added try/catch blocks so that we hopefully can bridge

periods where the new general time provides (unexpectedly
considering its advertised benfits) no time at all.

src/libCom/timer/epicsTimer.cpp

@@ -173,7 +173,12 @@ extern "C" void epicsShareAPI
 extern "C" double epicsShareAPI 
     epicsTimerQueuePassiveProcess ( epicsTimerQueuePassiveId pQueue )
 {
-    return pQueue->process ( epicsTime::getCurrent() );
+    try {
+        return pQueue->process ( epicsTime::getCurrent() );
+    }
+    catch ( ... ) {
+        return 1.0;
+    }
 }
 
 extern "C" epicsTimerId epicsShareAPI epicsTimerQueuePassiveCreateTimer (

src/libCom/timer/timer.cpp

@@ -197,7 +197,12 @@ void timer::show ( unsigned int level ) const
     }
     double delay;
     if ( this->curState == statePending || this->curState == stateActive ) {
-        delay = this->exp - epicsTime::getCurrent();
+        try {
+            delay = this->exp - epicsTime::getCurrent();
+        }
+        catch ( ... ) {
+            delay = - DBL_MAX;
+        }
     }
     else {
         delay = -DBL_MAX;

src/libCom/timer/timerPrivate.h

@@ -156,6 +156,9 @@ private:
     void run ();
     void reschedule ();
     double quantum ();
+    void _printLastChanceExceptionMessage ( 
+                const char * pExceptionTypeName,
+                const char * pExceptionContext );
     epicsTimerQueue & getEpicsTimerQueue ();
 	timerQueueActive ( const timerQueueActive & );
     timerQueueActive & operator = ( const timerQueueActive & );

src/libCom/timer/timerQueue.cpp

@@ -14,7 +14,8 @@
  *              505 665 1831
  */
 
-#include <stdio.h>
+#include <cstdio>
+#include <cfloat>
 
 #define epicsExportSharedSymbols
 #include "epicsGuard.h"
@@ -46,13 +47,22 @@ timerQueue::~timerQueue ()
 void timerQueue ::
     printExceptMsg ( const char * pName, const type_info & type )
 {
-    epicsTime cur = epicsTime :: getCurrent ();
-    double delay = cur - this->exceptMsgTimeStamp;
-    if ( delay >= exceptMsgMinPeriod ) {
-        this->exceptMsgTimeStamp = cur;
-        char date[64];
+    char date[64];
+    double delay;
+    try {
+        epicsTime cur = epicsTime :: getCurrent ();
+        delay = cur - this->exceptMsgTimeStamp;
         cur.strftime ( date, sizeof ( date ), 
                         "%a %b %d %Y %H:%M:%S.%f" );
+        if ( delay >= exceptMsgMinPeriod ) {
+            this->exceptMsgTimeStamp = cur;
+        }
+    }
+    catch ( ... ) {
+        delay = DBL_MAX;
+        strcpy ( date, "UKN DATE" );
+    }
+    if ( delay >= exceptMsgMinPeriod ) {
         // we dont touch the typeid for the timer expiration
         // notify interface here because they might have 
         // destroyed the timer during its callback

src/libCom/timer/timerQueueActive.cpp

@@ -18,6 +18,7 @@
 
 #define epicsExportSharedSymbols
 #include "timerPrivate.h"
+#include "errlog.h"
 
 #ifdef _MSC_VER
 #   pragma warning ( push )
@@ -63,13 +64,44 @@ timerQueueActive::~timerQueueActive ()
     this->exitEvent.signal ();
 }
 
-void timerQueueActive::run ()
+void timerQueueActive :: _printLastChanceExceptionMessage ( 
+    const char * pExceptionTypeName,
+    const char * pExceptionContext )
+{ 
+    char date[64];
+    try {
+        epicsTime cur = epicsTime :: getCurrent ();
+        cur.strftime ( date, sizeof ( date ), "%a %b %d %Y %H:%M:%S.%f");
+    }
+    catch ( ... ) {
+        strcpy ( date, "<UKN DATE>" );
+    }
+    errlogPrintf ( 
+        "timerQueueActive: Unexpected C++ exception \"%s\" with type \"%s\" "
+        "while processing timer queue, at %s\n",
+        pExceptionContext, pExceptionTypeName, date );
+}
+
+
+void timerQueueActive :: run ()
 {
     this->exitFlag = false;
     while ( ! this->terminateFlag ) {
-        double delay = this->queue.process ( epicsTime::getCurrent() );
-        debugPrintf ( ( "timer thread sleeping for %g sec (max)\n", delay ) );
-        this->rescheduleEvent.wait ( delay );
+        try {
+            double delay = this->queue.process ( epicsTime::getCurrent() );
+            debugPrintf ( ( "timer thread sleeping for %g sec (max)\n", delay ) );
+            this->rescheduleEvent.wait ( delay );
+        }
+        catch ( std :: exception & except ) {
+            _printLastChanceExceptionMessage (
+                typeid ( except ).name (), except.what () );
+            epicsThreadSleep ( 10.0 );
+        }
+        catch ( ... ) {
+            _printLastChanceExceptionMessage (
+                "catch ( ... )", "Non-standard C++ exception" );
+            epicsThreadSleep ( 10.0 );
+        }
     }
     this->exitFlag = true; 
     this->exitEvent.signal (); // no access to queue after exitEvent signal