSF_DESTROY_CALLED)) {
 	  int result = DispatchDestroyMethod(interp, object, 0);
+
 	  if (result != TCL_OK) {
-	    if (RUNTIME_STATE(interp)->debugLevel > 1) {
-	      fprintf(stderr, "Warning: destroy failed for object %s, perform low level deletion\n",
-		      ObjectName(object));
-	    }
 	    /*
 	     * The destroy method failed. However, we have to remove
 	     * the command anyway, since its parent is currently being
 	     * deleted.
 	     */
+	    NsfLog(interp, NSF_LOG_INFORM, "Destroy failed for object %s, perform low level deletion",
+		   ObjectName(object));
+
 	    if (object->teardown) {
 	      CallStackDestroyObject(interp, object);
 	    }
@@ -4529,19 +4577,15 @@
     int new;
 
     if (inst->flags & NSF_TCL_DELETE) {
-      if (RUNTIME_STATE(interp)->debugLevel > 1) {
-	fprintf(stderr, "Warning: Object %s is apparently deleted\n", ObjectName(inst));
-      }
+      NsfLog(interp, NSF_LOG_INFORM, "Object %s is apparently deleted", ObjectName(inst));
       continue;
     }
 
     cmdPtr = (Command *)inst->id;
     assert(cmdPtr);
 
     if (cmdPtr && (cmdPtr->nsPtr->flags & NS_DYING)) {
-      if (RUNTIME_STATE(interp)->debugLevel > 0) {
-	fprintf(stderr, "Warning: Namespace of %s is apparently deleted\n", ObjectName(inst));
-      }
+      NsfLog(interp, NSF_LOG_WARN, "Namespace of %s is apparently deleted", ObjectName(inst));
       continue;
     }
 
@@ -7531,9 +7575,7 @@
 	 *  {1} Class ::State
 	 *  {2} Class ::State -parameter x
 	 */
-	if (RUNTIME_STATE(interp)->debugLevel > 1) {
-	  fprintf(stderr, "Warning: don't invoke object %s this way. Register object via alias...\n", methodName);
-	}
+	NsfLog(interp, NSF_LOG_INFORM, "Don't invoke object %s this way. Register object via alias...", methodName);
 	cmd = NULL;
 
       } else if (IsClassNsName(methodName)) {
@@ -7579,11 +7621,9 @@
     NsfObject *lastSelf = GetSelfObj(interp);
 
     if (object != lastSelf) {
-      if (RUNTIME_STATE(interp)->debugLevel > 0) {
-	fprintf(stderr, "Warning: '%s %s' fails since method %s.%s is protected.\n", 
-		ObjectName(object), methodName, 
-		cl ? ClassName(cl) : ObjectName(object), methodName);
-      }
+      NsfLog(interp, NSF_LOG_WARN, "'%s %s' fails since method %s.%s is protected", 
+	     ObjectName(object), methodName, 
+	     cl ? ClassName(cl) : ObjectName(object), methodName);
       /* reset cmd, since it is still unknown */
       cmd = NULL;
     }
@@ -7947,8 +7987,8 @@
 	  && (pPtr->flags & NSF_ARG_CHECK_NONPOS) 
 	  && isalpha(*(value+1)) 
 	  && strchr(value+1, ' ') == 0) {
-	fprintf(stderr, "Warning: value '%s' of parameter %s could be a non-positional argument\n",
-		value, pPtr->name);
+	NsfLog(interp, NSF_LOG_WARN, "Value '%s' of parameter %s could be a non-positional argument",
+	       value, pPtr->name);
       }
     } 
 
@@ -8457,21 +8497,18 @@
     if (cmd == NULL) {
       if (paramPtr->converter == ConvertViaCmd) {
 
-	if (RUNTIME_STATE(interp)->debugLevel > 0) {
-	  fprintf(stderr, "Warning: could not find value checker %s defined on %s\n",
-		  converterNameString, ObjectName(paramObj));
-	}
+	NsfLog(interp, NSF_LOG_WARN, "Could not find value checker %s defined on %s",
+	       converterNameString, ObjectName(paramObj));
+
         paramPtr->flags |= NSF_ARG_CURRENTLY_UNKNOWN;
         /* TODO: for the time being, we do not return an error here */
       }
     } else if (paramPtr->converter != ConvertViaCmd &&
                strcmp(ObjStr(paramPtr->slotObj),
 		      NsfGlobalStrings[NSF_METHOD_PARAMETER_SLOT_OBJ]) != 0) {
 
