add interrupt handling (#12)

include/Interrupt.h

@@ -0,0 +1,7 @@
+#pragma once
+#include <atomic>
+
+namespace MqttClient {
+extern std::atomic<bool> interrupted;
+void onInterrupt(int ignored);
+} // namespace MqttClient

src/Interrupt.cpp

@@ -0,0 +1,9 @@
+#include "Interrupt.h"
+#include <atomic>
+
+namespace MqttClient {
+
+std::atomic<bool> interrupted(false);
+
+void onInterrupt(int ignored) { interrupted.store(true); }
+} // namespace MqttClient

src/main.cpp

@@ -1,5 +1,7 @@
 #include "Command.h"
 #include "Context.h"
+#include "Interrupt.h"
+#include <csignal>
 #include <getopt.h>
 #include <iostream>
 #include <memory>
@@ -8,6 +10,15 @@
 using namespace MqttClient;
 
 int main(int argc, char *argv[]) {
+    if (signal(SIGINT, onInterrupt) == SIG_ERR) {
+        std::cerr << "Unable to register SIGINT handler\n";
+        return 1;
+    }
+    if (signal(SIGTERM, onInterrupt) == SIG_ERR) {
+        std::cerr << "Unable to register SIGTERM handler\n";
+        return 1;
+    }
+
     auto res = parseContext(argc, argv);
     switch (res.code) {
     case ParseResultCode::HELP: