From a5b09b49e8d5fc8de43c558b74c1668fe6933c80 Mon Sep 17 00:00:00 2001
From: Christos <cstamatopoulos@users.noreply.github.com>
Date: Mon, 16 Apr 2018 23:57:22 -0700
Subject: [PATCH] add operator~

---
 include/flags/flags.hpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/flags/flags.hpp b/include/flags/flags.hpp
index a17f6d76e..f2d2dae20 100644
--- a/include/flags/flags.hpp
+++ b/include/flags/flags.hpp
@@ -305,5 +305,12 @@ constexpr auto operator^(E e1, E e2) noexcept
   return flags::flags<E>(e1) ^ e2;
 }
 
+template 
+constexpr auto operator~(E e1) noexcept
+-> typename std::enable_if<flags::is_flags::value,
+                           flags::flags>::type{
+  return ~flags::flags(e1);
+}
+
 
 #endif // ENUM_CLASS_FLAGS_HPP