-      if (RUNTIME_STATE(interp)->debugLevel > 0) {
-	fprintf(stderr, "Warning: checker method %s defined on %s shadows built-in converter\n",
-		converterNameString, ObjectName(paramObj));
-      }
+      NsfLog(interp, NSF_LOG_WARN, "Checker method %s defined on %s shadows built-in converter",
+	     converterNameString, ObjectName(paramObj));
 
       if (paramPtr->converterName == NULL) {
         paramPtr->converterName = converterNameObj;
@@ -12499,12 +12536,9 @@
 	  }
 	} else {
 	  /* should never happen */
-	  if (RUNTIME_STATE(interp)->debugLevel > 0) {
-	    fprintf(stderr, "Warning: Could not obtain alias definition for %s. "
-		    "Maybe someone deleted the alias %s for object %s?\n",
-		    methodName,
-		    methodName, ObjectName(regObject));
-	  }
+	  NsfLog(interp, NSF_LOG_WARN, "Could not obtain alias definition for %s. "
+		 "Maybe someone deleted the alias %s for object %s?",
+		 methodName, methodName, ObjectName(regObject));
 	  Tcl_ResetResult(interp);
 	}
       }
@@ -13329,14 +13363,12 @@
 
   GetClassFromObj(interp, object, &theobj, NULL);
   GetClassFromObj(interp, class, &thecls, NULL);
+
   if (theobj || thecls) {
-    
     ObjectSystemFree(interp, osPtr);
-    if (RUNTIME_STATE(interp)->debugLevel > 0) {
-      fprintf(stderr, "Warning: Base class exists already; ignoring definition.\n");
-    }
+    NsfLog(interp, NSF_LOG_WARN, "Base %s class exists already; ignoring definition", 
+	   theobj ? object : class);
     return TCL_OK;
-    /* fprintf(stderr, "CreateObjectSystem created base classes \n"); */
   }
 
