diff --git a/include/boost/detail/bitmask.hpp b/include/boost/detail/bitmask.hpp
new file mode 100644
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+++ b/include/boost/detail/bitmask.hpp
@@ -0,0 +1,58 @@
+//  boost/detail/bitmask.hpp  ------------------------------------------------//
+
+//  Copyright Beman Dawes 2006
+
+//  Distributed under the Boost Software License, Version 1.0
+//  http://www.boost.org/LICENSE_1_0.txt
+
+//  Usage:  enum foo { a=1, b=2, c=4 };
+//          BOOST_BITMASK( foo )
+//
+//          void f( foo arg );
+//          ...
+//          f( a | c );
+//
+//  See [bitmask.types] in the C++ standard for the formal specification
+
+#ifndef BOOST_BITMASK_HPP
+#define BOOST_BITMASK_HPP
+
+#include <boost/config.hpp>
+#include <boost/cstdint.hpp>
+
+#define BOOST_BITMASK(Bitmask)                                            \
+                                                                          \
+  inline BOOST_CONSTEXPR Bitmask operator| (Bitmask x , Bitmask y )       \
+  { return static_cast<Bitmask>( static_cast<boost::int_least32_t>(x)     \
+      | static_cast<boost::int_least32_t>(y)); }                          \
+                                                                          \
+  inline BOOST_CONSTEXPR Bitmask operator& (Bitmask x , Bitmask y )       \
+  { return static_cast<Bitmask>( static_cast<boost::int_least32_t>(x)     \
+      & static_cast<boost::int_least32_t>(y)); }                          \
+                                                                          \
+  inline BOOST_CONSTEXPR Bitmask operator^ (Bitmask x , Bitmask y )       \
+  { return static_cast<Bitmask>( static_cast<boost::int_least32_t>(x)     \
+      ^ static_cast<boost::int_least32_t>(y)); }                          \
+                                                                          \
+  inline BOOST_CONSTEXPR Bitmask operator~ (Bitmask x )                   \
+  { return static_cast<Bitmask>(~static_cast<boost::int_least32_t>(x)); } \
+                                                                          \
+  inline Bitmask & operator&=(Bitmask& x , Bitmask y)                     \
+  { x = x & y ; return x ; }                                              \
+                                                                          \
+  inline Bitmask & operator|=(Bitmask& x , Bitmask y)                     \
+  { x = x | y ; return x ; }                                              \
+                                                                          \
+  inline Bitmask & operator^=(Bitmask& x , Bitmask y)                     \
+  { x = x ^ y ; return x ; }                                              \
+                                                                          \
+  /* Boost extensions to [bitmask.types] */                               \
+                                                                          \
+  inline BOOST_CONSTEXPR bool operator!(Bitmask x)                        \
+  { return !static_cast<int>(x); }                                        \
+                                                                          \
+  inline BOOST_CONSTEXPR bool bitmask_set(Bitmask x)                      \
+  { return !!x; }
+
+#endif // BOOST_BITMASK_HPP
+