Document BOOST_TEST_TRAIT_SAME

Travis CI shows linking errors on Linux and OS X when __cxa_uncaught_exceptions
is used to implement uncaught_exceptions. There's probably some library missing,
which should be linked in implicitly by the compiler, or the library indeed
does not export the symbol. In any case, __cxa_get_globals-based implementation
should provide the same effect.

.travis.yml

@@ -240,6 +240,7 @@ matrix:
         apt:
           packages:
             - libc++-dev
+            - libc++abi-dev
 
     - os: linux
       compiler: clang++-libc++
@@ -248,10 +249,27 @@ matrix:
         apt:
           packages:
             - libc++-dev
+            - libc++abi-dev
 
     - os: osx
       compiler: clang++
       env: TOOLSET=clang COMPILER=clang++ CXXSTD=03,11,14,1z
+      osx_image: xcode7.3
+
+    - os: osx
+      compiler: clang++
+      env: TOOLSET=clang COMPILER=clang++ CXXSTD=03,11,14,1z
+      osx_image: xcode8.3
+
+    - os: osx
+      compiler: clang++
+      env: TOOLSET=clang COMPILER=clang++ CXXSTD=03,11,14,1z
+      osx_image: xcode9.4
+
+    - os: osx
+      compiler: clang++
+      env: TOOLSET=clang COMPILER=clang++ CXXSTD=03,11,14,1z
+      osx_image: xcode10.1
 
     - os: linux
       compiler: g++

doc/lightweight_test.qbk

@@ -1,7 +1,7 @@
 [/
   Copyright 2010, 2011 Beman Dawes
   Copyright 2013 Ion Gaztanaga
-  Copyright 2014, 2017 Peter Dimov
+  Copyright 2014-2019 Peter Dimov
   Copyright 2017 Kohei Takahashi
 
   Distributed under the Boost Software License, Version 1.0.
@@ -253,6 +253,7 @@ return a boolean value.
 ``
 #define BOOST_TEST_TRAIT_TRUE((Trait)) /*unspecified*/
 #define BOOST_TEST_TRAIT_FALSE((Trait)) /*unspecified*/
+#define BOOST_TEST_TRAIT_SAME(Type1, Type2) /*unspecified*/
 ``
 
 [endsect]
@@ -280,6 +281,20 @@ message containing `Trait`. Note the double set of parentheses.
 
 [endsect]
 
+[section BOOST_TEST_TRAIT_SAME]
+
+``
+BOOST_TEST_TRAIT_SAME(Type1, Type2)
+``
+
+If the two types are not the same, increases the error count and outputs a
+message containing them. This macro requires that the compiler supports
+variadic macros and `__VA_ARGS__`. (Note that unlike `BOOST_TEST_TRAIT_TRUE`
+and `BOOST_TEST_TRAIT_FALSE`, this macro only requires a single set of
+parentheses.)
+
+[endsect]
+
 [section Example]
 
 ``
@@ -297,6 +312,8 @@ int main()
 {
     BOOST_TEST_TRAIT_TRUE(( is_same<X<int, long>::type, int> ));
 
+    BOOST_TEST_TRAIT_SAME( X<int, long>::type, int );
+
     return boost::report_errors();
 }
 ``

include/boost/core/checked_delete.hpp

@@ -7,6 +7,8 @@
 # pragma once
 #endif
 
+#include <boost/config.hpp>
+
 //
 //  boost/checked_delete.hpp
 //
@@ -26,7 +28,7 @@ namespace boost
 
 // verify that types are complete for increased safety
 
-template<class T> inline void checked_delete(T * x)
+template<class T> inline void checked_delete(T * x) BOOST_NOEXCEPT
 {
     // intentionally complex - simplification causes regressions
     typedef char type_must_be_complete[ sizeof(T)? 1: -1 ];
@@ -34,7 +36,7 @@ template<class T> inline void checked_delete(T * x)
     delete x;
 }
 
-template<class T> inline void checked_array_delete(T * x)
+template<class T> inline void checked_array_delete(T * x) BOOST_NOEXCEPT
 {
     typedef char type_must_be_complete[ sizeof(T)? 1: -1 ];
     (void) sizeof(type_must_be_complete);
@@ -46,7 +48,7 @@ template<class T> struct checked_deleter
     typedef void result_type;
     typedef T * argument_type;
 
-    void operator()(T * x) const
+    void operator()(T * x) const BOOST_NOEXCEPT
     {
         // boost:: disables ADL
         boost::checked_delete(x);
@@ -58,7 +60,7 @@ template<class T> struct checked_array_deleter
     typedef void result_type;
     typedef T * argument_type;
 
