From 8e2c5f19429f10386524f58bb764d8661098824a Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Mon, 16 Nov 2015 17:57:53 +1100
Subject: [PATCH] maths: explanatory header for sign()

---
 maths.hpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/maths.hpp b/maths.hpp
index e9499a82..1a4c5214 100644
--- a/maths.hpp
+++ b/maths.hpp
@@ -135,7 +135,8 @@ namespace util {
     digits (const T& value);
 
 
-    //-----------------------------------------------------------------------------
+    ///----------------------------------------------------------------------------
+    /// return positive or negative unit value corresponding to the input.
     template <typename T>
     constexpr std::enable_if_t<
         std::is_signed<T>::value && std::is_integral<T>::value, T
@@ -145,7 +146,10 @@ namespace util {
         return t < 0 ? -1 : 1;
     }
 
-    //-------------------------------------------------------------------------
+    ///------------------------------------------------------------------------
+    /// return positive or negative unit value corresponding to the input.
+    /// guaranteed to give correct results for signed zeroes, use another
+    /// method if extreme speed is important.
     template <typename T>
     constexpr std::enable_if_t<
         std::is_floating_point<T>::value, T