diff --git a/src/remoteClient/clientContextImpl.cpp b/src/remoteClient/clientContextImpl.cpp
index 1edad7d..4031504 100644
--- a/src/remoteClient/clientContextImpl.cpp
+++ b/src/remoteClient/clientContextImpl.cpp
@@ -134,6 +134,8 @@ protected:
 
     pvAccessID m_ioid;
 
+    // holds: NULL_REQUEST, PURE_DESTROY_REQUEST, PURE_CANCEL_REQUEST, or
+    // a mask of QOS_*
     int32 m_pendingRequest;
 
     Mutex m_mutex;
@@ -221,22 +223,29 @@ protected:
     bool startRequest(int32 qos) {
         Lock guard(m_mutex);
 
-        // we allow pure destroy...
-        if (m_pendingRequest != NULL_REQUEST && qos != PURE_DESTROY_REQUEST && qos != PURE_CANCEL_REQUEST)
-            return false;
+        if(qos==PURE_DESTROY_REQUEST)
+        {/* always allow destroy */}
+        else if(qos==PURE_CANCEL_REQUEST && m_pendingRequest!=PURE_DESTROY_REQUEST)
+        {/* cancel overrides all but destroy */}
+        else if(m_pendingRequest==NULL_REQUEST)
+        {/* anything whenidle */}
+        else
+        {return false; /* others not allowed */}
 
         m_pendingRequest = qos;
         return true;
     }
 
-    void stopRequest() {
+    int32 beginRequest() {
         Lock guard(m_mutex);
+        int32 ret = m_pendingRequest;
         m_pendingRequest = NULL_REQUEST;
+        return ret;
     }
 
-    int32 getPendingRequest() {
+    void abortRequest() {
         Lock guard(m_mutex);
-        return m_pendingRequest;
+        m_pendingRequest = NULL_REQUEST;
     }
 
 public:
@@ -369,7 +378,7 @@ public:
         else if (status == Channel::DISCONNECTED)
         {
             m_subscribed.clear();
-            stopRequest();
+            abortRequest();
         }
         // TODO notify?
     }
@@ -384,10 +393,11 @@ public:
 
     void updateSubscription() {}
 
-    virtual void send(ByteBuffer* buffer, TransportSendControl* control) OVERRIDE {
-        int8 qos = getPendingRequest();
-        if (qos == -1)
+    // sub-class send() calls me
+    void base_send(ByteBuffer* buffer, TransportSendControl* control, int8 qos) {
+        if (qos == NULL_REQUEST) {
             return;
+        }
         else if (qos == PURE_DESTROY_REQUEST)
         {
             control->startMessage((int8)CMD_DESTROY_REQUEST, 8);
@@ -400,7 +410,6 @@ public:
             buffer->putInt(m_channel->getServerChannelID());
             buffer->putInt(m_ioid);
         }
-        stopRequest();
     }
 
 };
@@ -460,10 +469,10 @@ public:
     ChannelBaseRequester::shared_pointer getRequester() OVERRIDE FINAL { return m_callback.lock(); }
 
     virtual void send(ByteBuffer* buffer, TransportSendControl* control) OVERRIDE FINAL {
-        int32 pendingRequest = getPendingRequest();
+        int32 pendingRequest = beginRequest();
         if (pendingRequest < 0)
         {
-            BaseRequestImpl::send(buffer, control);
+            base_send(buffer, control, pendingRequest);
             return;
         }
 
