diff --git a/gpio-util/main.cpp b/gpio-util/main.cpp
index 0cfacf4..82cbed4 100644
--- a/gpio-util/main.cpp
+++ b/gpio-util/main.cpp
@@ -177,7 +177,7 @@
     {
         function->second(gpio, delay);
     }
-    catch (std::runtime_error& e)
+    catch (const std::runtime_error& e)
     {
         std::cerr << e.what();
         return -1;
diff --git a/gpioMonMain.cpp b/gpioMonMain.cpp
index 4b8b052..f8084a3 100644
--- a/gpioMonMain.cpp
+++ b/gpioMonMain.cpp
@@ -59,7 +59,7 @@
     {
         app.parse(argc, argv);
     }
-    catch (CLI::Error& e)
+    catch (const CLI::Error& e)
     {
         return app.exit(e);
     }
diff --git a/presence/gpio_presence.cpp b/presence/gpio_presence.cpp
index 2c448da..765ca55 100644
--- a/presence/gpio_presence.cpp
+++ b/presence/gpio_presence.cpp
@@ -216,7 +216,7 @@
             file << device;
             file.close();
         }
-        catch (std::exception& e)
+        catch (const std::exception& e)
         {
             auto err = errno;