Shutdown asynchronously when sigint is received (#844)

Signed-off-by: Ivan Santiago Paunovic <ivanpauno@ekumenlabs.com>

rclpy/src/rclpy/signal_handler.cpp

@@ -57,7 +57,6 @@ std::thread g_deferred_signal_handling_thread;
 
 // relying on python GIL for safety
 std::atomic<bool> g_signal_handler_installed = false;
-std::atomic<bool> g_is_sigterm;
 
 void
 notify_signal_handler() noexcept
@@ -141,9 +140,7 @@ setup_deferred_signal_handler()
  wait_for_signal();
  if (g_signal_handler_installed.load()) {
  trigger_guard_conditions();
- if (g_is_sigterm.exchange(false)) {
- rclpy::shutdown_contexts();
- }
+ rclpy::shutdown_contexts();
  }
  }
  });
@@ -328,7 +325,6 @@ DEFINE_SIGNAL_HANDLER(rclpy_sigterm_handler)
  // Try to unregister again.
  unregister_sigint_signal_handler();
  } else {
- g_is_sigterm.exchange(true);
  notify_signal_handler();
  }
 }