@@ -477,8 +486,6 @@ public:
             // pvRequest
             SerializationHelper::serializePVRequest(buffer, control, m_pvRequest);
         }
-
-        stopRequest();
     }
 
     virtual void initResponse(Transport::shared_pointer const & /*transport*/, int8 /*version*/, ByteBuffer* /*payloadBuffer*/, int8 /*qos*/, const Status& status) OVERRIDE FINAL {
@@ -513,7 +520,7 @@ public:
         try {
             m_channel->checkAndGetTransport()->enqueueSendRequest(internal_from_this<BaseRequestImpl>());
         } catch (std::runtime_error &rte) {
-            stopRequest();
+            abortRequest();
             EXCEPTION_GUARD3(m_callback, cb, cb->processDone(channelNotConnected, thisPtr));
         }
     }
@@ -597,12 +604,12 @@ public:
     ChannelBaseRequester::shared_pointer getRequester() OVERRIDE FINAL { return m_callback.lock(); }
 
     virtual void send(ByteBuffer* buffer, TransportSendControl* control) OVERRIDE FINAL {
-        int32 pendingRequest = getPendingRequest();
+        int32 pendingRequest = beginRequest();
         bool initStage = ((pendingRequest & QOS_INIT) != 0);
 
         if (pendingRequest < 0)
         {
-            BaseRequestImpl::send(buffer, control);
+            base_send(buffer, control, pendingRequest);
             return;
         }
 
@@ -616,8 +623,6 @@ public:
             // pvRequest
             SerializationHelper::serializePVRequest(buffer, control, m_pvRequest);
         }
-
-        stopRequest();
     }
 
     virtual void initResponse(Transport::shared_pointer const & transport, int8 /*version*/, ByteBuffer* payloadBuffer, int8 /*qos*/, const Status& status) OVERRIDE FINAL {
@@ -678,7 +683,7 @@ public:
                         try {
                             m_channel->checkAndGetTransport()->flushSendQueue();
                         } catch (std::runtime_error &rte) {
-                            stopRequest();
+                            abortRequest();
                             EXCEPTION_GUARD3(m_callback, cb, cb->getDone(channelNotConnected, thisPtr));
                         }
                         return;
@@ -693,7 +698,7 @@ public:
             m_channel->checkAndGetTransport()->enqueueSendRequest(internal_from_this<ChannelGetImpl>());
             //TODO bulk hack m_channel->checkAndGetTransport()->enqueueOnlySendRequest(thisSender);
         } catch (std::runtime_error &rte) {
-            stopRequest();
+            abortRequest();
             EXCEPTION_GUARD3(m_callback, cb, cb->getDone(channelNotConnected, thisPtr, PVStructurePtr(), BitSetPtr()));
         }
     }
@@ -787,10 +792,10 @@ public:
     ChannelBaseRequester::shared_pointer getRequester() OVERRIDE FINAL { return m_callback.lock(); }
 
     virtual void send(ByteBuffer* buffer, TransportSendControl* control) OVERRIDE FINAL {
-        int32 pendingRequest = getPendingRequest();
+        int32 pendingRequest = beginRequest();
         if (pendingRequest < 0)
         {
-            BaseRequestImpl::send(buffer, control);
+            base_send(buffer, control, pendingRequest);
             return;
         }
 
@@ -815,8 +820,6 @@ public:
                 m_structure->serialize(buffer, control, m_bitSet.get());
             }
         }
-
-        stopRequest();
     }
 
     virtual void initResponse(Transport::shared_pointer const & transport, int8 /*version*/, ByteBuffer* payloadBuffer, int8 /*qos*/, const Status& status) OVERRIDE FINAL {
@@ -888,7 +891,7 @@ public:
         try {
             m_channel->checkAndGetTransport()->enqueueSendRequest(internal_from_this<ChannelPutImpl>());
         } catch (std::runtime_error &rte) {
-            stopRequest();
+            abortRequest();
             EXCEPTION_GUARD3(m_callback, cb, cb->getDone(channelNotConnected, thisPtr, PVStructurePtr(), BitSetPtr()));
         }
     }
@@ -933,7 +936,7 @@ public:
             unlock();
             m_channel->checkAndGetTransport()->enqueueSendRequest(internal_from_this<ChannelPutImpl>());
         } catch (std::runtime_error &rte) {
-            stopRequest();
+            abortRequest();
             EXCEPTION_GUARD3(m_callback, cb, cb->putDone(channelNotConnected, thisPtr));
         }
     }
@@ -1030,10 +1033,10 @@ public:
     ChannelBaseRequester::shared_pointer getRequester() OVERRIDE FINAL { return m_callback.lock(); }
 