   if (systemMethodsObj) {
@@ -17291,12 +17323,12 @@
    * value to ensure deletion.
    */
   if (object->refCount != 1) {
-    if (RUNTIME_STATE(interp)->debugLevel > 0) {
-      fprintf(stderr, "Warning: have to fix refcount for obj %p refcount %d",object, object->refCount);
-      if (object->refCount > 1) {
-	fprintf(stderr, " (name %s)", ObjectName(object));
-      }
-      fprintf(stderr, "\n");
+    if (object->refCount > 1) {
+      NsfLog(interp, NSF_LOG_WARN,  "Have to fix refcount for obj %p refcount %d  (name %s)",
+	     object, object->refCount, ObjectName(object));
+    } else {
+      NsfLog(interp, NSF_LOG_WARN,  "Have to fix refcount for obj %p refcount %d",
+	     object, object->refCount);
     }
     object->refCount = 1;
   }
Index: generic/nsf.decls
===================================================================
diff -u -r14965323980c2235c37b67ddbb19343ddbdaa41c -rf2c0f8e055015e58f3fa7bd338c872a2b7d76113
--- generic/nsf.decls	(.../nsf.decls)	(revision 14965323980c2235c37b67ddbb19343ddbdaa41c)
+++ generic/nsf.decls	(.../nsf.decls)	(revision f2c0f8e055015e58f3fa7bd338c872a2b7d76113)
@@ -43,7 +43,7 @@
     int NsfDeleteObject(Tcl_Interp *interp, struct Nsf_Object *obj)
 }
 declare 7 generic {
-    int NsfRemoveObjectMethod(Tcl_Interp *interp,struct Nsf_Object *obj, CONST char *nm)
+    int NsfRemoveObjectMethod(Tcl_Interp *interp, struct Nsf_Object *obj, CONST char *nm)
 }
 declare 8 generic {
     int NsfRemoveClassMethod(Tcl_Interp *interp, struct Nsf_Class *cl, CONST char *nm)
@@ -58,12 +58,12 @@
 }
 declare 11 generic {
     Tcl_Obj *Nsf_ObjSetVar2(struct Nsf_Object *obj,
-                 Tcl_Interp *interp,Tcl_Obj *name1,Tcl_Obj *name2,
-		 Tcl_Obj *value,int flgs)
+                 Tcl_Interp *interp, Tcl_Obj *name1, Tcl_Obj *name2,
+		 Tcl_Obj *value, int flgs)
 }
 declare 12 generic {
     Tcl_Obj *Nsf_ObjGetVar2(struct Nsf_Object *obj, 
-                 Tcl_Interp *interp,Tcl_Obj *name1,Tcl_Obj *name2,
+                 Tcl_Interp *interp, Tcl_Obj *name1, Tcl_Obj *name2,
 		 int flgs)
 }
 declare 13 generic {
@@ -78,59 +78,62 @@
     int NsfVarErrMsg(Tcl_Interp  *interp, ...)
 }
 declare 16 generic {
+    void NsfDStringPrintf(Tcl_DString *dsPtr, CONST char *fmt, va_list apSrc)
+}
+declare 17 generic {
     int NsfErrInProc (Tcl_Interp *interp, Tcl_Obj *objName,
 		Tcl_Obj *clName, CONST char *procName)
 }
-declare 17 generic {
+declare 18 generic {
    int NsfErrBadVal_(Tcl_Interp *interp, char *expected, char *value)
 }
-declare 18 generic {
+declare 19 generic {
     int NsfObjErrType(Tcl_Interp *interp, Tcl_Obj *nm, char *wt, char *parameterName)
 }
-declare 19 generic {
+declare 20 generic {
     void NsfStackDump (Tcl_Interp *interp)
 }
-declare 20 generic {
+declare 21 generic {
     void NsfSetObjClientData(Nsf_Object *obj, ClientData data)
 }
-declare 21 generic {
+declare 22 generic {
     ClientData NsfGetObjClientData(Nsf_Object *obj)
 }
-declare 22 generic {
+declare 23 generic {
     void NsfSetClassClientData(Nsf_Class *cl, ClientData data)
 }
-declare 23 generic {
+declare 24 generic {
     ClientData NsfGetClassClientData(Nsf_Class *cl)
 }
-declare 24 generic {
+declare 25 generic {
     void NsfRequireObjNamespace(Tcl_Interp *interp, Nsf_Object *obj)
 }
-declare 25 generic {
+declare 26 generic {
     int NsfErrBadVal(Tcl_Interp *interp, char *context, char *expected, CONST char *value)
 }
-declare 26 generic {
+declare 27 generic {
         int NsfNextObjCmd(ClientData cd, Tcl_Interp *interp, int objc, Tcl_Obj *CONST objv[])
 }
-declare 27 generic {
+declare 28 generic {
         int  NsfCallMethodWithArgs(ClientData cd, Tcl_Interp *interp, 
                 Tcl_Obj *method, Tcl_Obj *arg,
        	         int objc, Tcl_Obj *CONST objv[], int flags)
 }
-declare 28 generic {
+declare 29 generic {
     int NsfObjErrArgCnt(Tcl_Interp *interp, Tcl_Obj *cmdName, Tcl_Obj *methodName, 
                                      char *arglist)
 }
-declare 29 generic {
+declare 30 generic {
     int NsfAddObjectMethod(Tcl_Interp *interp, struct Nsf_Object *obj, 
                          CONST char *nm, Tcl_ObjCmdProc *proc,
 	                 ClientData cd, Tcl_CmdDeleteProc *dp, int flags)
 }
-declare 30 generic {
+declare 31 generic {
    int NsfAddClassMethod(Tcl_Interp *interp, struct Nsf_Class *cl, 
                          CONST char *nm, Tcl_ObjCmdProc *proc,
 	                 ClientData cd, Tcl_CmdDeleteProc *dp, int flags)
 }
-declare 31 generic {
+declare 32 generic {
     int NsfCreate(Tcl_Interp *in, Nsf_Class *class, Tcl_Obj *name, ClientData data,
             int objc, Tcl_Obj *CONST objv[])
 }
Index: generic/nsf.tcl
===================================================================
diff -u -r6c2e8f94be1ba335ff90d4b6b5132c98a9f5c242 -rf2c0f8e055015e58f3fa7bd338c872a2b7d76113
--- generic/nsf.tcl	(.../nsf.tcl)	(revision 6c2e8f94be1ba335ff90d4b6b5132c98a9f5c242)
+++ generic/nsf.tcl	(.../nsf.tcl)	(revision f2c0f8e055015e58f3fa7bd338c872a2b7d76113)
@@ -77,6 +77,19 @@
   }
   # initialize exit handler
   ::nsf::exithandler unset
+  
+  #
+  # logger
+  #
+  if {[info command ::ns_log] ne ""} {
+    proc ::nsf::log {level msg} {
+      ns_log $level "nsf: $msg"
+    }
+  } else {
+    proc ::nsf::log {level msg} {
+      puts stderr "$level: $msg"
+    }
+  }
 
