From 90694bc3b9d0c1d36e9b1012c68a70276ed27fa9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20Neum=C3=BCller?=
 <christian+github@neumueller.me>
Date: Mon, 11 Mar 2019 17:56:55 +0100
Subject: [PATCH] Guard diagnostic_information against null what()

---
 include/boost/exception/diagnostic_information.hpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/boost/exception/diagnostic_information.hpp b/include/boost/exception/diagnostic_information.hpp
index b94ca44..ad22735 100644
--- a/include/boost/exception/diagnostic_information.hpp
+++ b/include/boost/exception/diagnostic_information.hpp
@@ -161,7 +161,7 @@ boost
                     core::demangle((be?(BOOST_EXCEPTION_DYNAMIC_TYPEID(*be)):(BOOST_EXCEPTION_DYNAMIC_TYPEID(*se))).type_->name()) << '\n';
 #endif
             if( with_what && se && verbose )
-                tmp << "std::exception::what: " << wh << '\n';
+                tmp << "std::exception::what: " << (wh ? wh : "(null)") << '\n';
             if( be )
                 if( char const * s=exception_detail::get_diagnostic_information(*be,tmp.str().c_str()) )
                     if( *s )