Third try for clang-win

Make error_code and error_condition constexpr, as proposed in https://cplusplus.github.io/LWG/issue2992

.travis.yml

@@ -109,7 +109,7 @@ matrix:
 
     - os: linux
       compiler: g++-7
-      env: UBSAN=1 TOOLSET=gcc COMPILER=g++-7 CXXSTD=03,11,14,17 UBSAN_OPTIONS=print_stacktrace=1
+      env: UBSAN=1 TOOLSET=gcc COMPILER=g++-7 CXXSTD=03,11,14,17 UBSAN_OPTIONS=print_stacktrace=1 LINKFLAGS=-fuse-ld=gold
       addons:
         apt:
           packages:
@@ -117,6 +117,16 @@ matrix:
           sources:
             - ubuntu-toolchain-r-test
 
+    - os: linux
+      compiler: g++-8
+      env: TOOLSET=gcc COMPILER=g++-8 CXXSTD=03,11,14,17
+      addons:
+        apt:
+          packages:
+            - g++-8
+          sources:
+            - ubuntu-toolchain-r-test
+
     - os: linux
       compiler: clang++
       env: TOOLSET=clang COMPILER=clang++ CXXSTD=03,11
@@ -202,6 +212,7 @@ matrix:
         apt:
           packages:
             - clang-4.0
+            - libstdc++-4.9-dev
           sources:
             - ubuntu-toolchain-r-test
             - llvm-toolchain-trusty-4.0
@@ -213,6 +224,7 @@ matrix:
         apt:
           packages:
             - clang-5.0
+            - libstdc++-4.9-dev
           sources:
             - ubuntu-toolchain-r-test
             - llvm-toolchain-trusty-5.0
@@ -224,10 +236,23 @@ matrix:
         apt:
           packages:
             - clang-5.0
+            - libstdc++-4.9-dev
           sources:
             - ubuntu-toolchain-r-test
             - llvm-toolchain-trusty-5.0
 
+    - os: linux
+      compiler: clang++-6.0
+      env: TOOLSET=clang COMPILER=clang++-6.0 CXXSTD=03,11,14,17
+      addons:
+        apt:
+          packages:
+            - clang-6.0
+            - libstdc++-4.9-dev
+          sources:
+            - ubuntu-toolchain-r-test
+            - llvm-toolchain-trusty-6.0
+
     - os: linux
       compiler: clang++-libc++
       env: TOOLSET=clang COMPILER=clang++-libc++ CXXSTD=03,11,14,1z
@@ -264,7 +289,7 @@ install:
 script:
   - |-
     echo "using $TOOLSET : : $COMPILER ;" > ~/user-config.jam
-  - ./b2 -j3 libs/system/test toolset=$TOOLSET cxxstd=$CXXSTD variant=debug,release ${UBSAN:+cxxflags=-fsanitize=undefined cxxflags=-fno-sanitize-recover=undefined linkflags=-fsanitize=undefined define=UBSAN=1 debug-symbols=on}
+  - ./b2 -j3 libs/system/test toolset=$TOOLSET cxxstd=$CXXSTD variant=debug,release ${UBSAN:+cxxflags=-fsanitize=undefined cxxflags=-fno-sanitize-recover=undefined linkflags=-fsanitize=undefined define=UBSAN=1 debug-symbols=on} ${LINKFLAGS:+linkflags=$LINKFLAGS}
 
 notifications:
   email:

appveyor.yml

@@ -14,6 +14,10 @@ branches:
 
 environment:
   matrix:
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+      TOOLSET: clang-win
+      CLANG_WIN: 1
+      USER_CONFIG: "using clang-win : : clang-cl.exe : <compatibility>vc14 ;"
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2013
       TOOLSET: msvc-9.0
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2013
@@ -36,6 +40,13 @@ environment:
       ADDPATH: C:\cygwin\bin;
       TOOLSET: gcc
       CXXSTD: 03,11
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2013
+      ADDPATH: C:\cygwin64\bin;
+      TOOLSET: gcc
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2013
+      ADDPATH: C:\cygwin64\bin;
+      TOOLSET: gcc
+      CXXSTD: 03,11
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2013
       ADDPATH: C:\mingw\bin;
       TOOLSET: gcc
@@ -70,4 +81,5 @@ build: off
 test_script:
   - PATH=%ADDPATH%%PATH%
   - if not "%CXXSTD%" == "" set CXXSTD=cxxstd=%CXXSTD%
+  - if not "%USER_CONFIG%" == "" echo %USER_CONFIG% > %HOMEDRIVE%%HOMEPATH%\user-config.jam
   - b2 -j3 libs/system/test toolset=%TOOLSET% variant=debug,release %CXXSTD%