     virtual void send(ByteBuffer* buffer, TransportSendControl* control) OVERRIDE FINAL {
-        int32 pendingRequest = getPendingRequest();
+        int32 pendingRequest = beginRequest();
         if (pendingRequest < 0)
         {
-            BaseRequestImpl::send(buffer, control);
+            base_send(buffer, control, pendingRequest);
             return;
         }
 
@@ -1062,8 +1065,6 @@ public:
                 m_putData->serialize(buffer, control, m_putDataBitSet.get());
             }
         }
-
-        stopRequest();
     }
 
     virtual void initResponse(Transport::shared_pointer const & transport, int8 /*version*/, ByteBuffer* payloadBuffer, int8 /*qos*/, const Status& status) OVERRIDE FINAL {
@@ -1184,7 +1185,7 @@ public:
             unlock();
             m_channel->checkAndGetTransport()->enqueueSendRequest(internal_from_this<ChannelPutGetImpl>());
         } catch (std::runtime_error &rte) {
-            stopRequest();
+            abortRequest();
             EXCEPTION_GUARD3(m_callback, cb, cb->putGetDone(channelNotConnected, thisPtr, PVStructurePtr(), BitSetPtr()));
         }
     }
@@ -1213,7 +1214,7 @@ public:
         try {
             m_channel->checkAndGetTransport()->enqueueSendRequest(internal_from_this<ChannelPutGetImpl>());
         } catch (std::runtime_error &rte) {
-            stopRequest();
+            abortRequest();
             EXCEPTION_GUARD3(m_callback, cb, cb->getGetDone(channelNotConnected, thisPtr, PVStructurePtr(), BitSetPtr()));
         }
     }
@@ -1242,7 +1243,7 @@ public:
         try {
             m_channel->checkAndGetTransport()->enqueueSendRequest(internal_from_this<ChannelPutGetImpl>());
         } catch (std::runtime_error &rte) {
-            stopRequest();
+            abortRequest();
             EXCEPTION_GUARD3(m_callback, cb, cb->getPutDone(channelNotConnected, thisPtr, PVStructurePtr(), BitSetPtr()));
         }
     }
@@ -1336,10 +1337,10 @@ public:
     ChannelBaseRequester::shared_pointer getRequester() OVERRIDE FINAL { return m_callback.lock(); }
 
     virtual void send(ByteBuffer* buffer, TransportSendControl* control) OVERRIDE FINAL {
-        int32 pendingRequest = getPendingRequest();
+        int32 pendingRequest = beginRequest();
         if (pendingRequest < 0)
         {
-            BaseRequestImpl::send(buffer, control);
+            base_send(buffer, control, pendingRequest);
             return;
         }
 
@@ -1366,8 +1367,6 @@ public:
                 m_structure.reset();
             }
         }
-
-        stopRequest();
     }
 
     virtual void initResponse(Transport::shared_pointer const & /*transport*/, int8 /*version*/, ByteBuffer* /*payloadBuffer*/, int8 /*qos*/, const Status& status) OVERRIDE FINAL {
@@ -1424,7 +1423,7 @@ public:
 
             m_channel->checkAndGetTransport()->enqueueSendRequest(internal_from_this<ChannelRPCImpl>());
         } catch (std::runtime_error &rte) {
-            stopRequest();
+            abortRequest();
             EXCEPTION_GUARD3(m_callback, cb, cb->requestDone(channelNotConnected, thisPtr, PVStructurePtr()));
         }
     }
@@ -1525,10 +1524,10 @@ public:
     ChannelBaseRequester::shared_pointer getRequester() OVERRIDE FINAL { return m_callback.lock(); }
 
     virtual void send(ByteBuffer* buffer, TransportSendControl* control) OVERRIDE FINAL {
-        int32 pendingRequest = getPendingRequest();
+        int32 pendingRequest = beginRequest();
         if (pendingRequest < 0)
         {
-            BaseRequestImpl::send(buffer, control);
+            base_send(buffer, control, pendingRequest);
             return;
         }
 
