From e19948daa72491d33cd5aa9b8619b7e093a16615 Mon Sep 17 00:00:00 2001
From: iNaKoll <inakoll@gmail.com>
Date: Thu, 10 Nov 2016 22:16:47 +0100
Subject: [PATCH] Fixes #5983: real_generator failure

---
 include/boost/spirit/home/karma/numeric/detail/real_utils.hpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/boost/spirit/home/karma/numeric/detail/real_utils.hpp b/include/boost/spirit/home/karma/numeric/detail/real_utils.hpp
index 526985d280..84ea67dd4b 100644
--- a/include/boost/spirit/home/karma/numeric/detail/real_utils.hpp
+++ b/include/boost/spirit/home/karma/numeric/detail/real_utils.hpp
@@ -105,7 +105,13 @@ namespace boost { namespace spirit { namespace karma
                     if (exp != -dim)
                         ++exp;
                     dim = static_cast<U>(-exp);
-                    n *= spirit::traits::pow10<U>(exp);
+                    // detect and handle denormalized numbers to prevent overflow in pow10
+                    if (exp > std::numeric_limits<U>::max_exponent10)
+                    {
+                        n *= spirit::traits::pow10<U>(std::numeric_limits<U>::max_exponent10);
+                        n *= spirit::traits::pow10<U>(exp - std::numeric_limits<U>::max_exponent10);
+                    } else
+                        n *= spirit::traits::pow10<U>(exp);
                 }
             }