include/boost/system/detail/error_code.ipp

@@ -35,45 +35,22 @@
 //--------------------------------------------------------------------------------------//
 namespace boost
 {
-    namespace system
-    {
+
+namespace system
+{
 
 namespace detail
 {
 
-  //  standard error categories  -------------------------------------------------------//
-
-  class generic_error_category : public error_category
-  {
-  public:
-    generic_error_category(){}
-    const char *   name() const BOOST_SYSTEM_NOEXCEPT;
-    std::string    message( int ev ) const;
-  };
-
-  class system_error_category : public error_category
-  {
-  public:
-    system_error_category(){}
-    const char *        name() const BOOST_SYSTEM_NOEXCEPT;
-    std::string         message( int ev ) const;
-    error_condition     default_error_condition( int ev ) const BOOST_SYSTEM_NOEXCEPT;
-  };
-
 #ifdef BOOST_ERROR_CODE_HEADER_ONLY
-# define BOOST_SYSTEM_INLINE inline
+# define BOOST_SYSTEM_DECL_ inline
 #else
-# define BOOST_SYSTEM_INLINE
+# define BOOST_SYSTEM_DECL_ BOOST_SYSTEM_DECL
 #endif
 
   //  generic_error_category implementation  ---------------------------------//
 
-  BOOST_SYSTEM_INLINE const char * generic_error_category::name() const BOOST_SYSTEM_NOEXCEPT
-  {
-    return "generic";
-  }
-
-  BOOST_SYSTEM_INLINE std::string generic_error_category::message( int ev ) const
+  BOOST_SYSTEM_DECL_ std::string generic_error_category::message( int ev ) const
   {
     using namespace boost::system::errc;
 #if defined(__PGI)
@@ -166,12 +143,7 @@ namespace detail
   }
   //  system_error_category implementation  --------------------------------------------//
 
-  BOOST_SYSTEM_INLINE const char * system_error_category::name() const BOOST_SYSTEM_NOEXCEPT
-  {
-    return "system";
-  }
-
-  BOOST_SYSTEM_INLINE error_condition system_error_category::default_error_condition( int ev ) const
+  BOOST_SYSTEM_DECL_ error_condition system_error_category::default_error_condition( int ev ) const
     BOOST_SYSTEM_NOEXCEPT
   {
     using namespace boost::system::errc;
@@ -376,13 +348,13 @@ namespace detail
 
 # if !defined( BOOST_WINDOWS_API )
 
-  BOOST_SYSTEM_INLINE std::string system_error_category::message( int ev ) const
+  BOOST_SYSTEM_DECL_ std::string system_error_category::message( int ev ) const
   {
     return generic_category().message( ev );
   }
 # else
 
-  BOOST_SYSTEM_INLINE std::string system_error_category::message( int ev ) const
+  BOOST_SYSTEM_DECL_ std::string system_error_category::message( int ev ) const
   {
 #if defined(UNDER_CE) || BOOST_PLAT_WINDOWS_RUNTIME || defined(BOOST_NO_ANSI_APIS)
     std::wstring buf(128, wchar_t());
@@ -461,7 +433,7 @@ namespace detail
   }
 # endif
 
-#undef BOOST_SYSTEM_INLINE
+#undef BOOST_SYSTEM_DECL_
 
 } // namespace detail
 
@@ -474,23 +446,51 @@ namespace detail
                                          //  address for comparison purposes
 # endif
 
-# ifdef BOOST_ERROR_CODE_HEADER_ONLY
-#   define BOOST_SYSTEM_LINKAGE inline
-# else
-#   define BOOST_SYSTEM_LINKAGE BOOST_SYSTEM_DECL
-# endif
+#if defined(BOOST_ERROR_CODE_HEADER_ONLY)
 
