CVS difference for ais/ai-00166.txt

Differences between 1.1 and version 1.2
Log of other versions for file ais/ai-00166.txt

--- ais/ai-00166.txt	1998/09/30 00:17:31	1.1
+++ ais/ai-00166.txt	1998/10/01 00:24:28	1.2
@@ -1,4 +1,4 @@
-!standard C.3.2    (18)                               98-05-06  AI95-00166/01
+!standard C.3.2    (18)                               98-05-06  AI95-00166/02
 !class binding interpretation 96-11-16
 !status work item (draft by Ted Baker, per action at St. Louis meeting)
 !status received 96-11-16
@@ -233,7 +233,7 @@
 a given interrupt, as explained below.  C.3.2(17) states that a null
 value for the New_Handler parameter of Attach_Handler (and, as a
 consequence of C.3.2(18), of Exchange_Handler) specifies restoration of
-the default treament; but this does not mean that null is the ONLY
+the default treatment; but this does not mean that null is the ONLY
 Parameterless_Handler value specifying the default treatment.
 
 On the other hand, since the default treatment in effect when a program
@@ -360,7 +360,7 @@
 
 The intent was to allow something like the UNIX sigaction()
 interface, which uses certain "special" values that are not
-themselves procedure pointers, to indicate speical treatments
+themselves procedure pointers, to indicate special treatments
 (namely, the default treatment and to ignore the signal).
 
 For example, the value -1 might be reserved to indicate
@@ -396,7 +396,7 @@
 >
 > The intent was to allow something like the UNIX sigaction()
 > interface, which uses certain "special" values that are not
-> themselves procedure pointers, to indicate speical treatments
+> themselves procedure pointers, to indicate special treatments
 > (namely, the default treatment and to ignore the signal).
 >
 > For example, the value -1 might be reserved to indicate
@@ -446,7 +446,7 @@
 
 | > The intent was to allow something like the UNIX sigaction()
 | > interface, which uses certain "special" values that are not
-| > themselves procedure pointers, to indicate speical treatments
+| > themselves procedure pointers, to indicate special treatments
 | > (namely, the default treatment and to ignore the signal).
 
 | Since "null" is used to indicate a default treatment elsewhere
@@ -505,7 +505,7 @@
 
 > | > The intent was to allow something like the UNIX sigaction()
 > | > interface, which uses certain "special" values that are not
-> | > themselves procedure pointers, to indicate speical treatments
+> | > themselves procedure pointers, to indicate special treatments
 > | > (namely, the default treatment and to ignore the signal).
 >
 > | Since "null" is used to indicate a default treatment elsewhere
@@ -698,3 +698,50 @@
 --Ted Baker
 
 ****************************************************************
+
+From the minutes of the Henley meeting:
+
+AI-166 Parameterless_Handler values designating default treatment
+
+What is this AI saying?
+
+Apparently Norm wants to tighten the semantics for the default handler.  
+This is counter to the principle of leaving the semantics vague to permit 
+implementation flexibility, especially on existing operating systems.  Ted 
+complicates the situation by pointing out that an operating system can 
+change the default treatment.
+
+Also, there are some style changes, namely the use of treatment and handler 
+that is causing confusion; Bob indicates that treatment was added to permit 
+the ability of the default to change (by the OS).
+
+Erhard summarizes the alternatives (and prefers no. 1):
+1. Current and old handler is null for default treatment; this was modified 
+by Ted to "for any non-user-provided handler/treatment"
+2. Current and old handler is not null and callable (by X.all)
+3. Current and old handler is not null and may be callable if it is user-
+defined handler and not callable if it is default handler/treatment
+
+Bob states that the current statement of the RM permits either 1 or 3 as 
+defined by the implementation.
+
+Erhard asks for vote, late in the first day, on Alternative 1: 6-3
+
+On the next  day:
+
+Ted convinced himself by the name "Exchange Handler" that the
+focus of this operation is handler and not treatments; so that
+default treatment is expressed by null for the purposes of the Ada
+application and for later exchange (restoration).
+
+The only remaining issue is the possibility of changing the
+default treatment from the underlying OS.  After some discussion
+of the terms "current", "default" and "current default", it was
+decided to stick with "default" with comments that the OS
+implementation may change the value of default treatment; "current
+default" would only encourage such behavior.
+
+Erhard asks for a revote on Alternative 1:  9-0-0
+
+****************************************************************
+

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