How does a robot control system properly shut down?

#include "MySafetyProperties.hpp>
#include <signal.h>
 
void signalHandler(int signum) {
	SafetySystem::exitHandler();
}
 
int main() {
  signal(SIGHUP, signalHandler);
  signal(SIGINT, signalHandler);
  signal(SIGQUIT, signalHandler);
  signal(SIGKILL, signalHandler);
  signal(SIGTERM, signalHandler);
  signal(SIGPWR, signalHandler);
 
  ...
 
  // Create and initialize safety system
  double period = 1;
  MySafetyProperties ssProperties;
  SafetySystem safetySys(ssProperties, period);
 
  ... 
}

exitFunction = [&](SafetyContext* privateContext) {
  privateContext->triggerEvent(seShutDown);
};

SafetyEvent seShutDown;