-    BOOST_SYSTEM_LINKAGE const error_category & system_category() BOOST_SYSTEM_NOEXCEPT
-    {
-      static const detail::system_error_category  system_category_const;
-      return system_category_const;
-    }
+// defined in error_code.hpp
 
-    BOOST_SYSTEM_LINKAGE const error_category & generic_category() BOOST_SYSTEM_NOEXCEPT
-    {
-      static const detail::generic_error_category generic_category_const;
-      return generic_category_const;
-    }
+#elif defined(BOOST_SYSTEM_HAS_CONSTEXPR)
+
+namespace detail
+{
+
+BOOST_SYSTEM_REQUIRE_CONST_INIT BOOST_SYSTEM_DECL system_error_category system_category_instance;
+BOOST_SYSTEM_REQUIRE_CONST_INIT BOOST_SYSTEM_DECL generic_error_category generic_category_instance;
+
+BOOST_SYSTEM_DECL const error_category & system_category_ncx() BOOST_SYSTEM_NOEXCEPT
+{
+    return system_category_instance;
+}
+
+BOOST_SYSTEM_DECL const error_category & generic_category_ncx() BOOST_SYSTEM_NOEXCEPT
+{
+    return generic_category_instance;
+}
+
+} // namespace detail
+
+#else
+
+namespace detail
+{
+
+BOOST_SYSTEM_DECL const error_category & system_category_ncx() BOOST_SYSTEM_NOEXCEPT
+{
+    static const detail::system_error_category system_category_instance;
+    return system_category_instance;
+}
+
+BOOST_SYSTEM_DECL const error_category & generic_category_ncx() BOOST_SYSTEM_NOEXCEPT
+{
+    static const detail::generic_error_category generic_category_instance;
+    return generic_category_instance;
+}
+
+} // namespace detail
+
+#endif
+
+} // namespace system
 
-  } // namespace system
 } // namespace boost

include/boost/system/error_code.hpp

@@ -39,6 +39,27 @@
 #define BOOST_SYSTEM_NOEXCEPT BOOST_NOEXCEPT
 #endif
 
+#if !defined(BOOST_NO_CXX14_CONSTEXPR)
+# define BOOST_SYSTEM_HAS_CONSTEXPR
+#endif
+
+#if defined(__GNUC__) && (__GNUC__ == 7 && __GNUC_MINOR__ < 4) && __cplusplus >= 201700L
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83835
+#  undef BOOST_SYSTEM_HAS_CONSTEXPR
+#endif
+
+#if defined(__clang__) && defined(_MSC_VER) && defined(_CPPLIB_VER)
+// Clang on Windows with MSVC headers, the constructor of std::error_category
+// is not constexpr at least up to VS2017 15.7.x (_MSVC_STL_UPDATE 201803)
+#  undef BOOST_SYSTEM_HAS_CONSTEXPR
+#endif
+
+#if defined(BOOST_SYSTEM_HAS_CONSTEXPR)
+# define BOOST_SYSTEM_CONSTEXPR constexpr
+#else
+# define BOOST_SYSTEM_CONSTEXPR
+#endif
+
 namespace boost
 {
   namespace system
@@ -186,31 +207,6 @@ namespace boost
 
     //  --------------------------------------------------------------------------------//
 
-    class error_category;
-
-    //  predefined error categories  ---------------------------------------------------//
-
-#ifdef BOOST_ERROR_CODE_HEADER_ONLY
-    inline const error_category &  system_category() BOOST_SYSTEM_NOEXCEPT;
-    inline const error_category &  generic_category() BOOST_SYSTEM_NOEXCEPT;
-#else
-    BOOST_SYSTEM_DECL const error_category &  system_category() BOOST_SYSTEM_NOEXCEPT;
-    BOOST_SYSTEM_DECL const error_category &  generic_category() BOOST_SYSTEM_NOEXCEPT;
-#endif
-    //  deprecated synonyms ------------------------------------------------------------//
-
-#ifdef BOOST_SYSTEM_ENABLE_DEPRECATED
-    inline const error_category &  get_system_category() { return system_category(); }
-    inline const error_category &  get_generic_category() { return generic_category(); }
-    inline const error_category &  get_posix_category() { return generic_category(); }
-    static const error_category &  posix_category BOOST_ATTRIBUTE_UNUSED
-      = generic_category();
-    static const error_category &  errno_ecat     BOOST_ATTRIBUTE_UNUSED
-      = generic_category();
-    static const error_category &  native_ecat    BOOST_ATTRIBUTE_UNUSED
-      = system_category();
-#endif
-
 #ifdef BOOST_MSVC
 #pragma warning(push)
 // 'this' : used in base member initializer list
@@ -233,7 +229,7 @@ namespace boost
 
