added aux thread to call ca_clear_subscription

src/ca/stopMonitorThread.h

@@ -0,0 +1,56 @@
+/**
+ * Copyright - See the COPYRIGHT that is included with this distribution.
+ * pvAccessCPP is distributed subject to a Software License Agreement found
+ * in file LICENSE that is included with this distribution.
+ */
+/**
+ * @author mrk
+ * @date 2018.04
+ */
+#ifndef StopMonitorThread_H
+#define StopMonitorThread_H
+#include <queue>
+#include <cadef.h>
+#include <shareLib.h>
+#include <epicsThread.h>
+#include <pv/event.h>
+#include <pv/lock.h>
+
+namespace epics {
+namespace pvAccess {
+namespace ca {
+
+class StopMonitorThread;
+typedef std::tr1::shared_ptr<StopMonitorThread> StopMonitorThreadPtr;
+
+class StopMonitorThread :
+     public epicsThreadRunable
+{
+public:
+    ~StopMonitorThread();
+    virtual void run();
+    void start();
+    void stop();
+    static StopMonitorThreadPtr get();
+    void callStop(evid pevid);
+    void attachContext(ca_client_context* current_context);
+    void waitForNoEvents();
+private:
+    StopMonitorThread();
+
+    std::tr1::shared_ptr<epicsThread> thread;
+    epics::pvData::Mutex mutex;
+    epics::pvData::Event waitForCommand;
+    epics::pvData::Event waitForStop;
+    epics::pvData::Event noMoreEvents;
+    std::queue<evid> evidQueue;
+    bool isStop;
+    bool isAttachContext;
+    bool isWaitForNoEvents;
+    ca_client_context* current_context;
+};
+
+
+}}}
+
+#endif  /* StopMonitorThread_H */