From fa1d0e59954873403c897ffbb996b01d1faeffd2 Mon Sep 17 00:00:00 2001
From: Bjarne Stroustrup <bjarne@stroustrup.com>
Date: Wed, 17 May 2017 14:25:13 -0400
Subject: [PATCH] exceptionsand const

Added to E.15
---
 CppCoreGuidelines.md | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/CppCoreGuidelines.md b/CppCoreGuidelines.md
index aedefc4..53c3156 100644
--- a/CppCoreGuidelines.md
+++ b/CppCoreGuidelines.md
@@ -14139,10 +14139,16 @@ To prevent slicing.
         // ...
     }
 
-Instead, use:
+Instead, use a reference:
 
     catch (exception& e) { /* ... */ }
 
+of - typically better stil - a `const` reference:
+
+    catch (const exception& e) { /* ... */ }
+
+Most handlers do not modify their exception and in general we [recommend use of `const`](#Res-const).
+
 ##### Enforcement
 
 Flag by-value exceptions if their types are part of a hierarchy (could require whole-program analysis to be perfect).