diff --git a/src/exception.cpp b/src/exception.cpp
index 641659e..640454a 100644
--- a/src/exception.cpp
+++ b/src/exception.cpp
@@ -131,6 +131,11 @@
     return errWhat;
 }
 
+int InvalidEnumString::get_errno() const noexcept
+{
+    return EINVAL;
+}
+
 UnpackPropertyError::UnpackPropertyError(std::string_view propertyName,
                                          std::string_view reason) :
     propertyName(propertyName),
@@ -152,6 +157,11 @@
     return errWhat;
 }
 
+int UnpackPropertyError::get_errno() const noexcept
+{
+    return EINVAL;
+}
+
 } // namespace exception
 } // namespace sdbusplus