From 01ccc13fce6a0fb9e8cd19a5b5697da62feb1750 Mon Sep 17 00:00:00 2001
From: keithw <unknown>
Date: Mon, 29 Mar 1999 14:09:36 +0000
Subject: [PATCH] [project @ 1999-03-29 14:09:36 by keithw] Useful comment
 added. (this is really a CVS checkin test, please
 ignore...)  --keithw

---
 ghc/compiler/stgSyn/StgSyn.lhs |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/ghc/compiler/stgSyn/StgSyn.lhs b/ghc/compiler/stgSyn/StgSyn.lhs
index 4e8ab45..1f67634 100644
--- a/ghc/compiler/stgSyn/StgSyn.lhs
+++ b/ghc/compiler/stgSyn/StgSyn.lhs
@@ -445,6 +445,12 @@ type StgCaseDefault = GenStgCaseDefault	Id Id
 
 This is also used in @LambdaFormInfo@ in the @ClosureInfo@ module.
 
+A @ReEntrant@ closure may be entered multiple times, but should not be
+updated or blackholed.  An @Updatable@ closure should be updated after
+evaluation (and may be blackholed during evaluation).  A @SingleEntry@
+closure will only be entered once, and so need not be updated but may
+safely be blackholed.
+
 \begin{code}
 data UpdateFlag = ReEntrant | Updatable | SingleEntry
 
-- 
1.7.10.4