--- a/ExternalAddress.st	Wed Aug 04 18:03:48 2004 +0200
+++ b/ExternalAddress.st	Thu Aug 05 13:48:43 2004 +0200
@@ -39,29 +39,30 @@
 "
     Instances of this class represent external (non-Smalltalk) addresses.
     They are only useful to represent handles as returned by C functions
-    as smalltalk objects. For example, Window- or WidgetIDs (which are actually
-    32 bit pointers) should be represented this way.
+    as smalltalk objects. 
+    For example, Window- or WidgetIDs (which are actually 32 bit pointers) could be represented this way
+    (better create a handle-subclass for it, to care for proper finalization).
     (you should not use SmallIntegers for this, since they can only represent 31
      bits; LargeIntegers could be used in theory, but it is not a very good style
      to do so, since it makes things a bit cryptic - having ExternalAddresses
      around makes things pretty clear in inspectors etc.).
 
     There is not much you can do with ExternalAddresses on the smalltalk level;
-    creation/use is mostly in primitive C-code via 
+    creation/use should be done in primitive C-code via 
        __MKEXTERNALADDRESS(voidPtr) and __ExternalAddressVal(obj).
 
     ExternallAddresses are much like ExternalBytes - however, the latter
     allow you to access bytes via indexed at:/at:put: messages.
-    ExternalAddresses do not allow such accesses (they are meant to remain
-    anonymous).
+    ExternalAddresses do not allow such accesses (they are meant to remain anonymous, opaque handles).
+    Also, memory blocks which are freeable should be represented as ExternalBytes.
 
     [author:]
-	Claus Gittinger
+        Claus Gittinger
 
     [see also:]
-	ByteArray
-	ExternalBytes ExternalFunction
-	( how to write primitive code :html: programming/primitive.html )
+        ByteArray
+        ExternalBytes ExternalFunction
+        ( how to write primitive code :html: programming/primitive.html )
 "
 !
 
@@ -128,6 +129,12 @@
     "
 ! !
 
+!ExternalAddress methodsFor:'Compatibility-Squeak'!
+
+beNull
+    self setAddress:0
+! !
+
 !ExternalAddress methodsFor:'accessing'!
 
 address
@@ -278,5 +285,5 @@
 !ExternalAddress class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libbasic/ExternalAddress.st,v 1.18 2003-05-07 14:10:07 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic/ExternalAddress.st,v 1.19 2004-08-05 11:48:43 cg Exp $'
 ! !