From 24e83daaba1c7b3618b355b4f4dc37ab79414a74 Mon Sep 17 00:00:00 2001
From: Michael Davidsaver <mdavidsaver@gmail.com>
Date: Wed, 11 Sep 2019 18:03:39 -0700
Subject: [PATCH] pvac::Monitor::cancel() don't clear data members

Clearing root, overrun, and changed makes it difficult
to avoid a race during an async. cancel (very common).
---
 src/client/clientMonitor.cpp | 3 ---
 src/client/pva/client.h      | 6 +++++-
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/client/clientMonitor.cpp b/src/client/clientMonitor.cpp
index 55f6b9c..90113e4 100644
--- a/src/client/clientMonitor.cpp
+++ b/src/client/clientMonitor.cpp
@@ -196,9 +196,6 @@ std::string Monitor::name() const
 
 void Monitor::cancel()
 {
-    changed.clear();
-    overrun.clear();
-    root.reset();
     if(impl) impl->cancel();
 }
 
diff --git a/src/client/pva/client.h b/src/client/pva/client.h
index 9578fb4..446ca11 100644
--- a/src/client/pva/client.h
+++ b/src/client/pva/client.h
@@ -124,7 +124,11 @@ struct epicsShareClass Monitor
     //! Channel name
     std::string name() const;
     //! Immediate cancellation.
-    //! Does not wait for remote confirmation.
+    /** Does not wait for remote confirmation.
+     *
+     @since Up to 7.0.0 also cleared root, changed, and overrun.
+            After 7.0.0, these data members are left unchanged.
+     **/
     void cancel();
     /** updates root, changed, overrun
      *