Return unsuccessful exit code if error occurs

example/example.cpp

@@ -25,6 +25,7 @@
 //
 // spdlog usage example
 //
+#include <cstdlib> // EXIT_FAILURE
 #include <iostream>
 #include "spdlog/spdlog.h"
 
@@ -106,7 +107,9 @@ int main(int, char*[])
     catch (const spd::spdlog_ex& ex)
     {
         std::cout << "Log failed: " << ex.what() << std::endl;
+        return EXIT_FAILURE;
     }
+    return EXIT_SUCCESS;
 }