   #
   # determine platform aware temp directory
Index: generic/nsfDecls.h
===================================================================
diff -u -r9b7a590f8f91f52d2d5934b7509eac5fcd7fb91e -rf2c0f8e055015e58f3fa7bd338c872a2b7d76113
--- generic/nsfDecls.h	(.../nsfDecls.h)	(revision 9b7a590f8f91f52d2d5934b7509eac5fcd7fb91e)
+++ generic/nsfDecls.h	(.../nsfDecls.h)	(revision f2c0f8e055015e58f3fa7bd338c872a2b7d76113)
@@ -115,100 +115,106 @@
 /* 15 */
 EXTERN int		NsfVarErrMsg(Tcl_Interp *interp, ...);
 #endif
+#ifndef NsfDStringPrintf_TCL_DECLARED
+#define NsfDStringPrintf_TCL_DECLARED
+/* 16 */
+EXTERN void		NsfDStringPrintf(Tcl_DString *dsPtr, CONST char *fmt,
+				va_list apSrc);
+#endif
 #ifndef NsfErrInProc_TCL_DECLARED
 #define NsfErrInProc_TCL_DECLARED
-/* 16 */
+/* 17 */
 EXTERN int		NsfErrInProc(Tcl_Interp *interp, Tcl_Obj *objName,
 				Tcl_Obj *clName, CONST char *procName);
 #endif
 #ifndef NsfErrBadVal__TCL_DECLARED
 #define NsfErrBadVal__TCL_DECLARED
-/* 17 */
+/* 18 */
 EXTERN int		NsfErrBadVal_(Tcl_Interp *interp, char *expected,
 				char *value);
 #endif
 #ifndef NsfObjErrType_TCL_DECLARED
 #define NsfObjErrType_TCL_DECLARED
-/* 18 */
+/* 19 */
 EXTERN int		NsfObjErrType(Tcl_Interp *interp, Tcl_Obj *nm,
 				char *wt, char *parameterName);
 #endif
 #ifndef NsfStackDump_TCL_DECLARED
 #define NsfStackDump_TCL_DECLARED
-/* 19 */
+/* 20 */
 EXTERN void		NsfStackDump(Tcl_Interp *interp);
 #endif
 #ifndef NsfSetObjClientData_TCL_DECLARED
 #define NsfSetObjClientData_TCL_DECLARED
-/* 20 */
+/* 21 */
 EXTERN void		NsfSetObjClientData(Nsf_Object *obj, ClientData data);
 #endif
 #ifndef NsfGetObjClientData_TCL_DECLARED
 #define NsfGetObjClientData_TCL_DECLARED
-/* 21 */
+/* 22 */
 EXTERN ClientData	NsfGetObjClientData(Nsf_Object *obj);
 #endif
 #ifndef NsfSetClassClientData_TCL_DECLARED
 #define NsfSetClassClientData_TCL_DECLARED
-/* 22 */
+/* 23 */
 EXTERN void		NsfSetClassClientData(Nsf_Class *cl, ClientData data);
 #endif
 #ifndef NsfGetClassClientData_TCL_DECLARED
 #define NsfGetClassClientData_TCL_DECLARED
-/* 23 */
+/* 24 */
 EXTERN ClientData	NsfGetClassClientData(Nsf_Class *cl);
 #endif
 #ifndef NsfRequireObjNamespace_TCL_DECLARED
 #define NsfRequireObjNamespace_TCL_DECLARED
-/* 24 */
+/* 25 */
 EXTERN void		NsfRequireObjNamespace(Tcl_Interp *interp,
 				Nsf_Object *obj);
 #endif
 #ifndef NsfErrBadVal_TCL_DECLARED
 #define NsfErrBadVal_TCL_DECLARED
-/* 25 */
+/* 26 */
 EXTERN int		NsfErrBadVal(Tcl_Interp *interp, char *context,
 				char *expected, CONST char *value);
 #endif
 #ifndef NsfNextObjCmd_TCL_DECLARED
 #define NsfNextObjCmd_TCL_DECLARED
-/* 26 */
+/* 27 */
 EXTERN int		NsfNextObjCmd(ClientData cd, Tcl_Interp *interp,
 				int objc, Tcl_Obj *CONST objv[]);
 #endif
 #ifndef NsfCallMethodWithArgs_TCL_DECLARED
 #define NsfCallMethodWithArgs_TCL_DECLARED
-/* 27 */
+/* 28 */
 EXTERN int		NsfCallMethodWithArgs(ClientData cd,
 				Tcl_Interp *interp, Tcl_Obj *method,
 				Tcl_Obj *arg, int objc,
 				Tcl_Obj *CONST objv[], int flags);
 #endif
 #ifndef NsfObjErrArgCnt_TCL_DECLARED
 #define NsfObjErrArgCnt_TCL_DECLARED
-/* 28 */
+/* 29 */
 EXTERN int		NsfObjErrArgCnt(Tcl_Interp *interp, Tcl_Obj *cmdName,
 				Tcl_Obj *methodName, char *arglist);
 #endif
 #ifndef NsfAddObjectMethod_TCL_DECLARED
 #define NsfAddObjectMethod_TCL_DECLARED
-/* 29 */
+/* 30 */
 EXTERN int		NsfAddObjectMethod(Tcl_Interp *interp,
 				struct Nsf_Object *obj, CONST char *nm,
 				Tcl_ObjCmdProc *proc, ClientData cd,
 				Tcl_CmdDeleteProc *dp, int flags);
 #endif
 #ifndef NsfAddClassMethod_TCL_DECLARED
 #define NsfAddClassMethod_TCL_DECLARED
-/* 30 */
+/* 31 */
 EXTERN int		NsfAddClassMethod(Tcl_Interp *interp,
 				struct Nsf_Class *cl, CONST char *nm,
 				Tcl_ObjCmdProc *proc, ClientData cd,
 				Tcl_CmdDeleteProc *dp, int flags);
 #endif
 #ifndef NsfCreate_TCL_DECLARED
 #define NsfCreate_TCL_DECLARED
-/* 31 */
+/* 32 */
