Make attach* functions return bool in multi-channel types

The attachAlarm and attachTimeStamps() return true if successful, false
otherwise in other classes. In NTMultiChannel and NTScalarMultiChannel
they returned void. Bring multi-channel behaviour in line.

src/nt/ntmultiChannel.cpp

@@ -278,16 +278,20 @@ NTMultiChannel::NTMultiChannel(PVStructurePtr const & pvStructure)
 }
 
 
-void  NTMultiChannel::attachTimeStamp(PVTimeStamp &pv) const
+bool  NTMultiChannel::attachTimeStamp(PVTimeStamp &pv) const
 {
-    if(!pvTimeStamp) return;
-    pv.attach(pvTimeStamp);
+    if (pvTimeStamp)
+        return pv.attach(pvTimeStamp);
+    else
+        return false;
 }
 
-void  NTMultiChannel::attachAlarm(PVAlarm &pv) const
+bool  NTMultiChannel::attachAlarm(PVAlarm &pv) const
 {
-    if(!pvAlarm) return;
-    pv.attach(pvAlarm);
+    if (pvAlarm)
+        return pv.attach(pvAlarm);
+    else
+        return false;
 }
 
 }}

src/nt/ntmultiChannel.h

@@ -212,18 +212,21 @@ public:
      * Destructor
      */
     ~NTMultiChannel() {}
-     /**
-      * Attach a pvTimeStamp.
-      * @param pvTimeStamp The pvTimeStamp that will be attached.
-      * Does nothing if no timeStamp
-      */
-    void attachTimeStamp(epics::pvData::PVTimeStamp &pvTimeStamp) const;
+    /**
+     * Attach a pvTimeStamp.
+     * @param pvTimeStamp The pvTimeStamp that will be attached.
+     * Does nothing if no timeStamp.
+     * @return true if the operation was successfull (i.e. this instance
+has a timeStamp field), otherwise false.
+     */
+    bool attachTimeStamp(epics::pvData::PVTimeStamp &pvTimeStamp) const;
     /**
      * Attach a pvAlarm.
      * @param pvAlarm The pvAlarm that will be attached.
-     * Does nothing if no alarm
+     * Does nothing if no alarm.
+     * @return true if the operation was successfull (i.e. this instance has a timeStamp field), otherwise false.
      */
-    void attachAlarm(epics::pvData::PVAlarm &pvAlarm) const;
+    bool attachAlarm(epics::pvData::PVAlarm &pvAlarm) const;
     /**
      * Get the pvStructure.
      * @return PVStructurePtr.

src/nt/ntscalarMultiChannel.cpp

@@ -275,16 +275,20 @@ NTScalarMultiChannel::NTScalarMultiChannel(PVStructurePtr const & pvStructure)
 }
 
 
-void  NTScalarMultiChannel::attachTimeStamp(PVTimeStamp &pv) const
+bool  NTScalarMultiChannel::attachTimeStamp(PVTimeStamp &pv) const
 {
-    if(!pvTimeStamp) return;
-    pv.attach(pvTimeStamp);
+    if (pvTimeStamp)
+        return pv.attach(pvTimeStamp);
+    else
+        return false;
 }
 
-void  NTScalarMultiChannel::attachAlarm(PVAlarm &pv) const
+bool  NTScalarMultiChannel::attachAlarm(PVAlarm &pv) const
 {
-    if(!pvAlarm) return;
-    pv.attach(pvAlarm);
+    if (pvAlarm)
+        return pv.attach(pvAlarm);
+    else
+        return false;
 }
 
 }}

src/nt/ntscalarMultiChannel.h

@@ -213,18 +213,20 @@ public:
      * Destructor
      */
     ~NTScalarMultiChannel() {}
-     /**
-      * Attach a pvTimeStamp.
-      * @param pvTimeStamp The pvTimeStamp that will be attached.
-      * Does nothing if no timeStamp
-      */
-    void attachTimeStamp(epics::pvData::PVTimeStamp &pvTimeStamp) const;
+    /**
+     * Attach a pvTimeStamp.
+     * @param pvTimeStamp The pvTimeStamp that will be attached.
+     * Does nothing if no timeStamp.
+     * @return true if the operation was successfull (i.e. this instance has a timeStamp field), otherwise false.
+     */
+    bool attachTimeStamp(epics::pvData::PVTimeStamp &pvTimeStamp) const;
     /**
      * Attach a pvAlarm.
      * @param pvAlarm The pvAlarm that will be attached.
-     * Does nothing if no alarm
+     * Does nothing if no alarm.
+     * @return true if the operation was successfull (i.e. this instance has a timeStamp field), otherwise false.
      */
-    void attachAlarm(epics::pvData::PVAlarm &pvAlarm) const;
+    bool attachAlarm(epics::pvData::PVAlarm &pvAlarm) const;
     /**
      * Get the pvStructure.
      * @return PVStructurePtr.