@@ -1570,8 +1569,6 @@ public:
                 m_arrayData->serialize(buffer, control, 0, m_count ? m_count : m_arrayData->getLength()); // put from 0 offset (see API doc), m_count == 0 means entire array
             }
         }
-
-        stopRequest();
     }
 
     virtual void initResponse(Transport::shared_pointer const & transport, int8 /*version*/, ByteBuffer* payloadBuffer, int8 /*qos*/, const Status& status) OVERRIDE FINAL {
@@ -1660,7 +1657,7 @@ public:
             }
             m_channel->checkAndGetTransport()->enqueueSendRequest(internal_from_this<ChannelArrayImpl>());
         } catch (std::runtime_error &rte) {
-            stopRequest();
+            abortRequest();
             EXCEPTION_GUARD3(m_callback, cb, cb->getArrayDone(channelNotConnected, thisPtr, PVArray::shared_pointer()));
         }
     }
@@ -1704,7 +1701,7 @@ public:
             }
             m_channel->checkAndGetTransport()->enqueueSendRequest(internal_from_this<ChannelArrayImpl>());
         } catch (std::runtime_error &rte) {
-            stopRequest();
+            abortRequest();
             EXCEPTION_GUARD3(m_callback, cb, cb->putArrayDone(channelNotConnected, thisPtr));
         }
     }
@@ -1737,7 +1734,7 @@ public:
             }
             m_channel->checkAndGetTransport()->enqueueSendRequest(internal_from_this<ChannelArrayImpl>());
         } catch (std::runtime_error &rte) {
-            stopRequest();
+            abortRequest();
             EXCEPTION_GUARD3(m_callback, cb, cb->setLengthDone(channelNotConnected, thisPtr));
         }
     }
@@ -1767,7 +1764,7 @@ public:
         try {
             m_channel->checkAndGetTransport()->enqueueSendRequest(internal_from_this<ChannelArrayImpl>());
         } catch (std::runtime_error &rte) {
-            stopRequest();
+            abortRequest();
             EXCEPTION_GUARD3(m_callback, cb, cb->getLengthDone(channelNotConnected, thisPtr, 0));
         }
     }
@@ -2231,10 +2228,10 @@ public:
     ChannelBaseRequester::shared_pointer getRequester() OVERRIDE FINAL { return m_callback.lock(); }
 
     virtual void send(ByteBuffer* buffer, TransportSendControl* control) OVERRIDE FINAL {
-        int32 pendingRequest = getPendingRequest();
+        int32 pendingRequest = beginRequest();
         if (pendingRequest < 0)
         {
-            BaseRequestImpl::send(buffer, control);
+            base_send(buffer, control, pendingRequest);
             return;
         }
 
@@ -2255,8 +2252,6 @@ public:
                 buffer->putInt(m_queueSize);
             }
         }
-
-        stopRequest();
     }
 
     virtual void initResponse(
@@ -2373,7 +2368,7 @@ public:
             m_started = true;
             return Status::Ok;
         } catch (std::runtime_error &rte) {
-            stopRequest();
+            abortRequest();
             return BaseRequestImpl::channelNotConnected;
         }
     }
@@ -2399,7 +2394,7 @@ public:
             m_started = false;
             return Status::Ok;
         } catch (std::runtime_error &rte) {
-            stopRequest();
+            abortRequest();
             return BaseRequestImpl::channelNotConnected;
         }
     }