       public:
 
-        explicit std_category( boost::system::error_category const * pc ): pc_( pc )
+        BOOST_SYSTEM_CONSTEXPR explicit std_category( boost::system::error_category const * pc ): pc_( pc )
         {
         }
 
@@ -259,7 +255,7 @@ namespace boost
 
     public:
 
-      error_category() BOOST_SYSTEM_NOEXCEPT: std_cat_( this ) {}
+      BOOST_SYSTEM_CONSTEXPR error_category() BOOST_SYSTEM_NOEXCEPT: std_cat_( this ) {}
 
       operator std::error_category const & () const BOOST_SYSTEM_NOEXCEPT
       {
@@ -284,7 +280,7 @@ namespace boost
 
       public:
 
-        explicit std_category( boost::system::error_category const * pc ): pc_( pc )
+        BOOST_SYSTEM_CONSTEXPR explicit std_category( boost::system::error_category const * pc ): pc_( pc )
         {
         }
 
@@ -310,7 +306,7 @@ namespace boost
 
     public:
 
-      error_category() BOOST_SYSTEM_NOEXCEPT: std_cat_( this ) {}
+      BOOST_SYSTEM_CONSTEXPR error_category() BOOST_SYSTEM_NOEXCEPT: std_cat_( this ) {}
 
 #endif
 
@@ -326,19 +322,193 @@ namespace boost
         BOOST_SYSTEM_NOEXCEPT;
       inline virtual bool             equivalent( const error_code & code,
                                            int condition ) const  BOOST_SYSTEM_NOEXCEPT;
-
-      bool operator==(const error_category & rhs) const BOOST_SYSTEM_NOEXCEPT
-        { return this == &rhs; }
-      bool operator!=(const error_category & rhs) const BOOST_SYSTEM_NOEXCEPT
-        { return this != &rhs; }
-      bool operator<( const error_category & rhs ) const BOOST_SYSTEM_NOEXCEPT
-        { return std::less<const error_category*>()( this, &rhs ); }
     };
 
+    BOOST_SYSTEM_CONSTEXPR inline bool operator==( const error_category & lhs,
+        const error_category & rhs ) BOOST_SYSTEM_NOEXCEPT
+        { return &lhs == &rhs; }
+
+    BOOST_SYSTEM_CONSTEXPR inline bool operator!=( const error_category & lhs,
+        const error_category & rhs ) BOOST_SYSTEM_NOEXCEPT
+        { return &lhs != &rhs; }
+
+    inline bool operator<( const error_category & lhs,
+        const error_category & rhs ) BOOST_SYSTEM_NOEXCEPT
+        { return std::less<const error_category*>()( &lhs, &rhs ); }
+
 #ifdef BOOST_MSVC
 #pragma warning(pop)
 #endif
 