 EXTERN int		NsfCreate(Tcl_Interp *in, Nsf_Class *class,
 				Tcl_Obj *name, ClientData data, int objc,
 				Tcl_Obj *CONST objv[]);
@@ -238,22 +244,23 @@
     int (*nsfUnsetInstVar2) (struct Nsf_Object *obj, Tcl_Interp *interp, CONST char *name1, CONST char *name2, int flgs); /* 13 */
     int (*nsfErrMsg) (Tcl_Interp *interp, char *msg, Tcl_FreeProc *type); /* 14 */
     int (*nsfVarErrMsg) (Tcl_Interp *interp, ...); /* 15 */
-    int (*nsfErrInProc) (Tcl_Interp *interp, Tcl_Obj *objName, Tcl_Obj *clName, CONST char *procName); /* 16 */
-    int (*nsfErrBadVal_) (Tcl_Interp *interp, char *expected, char *value); /* 17 */
-    int (*nsfObjErrType) (Tcl_Interp *interp, Tcl_Obj *nm, char *wt, char *parameterName); /* 18 */
-    void (*nsfStackDump) (Tcl_Interp *interp); /* 19 */
-    void (*nsfSetObjClientData) (Nsf_Object *obj, ClientData data); /* 20 */
-    ClientData (*nsfGetObjClientData) (Nsf_Object *obj); /* 21 */
-    void (*nsfSetClassClientData) (Nsf_Class *cl, ClientData data); /* 22 */
-    ClientData (*nsfGetClassClientData) (Nsf_Class *cl); /* 23 */
-    void (*nsfRequireObjNamespace) (Tcl_Interp *interp, Nsf_Object *obj); /* 24 */
-    int (*nsfErrBadVal) (Tcl_Interp *interp, char *context, char *expected, CONST char *value); /* 25 */
-    int (*nsfNextObjCmd) (ClientData cd, Tcl_Interp *interp, int objc, Tcl_Obj *CONST objv[]); /* 26 */
-    int (*nsfCallMethodWithArgs) (ClientData cd, Tcl_Interp *interp, Tcl_Obj *method, Tcl_Obj *arg, int objc, Tcl_Obj *CONST objv[], int flags); /* 27 */
-    int (*nsfObjErrArgCnt) (Tcl_Interp *interp, Tcl_Obj *cmdName, Tcl_Obj *methodName, char *arglist); /* 28 */
-    int (*nsfAddObjectMethod) (Tcl_Interp *interp, struct Nsf_Object *obj, CONST char *nm, Tcl_ObjCmdProc *proc, ClientData cd, Tcl_CmdDeleteProc *dp, int flags); /* 29 */
-    int (*nsfAddClassMethod) (Tcl_Interp *interp, struct Nsf_Class *cl, CONST char *nm, Tcl_ObjCmdProc *proc, ClientData cd, Tcl_CmdDeleteProc *dp, int flags); /* 30 */
-    int (*nsfCreate) (Tcl_Interp *in, Nsf_Class *class, Tcl_Obj *name, ClientData data, int objc, Tcl_Obj *CONST objv[]); /* 31 */
+    void (*nsfDStringPrintf) (Tcl_DString *dsPtr, CONST char *fmt, va_list apSrc); /* 16 */
+    int (*nsfErrInProc) (Tcl_Interp *interp, Tcl_Obj *objName, Tcl_Obj *clName, CONST char *procName); /* 17 */
+    int (*nsfErrBadVal_) (Tcl_Interp *interp, char *expected, char *value); /* 18 */
+    int (*nsfObjErrType) (Tcl_Interp *interp, Tcl_Obj *nm, char *wt, char *parameterName); /* 19 */
+    void (*nsfStackDump) (Tcl_Interp *interp); /* 20 */
+    void (*nsfSetObjClientData) (Nsf_Object *obj, ClientData data); /* 21 */
+    ClientData (*nsfGetObjClientData) (Nsf_Object *obj); /* 22 */
+    void (*nsfSetClassClientData) (Nsf_Class *cl, ClientData data); /* 23 */
+    ClientData (*nsfGetClassClientData) (Nsf_Class *cl); /* 24 */
+    void (*nsfRequireObjNamespace) (Tcl_Interp *interp, Nsf_Object *obj); /* 25 */
+    int (*nsfErrBadVal) (Tcl_Interp *interp, char *context, char *expected, CONST char *value); /* 26 */
+    int (*nsfNextObjCmd) (ClientData cd, Tcl_Interp *interp, int objc, Tcl_Obj *CONST objv[]); /* 27 */
+    int (*nsfCallMethodWithArgs) (ClientData cd, Tcl_Interp *interp, Tcl_Obj *method, Tcl_Obj *arg, int objc, Tcl_Obj *CONST objv[], int flags); /* 28 */
+    int (*nsfObjErrArgCnt) (Tcl_Interp *interp, Tcl_Obj *cmdName, Tcl_Obj *methodName, char *arglist); /* 29 */
+    int (*nsfAddObjectMethod) (Tcl_Interp *interp, struct Nsf_Object *obj, CONST char *nm, Tcl_ObjCmdProc *proc, ClientData cd, Tcl_CmdDeleteProc *dp, int flags); /* 30 */
+    int (*nsfAddClassMethod) (Tcl_Interp *interp, struct Nsf_Class *cl, CONST char *nm, Tcl_ObjCmdProc *proc, ClientData cd, Tcl_CmdDeleteProc *dp, int flags); /* 31 */
+    int (*nsfCreate) (Tcl_Interp *in, Nsf_Class *class, Tcl_Obj *name, ClientData data, int objc, Tcl_Obj *CONST objv[]); /* 32 */
 } NsfStubs;
 
