timed start measurment time. to syncronize the steady-time with the wall-time the wall-clock call has been surrounded by calls to steady-clock and the half of the difference added as uncertainty parameter, to the config file.

radangeld/main.cpp

@@ -79,6 +79,7 @@ struct measurement_properties
 	std::chrono::time_point<std::chrono::system_clock> starttime;
 	std::chrono::time_point<std::chrono::system_clock> endtime;
 
+    std::chrono::time_point<std::chrono::steady_clock> starterrortime;
 	std::chrono::time_point<std::chrono::steady_clock> startmeastime;
 };
 
@@ -106,6 +107,7 @@ int writeprotocol (const std::string &filename, measurement_properties &mp)
 	libconfig::Setting &measurement = root.add ("Measurement", libconfig::Setting::TypeGroup);
 
 	measurement.add ("StartTime", libconfig::Setting::TypeString) = date::format ("%F %T ", date::make_zoned (date::current_zone(), mp.starttime) ) + date::current_zone()->name();
+	measurement.add ("StartTimeError_ns", libconfig::Setting::TypeInt64) = std::chrono::duration_cast<std::chrono::nanoseconds>(mp.startmeastime-mp.starterrortime).count()/2;
 	measurement.add ("EndTime", libconfig::Setting::TypeString) = date::format ("%F %T ", date::make_zoned (date::current_zone(), mp.endtime) ) + date::current_zone()->name();
 	measurement.add ("RunAsDaemon", libconfig::Setting::TypeBoolean) = mp.demonize;
 	measurement.add ("MaxIntegrationTime_s", libconfig::Setting::TypeInt) = static_cast<int> (mp.maxduration.count() );
@@ -185,6 +187,7 @@ void read_hid_reports (measurement_properties &mp, zmqpp::context &zmqc)
 	if (mp.demonize)
 		sd_notifyf(0, "READY=1\nSTATUS=Processing events…\nMAINPID=%lu", (unsigned long) getpid());
                  
+    mp.starterrortime = std::chrono::steady_clock::now();
 	mp.starttime = std::chrono::system_clock::now();
 	mp.startmeastime = std::chrono::steady_clock::now();