+    //  predefined error categories  ---------------------------------------------------//
+
+namespace detail
+{
+
+#ifdef BOOST_ERROR_CODE_HEADER_ONLY
+# define BOOST_SYSTEM_DECL_
+#else
+# define BOOST_SYSTEM_DECL_ BOOST_SYSTEM_DECL
+#endif
+
+class generic_error_category: public error_category
+{
+public:
+
+    // clang++ 3.8 and below: initialization of const object
+    // requires a user-provided default constructor
+    BOOST_SYSTEM_CONSTEXPR generic_error_category() BOOST_SYSTEM_NOEXCEPT
+    {
+    }
+
+    const char * name() const BOOST_SYSTEM_NOEXCEPT
+    {
+        return "generic";
+    }
+
+    BOOST_SYSTEM_DECL_ std::string message( int ev ) const;
+};
+
+class system_error_category: public error_category
+{
+public:
+
+    BOOST_SYSTEM_CONSTEXPR system_error_category() BOOST_SYSTEM_NOEXCEPT
+    {
+    }
+
+    const char * name() const BOOST_SYSTEM_NOEXCEPT
+    {
+        return "system";
+    }
+
+    BOOST_SYSTEM_DECL_ std::string message( int ev ) const;
+    BOOST_SYSTEM_DECL_ error_condition default_error_condition( int ev ) const BOOST_SYSTEM_NOEXCEPT;
+};
+
+#undef BOOST_SYSTEM_DECL_
+
+} // namespace detail
+
+#define BOOST_SYSTEM_REQUIRE_CONST_INIT
+
+#if defined(__has_cpp_attribute)
+#if __has_cpp_attribute(clang::require_constant_initialization)
+# undef BOOST_SYSTEM_REQUIRE_CONST_INIT
+# define BOOST_SYSTEM_REQUIRE_CONST_INIT [[clang::require_constant_initialization]]
+#endif
+#endif
+
+#if defined(BOOST_ERROR_CODE_HEADER_ONLY)
+
+# if defined(BOOST_SYSTEM_HAS_CONSTEXPR)
+
+namespace detail
+{
+
+template<class T> struct cat_holder
+{
+    static system_error_category system_category_instance;
+    static generic_error_category generic_category_instance;
+};
+
+template<class T> BOOST_SYSTEM_REQUIRE_CONST_INIT system_error_category cat_holder<T>::system_category_instance;
+template<class T> BOOST_SYSTEM_REQUIRE_CONST_INIT generic_error_category cat_holder<T>::generic_category_instance;
+
+} // namespace detail
+
+constexpr const error_category & system_category() BOOST_SYSTEM_NOEXCEPT
+{
+    return detail::cat_holder<void>::system_category_instance;
+}
+
+constexpr const error_category & generic_category() BOOST_SYSTEM_NOEXCEPT
+{
+    return detail::cat_holder<void>::generic_category_instance;
+}
+
+# else
+
+inline const error_category & system_category() BOOST_SYSTEM_NOEXCEPT
+{
+    static const detail::system_error_category system_category_instance;
+    return system_category_instance;
+}
+
+inline const error_category & generic_category() BOOST_SYSTEM_NOEXCEPT
+{
+    static const detail::generic_error_category generic_category_instance;
+    return generic_category_instance;
+}
+
+# endif
+
+#elif defined(BOOST_SYSTEM_HAS_CONSTEXPR)
+
+namespace detail
+{
+
+#if defined(BOOST_SYSTEM_SOURCE)
+
+// clang++ requires a strictly matching declaration
+BOOST_SYSTEM_DECL extern system_error_category system_category_instance;
+BOOST_SYSTEM_DECL extern generic_error_category generic_category_instance;
+
+#else
+
+extern system_error_category system_category_instance;
+extern generic_error_category generic_category_instance;
+
+#endif
+
+} // namespace detail
+
+constexpr const error_category & system_category() BOOST_SYSTEM_NOEXCEPT
+{
+    return detail::system_category_instance;
+}
+
+constexpr const error_category & generic_category() BOOST_SYSTEM_NOEXCEPT
+{
+    return detail::generic_category_instance;
+}
+
+#else
+
+namespace detail
+{
+
+BOOST_SYSTEM_DECL const error_category & system_category_ncx() BOOST_SYSTEM_NOEXCEPT;
+BOOST_SYSTEM_DECL const error_category & generic_category_ncx() BOOST_SYSTEM_NOEXCEPT;
+
+} // namespace detail
+
+inline const error_category & system_category() BOOST_SYSTEM_NOEXCEPT
+{
+    return detail::system_category_ncx();
+}
+
+inline const error_category & generic_category() BOOST_SYSTEM_NOEXCEPT
+{
+    return detail::generic_category_ncx();
+}
+
+#endif
+
+    //  deprecated synonyms ------------------------------------------------------------//
+
+#ifdef BOOST_SYSTEM_ENABLE_DEPRECATED
+    inline const error_category &  get_system_category() { return system_category(); }
+    inline const error_category &  get_generic_category() { return generic_category(); }
+    inline const error_category &  get_posix_category() { return generic_category(); }
+    static const error_category &  posix_category BOOST_ATTRIBUTE_UNUSED
+      = generic_category();
+    static const error_category &  errno_ecat     BOOST_ATTRIBUTE_UNUSED
+      = generic_category();
+    static const error_category &  native_ecat    BOOST_ATTRIBUTE_UNUSED
+      = system_category();
+#endif
+
     //  class error_condition  ---------------------------------------------------------//
 