 #ifdef __cplusplus
@@ -331,69 +338,73 @@
 #define NsfVarErrMsg \
 	(nsfStubsPtr->nsfVarErrMsg) /* 15 */
 #endif
+#ifndef NsfDStringPrintf
+#define NsfDStringPrintf \
+	(nsfStubsPtr->nsfDStringPrintf) /* 16 */
+#endif
 #ifndef NsfErrInProc
 #define NsfErrInProc \
-	(nsfStubsPtr->nsfErrInProc) /* 16 */
+	(nsfStubsPtr->nsfErrInProc) /* 17 */
 #endif
 #ifndef NsfErrBadVal_
 #define NsfErrBadVal_ \
-	(nsfStubsPtr->nsfErrBadVal_) /* 17 */
+	(nsfStubsPtr->nsfErrBadVal_) /* 18 */
 #endif
 #ifndef NsfObjErrType
 #define NsfObjErrType \
-	(nsfStubsPtr->nsfObjErrType) /* 18 */
+	(nsfStubsPtr->nsfObjErrType) /* 19 */
 #endif
 #ifndef NsfStackDump
 #define NsfStackDump \
-	(nsfStubsPtr->nsfStackDump) /* 19 */
+	(nsfStubsPtr->nsfStackDump) /* 20 */
 #endif
 #ifndef NsfSetObjClientData
 #define NsfSetObjClientData \
-	(nsfStubsPtr->nsfSetObjClientData) /* 20 */
+	(nsfStubsPtr->nsfSetObjClientData) /* 21 */
 #endif
 #ifndef NsfGetObjClientData
 #define NsfGetObjClientData \
-	(nsfStubsPtr->nsfGetObjClientData) /* 21 */
+	(nsfStubsPtr->nsfGetObjClientData) /* 22 */
 #endif
 #ifndef NsfSetClassClientData
 #define NsfSetClassClientData \
-	(nsfStubsPtr->nsfSetClassClientData) /* 22 */
+	(nsfStubsPtr->nsfSetClassClientData) /* 23 */
 #endif
 #ifndef NsfGetClassClientData
 #define NsfGetClassClientData \
-	(nsfStubsPtr->nsfGetClassClientData) /* 23 */
+	(nsfStubsPtr->nsfGetClassClientData) /* 24 */
 #endif
 #ifndef NsfRequireObjNamespace
 #define NsfRequireObjNamespace \
-	(nsfStubsPtr->nsfRequireObjNamespace) /* 24 */
+	(nsfStubsPtr->nsfRequireObjNamespace) /* 25 */
 #endif
 #ifndef NsfErrBadVal
 #define NsfErrBadVal \
-	(nsfStubsPtr->nsfErrBadVal) /* 25 */
+	(nsfStubsPtr->nsfErrBadVal) /* 26 */
 #endif
 #ifndef NsfNextObjCmd
 #define NsfNextObjCmd \
-	(nsfStubsPtr->nsfNextObjCmd) /* 26 */
+	(nsfStubsPtr->nsfNextObjCmd) /* 27 */
 #endif
 #ifndef NsfCallMethodWithArgs
 #define NsfCallMethodWithArgs \
-	(nsfStubsPtr->nsfCallMethodWithArgs) /* 27 */
+	(nsfStubsPtr->nsfCallMethodWithArgs) /* 28 */
 #endif
 #ifndef NsfObjErrArgCnt
 #define NsfObjErrArgCnt \
-	(nsfStubsPtr->nsfObjErrArgCnt) /* 28 */
+	(nsfStubsPtr->nsfObjErrArgCnt) /* 29 */
 #endif
 #ifndef NsfAddObjectMethod
 #define NsfAddObjectMethod \
-	(nsfStubsPtr->nsfAddObjectMethod) /* 29 */
+	(nsfStubsPtr->nsfAddObjectMethod) /* 30 */
 #endif
 #ifndef NsfAddClassMethod
 #define NsfAddClassMethod \
-	(nsfStubsPtr->nsfAddClassMethod) /* 30 */
+	(nsfStubsPtr->nsfAddClassMethod) /* 31 */
 #endif
 #ifndef NsfCreate
 #define NsfCreate \
-	(nsfStubsPtr->nsfCreate) /* 31 */
+	(nsfStubsPtr->nsfCreate) /* 32 */
 #endif
 
