If syncProvder is set but does not return time, subsequent calls to now() should try to sync.

.gitignore

@@ -0,0 +1 @@
+version.h

Time.cpp

@@ -237,6 +237,7 @@ time_t makeTime(tmElements_t &tm){
 static uint32_t sysTime = 0;
 static uint32_t prevMillis = 0;
 static uint32_t nextSyncTime = 0;
+static uint32_t lastSyncTime = 0;
 static timeStatus_t Status = timeNotSet;
 
 getExternalTime getTimePtr;  // pointer to external sync function
@@ -248,9 +249,9 @@ time_t sysUnsyncedTime = 0; // the time sysTime unadjusted by sync
 
 
 time_t now() {
-	// calculate number of seconds passed since last call to now()
+  // calculate number of seconds passed since last call to now()
   while (millis() - prevMillis >= 1000) {
-		// millis() and prevMillis are both unsigned ints thus the subtraction will always be the absolute value of the difference
+    // millis() and prevMillis are both unsigned ints thus the subtraction will always be the absolute value of the difference
     sysTime++;
     prevMillis += 1000;	
 #ifdef TIME_DRIFT_INFO
@@ -262,9 +263,13 @@ time_t now() {
       time_t t = getTimePtr();
       if (t != 0) {
         setTime(t);
+      } else if(timeNotSet == Status) {
+        // getTimePtr returned 0 and time has not yet been set, i.e. this was not
+        // a temporarily failure, we have not been able to sync at all.
+        // Do nothing so a new attempt to sync will be made next time now() is called.
       } else {
         nextSyncTime = sysTime + syncInterval;
-        Status = (Status == timeNotSet) ?  timeNotSet : timeNeedsSync;
+        Status = timeNeedsSync;
       }
     }
   }  
@@ -277,7 +282,8 @@ void setTime(time_t t) {
    sysUnsyncedTime = t;   // store the time of the first call to set a valid Time   
 #endif
 
-  sysTime = (uint32_t)t;  
+  sysTime = (uint32_t)t;
+	lastSyncTime = (uint32_t)t;
   nextSyncTime = (uint32_t)t + syncInterval;
   Status = timeSet;
   prevMillis = millis();  // restart counting from now (thanks to Korman for this fix)
@@ -319,3 +325,7 @@ void setSyncInterval(time_t interval){ // set the number of seconds between re-s
   syncInterval = (uint32_t)interval;
   nextSyncTime = sysTime + syncInterval;
 }
+
+time_t getLastSyncTime(){
+	return (time_t)lastSyncTime;
+}

TimeLib.h

@@ -15,7 +15,7 @@
 #ifndef __AVR__
 #include <sys/types.h> // for __time_t_defined, but avr libc lacks sys/types.h
 #endif
-
+#include "version.h"
 
 #if !defined(__time_t_defined) // avoid conflict with newlib or other posix libc
 typedef unsigned long time_t;
@@ -133,6 +133,7 @@ char* dayShortStr(uint8_t day);
 timeStatus_t timeStatus(); // indicates if time has been set and recently synchronized
 void    setSyncProvider( getExternalTime getTimeFunction); // identify the external time provider
 void    setSyncInterval(time_t interval); // set the number of seconds between re-sync
+time_t  getLastSyncTime(); // get time when last successful sync was made 
 
 /* low level functions to convert to and from system time                     */
 void breakTime(time_t time, tmElements_t &tm);  // break time_t into elements