     //  error_conditions are portable, error_codes are system or library specific
@@ -348,8 +518,8 @@ namespace boost
     public:
 
       // constructors:
-      error_condition() BOOST_SYSTEM_NOEXCEPT : m_val(0), m_cat(&generic_category()) {}
-      error_condition( int val, const error_category & cat ) BOOST_SYSTEM_NOEXCEPT
+      BOOST_SYSTEM_CONSTEXPR error_condition() BOOST_SYSTEM_NOEXCEPT : m_val(0), m_cat(&generic_category()) {}
+      BOOST_SYSTEM_CONSTEXPR error_condition( int val, const error_category & cat ) BOOST_SYSTEM_NOEXCEPT
         : m_val(val), m_cat(&cat) {}
 
       template <class ErrorConditionEnum>
@@ -362,7 +532,7 @@ namespace boost
 
       // modifiers:
 
-      void assign( int val, const error_category & cat ) BOOST_SYSTEM_NOEXCEPT
+      BOOST_SYSTEM_CONSTEXPR void assign( int val, const error_category & cat ) BOOST_SYSTEM_NOEXCEPT
       {
         m_val = val;
         m_cat = &cat;
@@ -377,20 +547,20 @@ namespace boost
         return *this;
       }
 
-      void clear() BOOST_SYSTEM_NOEXCEPT
+      BOOST_SYSTEM_CONSTEXPR void clear() BOOST_SYSTEM_NOEXCEPT
       {
         m_val = 0;
         m_cat = &generic_category();
       }
 
       // observers:
-      int                     value() const BOOST_SYSTEM_NOEXCEPT    { return m_val; }
-      const error_category &  category() const BOOST_SYSTEM_NOEXCEPT { return *m_cat; }
+      BOOST_SYSTEM_CONSTEXPR int                     value() const BOOST_SYSTEM_NOEXCEPT    { return m_val; }
+      BOOST_SYSTEM_CONSTEXPR const error_category &  category() const BOOST_SYSTEM_NOEXCEPT { return *m_cat; }
       std::string             message() const  { return m_cat->message(value()); }
 
 #if !defined(BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS)
 
-      explicit operator bool() const BOOST_SYSTEM_NOEXCEPT  // true if error
+      BOOST_SYSTEM_CONSTEXPR explicit operator bool() const BOOST_SYSTEM_NOEXCEPT  // true if error
       {
         return m_val != 0;
       }
@@ -400,12 +570,12 @@ namespace boost
       typedef void (*unspecified_bool_type)();
       static void unspecified_bool_true() {}
 
-      operator unspecified_bool_type() const BOOST_SYSTEM_NOEXCEPT  // true if error
+      BOOST_SYSTEM_CONSTEXPR operator unspecified_bool_type() const BOOST_SYSTEM_NOEXCEPT  // true if error
       {
         return m_val == 0 ? 0 : unspecified_bool_true;
       }
 
-      bool operator!() const BOOST_SYSTEM_NOEXCEPT  // true if no error
+      BOOST_SYSTEM_CONSTEXPR bool operator!() const BOOST_SYSTEM_NOEXCEPT  // true if no error
       {
         return m_val == 0;
       }
@@ -415,7 +585,7 @@ namespace boost
       // relationals:
       //  the more symmetrical non-member syntax allows enum
       //  conversions work for both rhs and lhs.
-      inline friend bool operator==( const error_condition & lhs,
+      BOOST_SYSTEM_CONSTEXPR inline friend bool operator==( const error_condition & lhs,
                                      const error_condition & rhs ) BOOST_SYSTEM_NOEXCEPT
       {
         return lhs.m_cat == rhs.m_cat && lhs.m_val == rhs.m_val;
@@ -458,8 +628,8 @@ namespace boost
     public:
 
