--- a/QuerySignal.st Thu May 09 15:24:26 1996 +0200
+++ b/QuerySignal.st Thu May 09 15:24:48 1996 +0200
@@ -41,9 +41,13 @@
signal. Thus, these bypass anySignal handlers.
If unhandled, no error is raised, instead they are simply ignored
(as opposed to normal signals, which raise an unhandled signal exception).
+ QuerySignals are also ignored, if a handler exists, but rejects.
- Their main use is to implement up-Queries via signals even if intermediate
- errorSignal handlers are present (which is not possible with ordinary signals).
+ Their main use is to implement up-Queries via signals, that work even
+ if intermediate errorSignal handlers are present
+ (which is not possible with ordinary signals, since errorSignal handlers
+ would catch those signals).
+
Code deep down in the calling hierarchy can post such an up-Query to ask
for some information in return or to pass some information upward.
@@ -58,6 +62,7 @@
[see also:]
Signal SignalSet Exception
Object
+ (``Exception handling and signals'': programming/exceptions.html)
[author:]
Claus Gittinger
@@ -126,5 +131,5 @@
!QuerySignal class methodsFor:'documentation'!
version
- ^ '$Header: /cvs/stx/stx/libbasic/QuerySignal.st,v 1.10 1996-04-27 18:00:44 cg Exp $'
+ ^ '$Header: /cvs/stx/stx/libbasic/QuerySignal.st,v 1.11 1996-05-09 13:23:57 cg Exp $'
! !