 #endif /* defined(USE_NSF_STUBS) && !defined(USE_NSF_STUB_PROCS) */
Index: generic/nsfError.c
===================================================================
diff -u -rcb7e3a02c1964d38d85c7e129027fc1b3225d3e6 -rf2c0f8e055015e58f3fa7bd338c872a2b7d76113
--- generic/nsfError.c	(.../nsfError.c)	(revision cb7e3a02c1964d38d85c7e129027fc1b3225d3e6)
+++ generic/nsfError.c	(.../nsfError.c)	(revision f2c0f8e055015e58f3fa7bd338c872a2b7d76113)
@@ -13,6 +13,39 @@
 
 #include "nsfInt.h"
 
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * NsfDStringPrintf --
+ *
+ *      Set a Tcl_DString to a formatted value. This function
+ *      currently copies at most TCL_DSTRING_STATIC_SIZE characters
+ *      into the DString (this limit might be lifted in the future)
+ *
+ * Results:
+ *      None.
+ *
+ * Side effects:
+ *      None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+NsfDStringPrintf(Tcl_DString *dsPtr, CONST char *fmt, va_list apSrc)
+{
+    int      result;
+    va_list  ap;
+
+    va_copy(ap, apSrc);
+    result = vsnprintf(Tcl_DStringValue(dsPtr), TCL_DSTRING_STATIC_SIZE, fmt, ap);
+    va_end(ap);
+
+    Tcl_DStringSetLength(dsPtr, result < TCL_DSTRING_STATIC_SIZE ? result : TCL_DSTRING_STATIC_SIZE);
+}
+
+
 int
 NsfErrMsg(Tcl_Interp *interp, char *msg, Tcl_FreeProc* type) {
     Tcl_SetResult(interp, msg, type);
Index: generic/nsfInt.h
===================================================================
diff -u -r2767762e5ef68bee6e82cbff0d69f54b01c37a13 -rf2c0f8e055015e58f3fa7bd338c872a2b7d76113
--- generic/nsfInt.h	(.../nsfInt.h)	(revision 2767762e5ef68bee6e82cbff0d69f54b01c37a13)
+++ generic/nsfInt.h	(.../nsfInt.h)	(revision f2c0f8e055015e58f3fa7bd338c872a2b7d76113)
@@ -840,6 +840,9 @@
 #define FRAME_IS_NSF_METHOD  0x20000
 #define FRAME_IS_NSF_CMETHOD 0x40000
 