       // constructors:
-      error_code() BOOST_SYSTEM_NOEXCEPT : m_val(0), m_cat(&system_category()) {}
-      error_code( int val, const error_category & cat ) BOOST_SYSTEM_NOEXCEPT
+      BOOST_SYSTEM_CONSTEXPR error_code() BOOST_SYSTEM_NOEXCEPT : m_val(0), m_cat(&system_category()) {}
+      BOOST_SYSTEM_CONSTEXPR error_code( int val, const error_category & cat ) BOOST_SYSTEM_NOEXCEPT
         : m_val(val), m_cat(&cat) {}
 
       template <class ErrorCodeEnum>
@@ -471,7 +641,7 @@ namespace boost
       }
 
       // modifiers:
-      void assign( int val, const error_category & cat ) BOOST_SYSTEM_NOEXCEPT
+      BOOST_SYSTEM_CONSTEXPR void assign( int val, const error_category & cat ) BOOST_SYSTEM_NOEXCEPT
       {
         m_val = val;
         m_cat = &cat;
@@ -485,22 +655,22 @@ namespace boost
         return *this;
       }
 
-      void clear() BOOST_SYSTEM_NOEXCEPT
+      BOOST_SYSTEM_CONSTEXPR void clear() BOOST_SYSTEM_NOEXCEPT
       {
         m_val = 0;
         m_cat = &system_category();
       }
 
       // observers:
-      int                     value() const  BOOST_SYSTEM_NOEXCEPT   { return m_val; }
-      const error_category &  category() const BOOST_SYSTEM_NOEXCEPT { return *m_cat; }
+      BOOST_SYSTEM_CONSTEXPR int                     value() const  BOOST_SYSTEM_NOEXCEPT   { return m_val; }
+      BOOST_SYSTEM_CONSTEXPR const error_category &  category() const BOOST_SYSTEM_NOEXCEPT { return *m_cat; }
       error_condition         default_error_condition() const BOOST_SYSTEM_NOEXCEPT
         { return m_cat->default_error_condition(value()); }
       std::string             message() const  { return m_cat->message(value()); }
 
 #if !defined(BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS)
 
-      explicit operator bool() const BOOST_SYSTEM_NOEXCEPT  // true if error
+      BOOST_SYSTEM_CONSTEXPR explicit operator bool() const BOOST_SYSTEM_NOEXCEPT  // true if error
       {
         return m_val != 0;
       }
@@ -510,12 +680,12 @@ namespace boost
       typedef void (*unspecified_bool_type)();
       static void unspecified_bool_true() {}
 
-      operator unspecified_bool_type() const  BOOST_SYSTEM_NOEXCEPT // true if error
+      BOOST_SYSTEM_CONSTEXPR operator unspecified_bool_type() const  BOOST_SYSTEM_NOEXCEPT // true if error
       {
         return m_val == 0 ? 0 : unspecified_bool_true;
       }
 
-      bool operator!() const  BOOST_SYSTEM_NOEXCEPT // true if no error
+      BOOST_SYSTEM_CONSTEXPR bool operator!() const  BOOST_SYSTEM_NOEXCEPT // true if no error
       {
         return m_val == 0;
       }
@@ -523,7 +693,7 @@ namespace boost
 #endif
 
       // relationals:
-      inline friend bool operator==( const error_code & lhs,
+      BOOST_SYSTEM_CONSTEXPR inline friend bool operator==( const error_code & lhs,
                                      const error_code & rhs ) BOOST_SYSTEM_NOEXCEPT
         //  the more symmetrical non-member syntax allows enum
         //  conversions work for both rhs and lhs.
@@ -596,13 +766,13 @@ namespace boost
   {
     //  non-member functions  ------------------------------------------------//
 
-    inline bool operator!=( const error_code & lhs,
+    BOOST_SYSTEM_CONSTEXPR inline bool operator!=( const error_code & lhs,
                             const error_code & rhs ) BOOST_SYSTEM_NOEXCEPT
     {
       return !(lhs == rhs);
     }
 
