diff --git a/include/mio/mmap.hpp b/include/mio/mmap.hpp
index b7803ea..cb686ca 100644
--- a/include/mio/mmap.hpp
+++ b/include/mio/mmap.hpp
@@ -128,7 +128,8 @@ public:
         map(handle, offset, length, error);
         if(error) { throw std::system_error(error); }
     }
-#endif
+#endif // __cpp_exceptions
+
     /**
      * `basic_mmap` has single-ownership semantics, so transferring ownership
      * may only be accomplished by moving the object.
diff --git a/include/mio/shared_mmap.hpp b/include/mio/shared_mmap.hpp
index 19be761..b914c18 100644
--- a/include/mio/shared_mmap.hpp
+++ b/include/mio/shared_mmap.hpp
@@ -112,7 +112,7 @@ public:
         map(handle, offset, length, error);
         if(error) { throw std::system_error(error); }
     }
-#endif
+#endif // __cpp_exceptions
 
     /**
      * If this is a read-write mapping and the last reference to the mapping,