+#define NSF_LOG_INFORM 2
+#define NSF_LOG_WARN 1
+
 #if !defined(NDEBUG)
 /*# define NSF_INLINE*/
 #endif
Index: generic/nsfStubInit.c
===================================================================
diff -u -r14965323980c2235c37b67ddbb19343ddbdaa41c -rf2c0f8e055015e58f3fa7bd338c872a2b7d76113
--- generic/nsfStubInit.c	(.../nsfStubInit.c)	(revision 14965323980c2235c37b67ddbb19343ddbdaa41c)
+++ generic/nsfStubInit.c	(.../nsfStubInit.c)	(revision f2c0f8e055015e58f3fa7bd338c872a2b7d76113)
@@ -52,22 +52,23 @@
     NsfUnsetInstVar2, /* 13 */
     NsfErrMsg, /* 14 */
     NsfVarErrMsg, /* 15 */
-    NsfErrInProc, /* 16 */
-    NsfErrBadVal_, /* 17 */
-    NsfObjErrType, /* 18 */
-    NsfStackDump, /* 19 */
-    NsfSetObjClientData, /* 20 */
-    NsfGetObjClientData, /* 21 */
-    NsfSetClassClientData, /* 22 */
-    NsfGetClassClientData, /* 23 */
-    NsfRequireObjNamespace, /* 24 */
-    NsfErrBadVal, /* 25 */
-    NsfNextObjCmd, /* 26 */
-    NsfCallMethodWithArgs, /* 27 */
-    NsfObjErrArgCnt, /* 28 */
-    NsfAddObjectMethod, /* 29 */
-    NsfAddClassMethod, /* 30 */
-    NsfCreate, /* 31 */
+    NsfDStringPrintf, /* 16 */
+    NsfErrInProc, /* 17 */
+    NsfErrBadVal_, /* 18 */
+    NsfObjErrType, /* 19 */
+    NsfStackDump, /* 20 */
+    NsfSetObjClientData, /* 21 */
+    NsfGetObjClientData, /* 22 */
+    NsfSetClassClientData, /* 23 */
+    NsfGetClassClientData, /* 24 */
+    NsfRequireObjNamespace, /* 25 */
+    NsfErrBadVal, /* 26 */
+    NsfNextObjCmd, /* 27 */
+    NsfCallMethodWithArgs, /* 28 */
+    NsfObjErrArgCnt, /* 29 */
+    NsfAddObjectMethod, /* 30 */
+    NsfAddClassMethod, /* 31 */
+    NsfCreate, /* 32 */
 };
 
 /* !END!: Do not edit above this line. */
Index: generic/predefined.h
===================================================================
diff -u -r6c2e8f94be1ba335ff90d4b6b5132c98a9f5c242 -rf2c0f8e055015e58f3fa7bd338c872a2b7d76113
--- generic/predefined.h	(.../predefined.h)	(revision 6c2e8f94be1ba335ff90d4b6b5132c98a9f5c242)
+++ generic/predefined.h	(.../predefined.h)	(revision f2c0f8e055015e58f3fa7bd338c872a2b7d76113)
@@ -33,6 +33,11 @@
 "unset {proc ::nsf::__exithandler args {;}}\n"
 "default {error \"syntax: ::nsf::exithandler $::nsf::parametersyntax(::nsf::exithandler)\"}}}\n"
 "::nsf::exithandler unset\n"
+"if {[info command ::ns_log] ne \"\"} {\n"
+"proc ::nsf::log {level msg} {\n"
+"ns_log $level \"nsf: $msg\"}} else {\n"
+"proc ::nsf::log {level msg} {\n"
+"puts stderr \"$level: $msg\"}}\n"
 "proc tmpdir {} {\n"
 "foreach e [list TMPDIR TEMP TMP] {\n"
 "if {[info exists ::env($e)] \\\n"