-    inline bool operator!=( const error_condition & lhs,
+    BOOST_SYSTEM_CONSTEXPR inline bool operator!=( const error_condition & lhs,
                             const error_condition & rhs ) BOOST_SYSTEM_NOEXCEPT
     {
       return !(lhs == rhs);

test/Jamfile.v2

@@ -76,11 +76,12 @@ project
       return $(result) ;
    }
 
-if [ os.environ UBSAN ]
+if [ os.environ UBSAN ] || [ os.environ CLANG_WIN ]
 {
    rule system-run ( sources + )
    {
       # The 03/11 tests are ODR violations, no point running them under -fsanitize=undefined
+      # Clang on Windows uses MSVC headers, which don't parse under 03/11
       return [ system-run- $(sources) ] ;
    }
 }
@@ -126,6 +127,7 @@ else
          [ run single_instance_test.cpp single_instance_lib1 single_instance_lib2 : : : <link>shared : single_instance_lib_shared ]
          [ system-run before_main_test.cpp ]
          [ run-fail throws_assign_fail.cpp ]
+         [ system-run- constexpr_test.cpp ]
          ;
 
 # Quick (CI) test

test/constexpr_test.cpp

@@ -0,0 +1,68 @@
+
+// Copyright 2018 Peter Dimov.
+// Distributed under the Boost Software License, Version 1.0.
+
+#include <boost/system/error_code.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/config/pragma_message.hpp>
+#include <boost/static_assert.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+
+#if !defined(BOOST_SYSTEM_HAS_CONSTEXPR)
+
+BOOST_PRAGMA_MESSAGE("Skipping constexpr test, BOOST_SYSTEM_HAS_CONSTEXPR isn't defined")
+int main() {}
+
+#else
+
+using namespace boost::system;
+
+constexpr error_code e1( 1, system_category() );
+
+BOOST_STATIC_ASSERT( e1.value() == 1 );
+BOOST_STATIC_ASSERT( e1.category() == system_category() );
+BOOST_STATIC_ASSERT( e1 );
+BOOST_STATIC_ASSERT( e1 == e1 );
+
+constexpr error_code e2( 2, generic_category() );
+
+BOOST_STATIC_ASSERT( e2.value() == 2 );
+BOOST_STATIC_ASSERT( e2.category() == generic_category() );
+BOOST_STATIC_ASSERT( e2 );
+BOOST_STATIC_ASSERT( e2 == e2 );
+
+#if !BOOST_WORKAROUND(BOOST_GCC, < 80200)
+
+BOOST_STATIC_ASSERT( e1 != e2 );
+
+#endif
+
+constexpr error_code e3;
+
+BOOST_STATIC_ASSERT( e3.value() == 0 );
+BOOST_STATIC_ASSERT( e3.category() == system_category() );
+BOOST_STATIC_ASSERT( !e3 );
+BOOST_STATIC_ASSERT( e3 == e3 );
+
+#if !BOOST_WORKAROUND(BOOST_GCC, < 80200)
+
+BOOST_STATIC_ASSERT( e1 != e3 );
+
+#endif
+
+int main()
+{
+    error_code e1_( 1, system_category() );
+    BOOST_TEST_EQ( e1, e1_ );
+
+    error_code e2_( 2, generic_category() );
+    BOOST_TEST_EQ( e2, e2_ );
+
+    error_code e3_;
+    BOOST_TEST_EQ( e3, e3_ );
+
+    return boost::report_errors();
+}
+
+#endif

test/std_mismatch_test.cpp

@@ -38,7 +38,6 @@ static void test_generic_category()
     std::error_category const & st = bt;
 
     BOOST_TEST_CSTR_EQ( bt.name(), st.name() );
-    BOOST_TEST_EQ( bt.name(), st.name() );
 }
 
 static void test_system_category()
@@ -47,7 +46,6 @@ static void test_system_category()
     std::error_category const & st = bt;
 
     BOOST_TEST_CSTR_EQ( bt.name(), st.name() );
-    BOOST_TEST_EQ( bt.name(), st.name() );
 }
 
 int main()