-    void operator()(T * x) const
+    void operator()(T * x) const BOOST_NOEXCEPT
     {
         boost::checked_array_delete(x);
     }

include/boost/core/lightweight_test_trait.hpp

@@ -9,7 +9,7 @@
 
 // boost/core/lightweight_test_trait.hpp
 //
-// BOOST_TEST_TRAIT_TRUE, BOOST_TEST_TRAIT_FALSE
+// BOOST_TEST_TRAIT_TRUE, BOOST_TEST_TRAIT_FALSE, BOOST_TEST_TRAIT_SAME
 //
 // Copyright 2014 Peter Dimov
 //
@@ -19,6 +19,7 @@
 
 #include <boost/core/lightweight_test.hpp>
 #include <boost/core/typeinfo.hpp>
+#include <boost/core/is_same.hpp>
 
 namespace boost
 {
@@ -46,11 +47,37 @@ template< class T > inline void test_trait_impl( char const * trait, void (*)( T
     }
 }
 
+template<class T> inline bool test_trait_same_impl_( T )
+{
+    return T::value;
+}
+
+template<class T1, class T2> inline void test_trait_same_impl( char const * types,
+  boost::core::is_same<T1, T2> same, char const * file, int line, char const * function )
+{
+    if( test_trait_same_impl_( same ) )
+    {
+        test_results();
+    }
+    else
+    {
+        BOOST_LIGHTWEIGHT_TEST_OSTREAM
+            << file << "(" << line << "): test 'is_same<" << types << ">'"
+            << " failed in function '" << function
+            << "' ('" << boost::core::demangled_name( BOOST_CORE_TYPEID(T1) )
+            << "' != '" << boost::core::demangled_name( BOOST_CORE_TYPEID(T2) ) << "')"
+            << std::endl;
+
+        ++test_results().errors();
+    }
+}
+
 } // namespace detail
 
 } // namespace boost
 
 #define BOOST_TEST_TRAIT_TRUE(type) ( ::boost::detail::test_trait_impl(#type, (void(*)type)0, true, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION) )
 #define BOOST_TEST_TRAIT_FALSE(type) ( ::boost::detail::test_trait_impl(#type, (void(*)type)0, false, __FILE__, __LINE__, BOOST_CURRENT_FUNCTION) )
+#define BOOST_TEST_TRAIT_SAME(...) ( ::boost::detail::test_trait_same_impl(#__VA_ARGS__, ::boost::core::is_same<__VA_ARGS__>(), __FILE__, __LINE__, BOOST_CURRENT_FUNCTION) )
 
 #endif // #ifndef BOOST_CORE_LIGHTWEIGHT_TEST_TRAIT_HPP

include/boost/core/uncaught_exceptions.hpp

@@ -46,20 +46,36 @@
 #if defined(BOOST_CORE_HAS_CXXABI_H)
 // MinGW GCC 4.4 seem to not work the same way the newer GCC versions do. As a result, __cxa_get_globals based implementation will always return 0.
 // Just disable it for now and fall back to std::uncaught_exception().
-#if !defined(__MINGW32__) || (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)))
-#define BOOST_CORE_HAS_CXA_GET_GLOBALS
+#if !(defined(__MINGW32__) && (defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__) < 405))
 #include <cxxabi.h>
-// Only GCC 4.7 declares __cxa_get_globals() in cxxabi.h, older compilers do not expose this function but it's there
-#if defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__) < 407
+#include <cstring>
+#define BOOST_CORE_HAS_CXA_GET_GLOBALS
+// At least on MinGW and Linux, only GCC since 4.7 declares __cxa_get_globals() in cxxabi.h. Older versions of GCC do not expose this function but it's there.
+// On OpenBSD, it seems, the declaration is also missing.
+// Note that at least on FreeBSD 11, cxxabi.h declares __cxa_get_globals with a different exception specification, so we can't declare the function unconditionally.
+// On Linux with clang and libc++ and on OS X, there is a version of cxxabi.h from libc++abi that doesn't declare __cxa_get_globals, but provides __cxa_uncaught_exceptions.
+// The function only appeared in version _LIBCPPABI_VERSION >= 1002 of the library. Unfortunately, there are linking errors about undefined reference to __cxa_uncaught_exceptions
+// on Ubuntu Trusty and OS X, so we avoid using it and forward-declare __cxa_get_globals instead.
+#if !defined(__FreeBSD__) && \
+    ( \
+        (defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__) < 407) || \
+        defined(__OpenBSD__) || \
+        defined(_LIBCPPABI_VERSION) \
+    )
 namespace __cxxabiv1 {
 struct __cxa_eh_globals;
+#if defined(__OpenBSD__)
+extern "C" __cxa_eh_globals* __cxa_get_globals();
+#else
 extern "C" __cxa_eh_globals* __cxa_get_globals() BOOST_NOEXCEPT_OR_NOTHROW __attribute__((__const__));
-} // namespace __cxxabiv1
-#endif // defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__) < 407
 #endif
+} // namespace __cxxabiv1
+#endif
+#endif // !(defined(__MINGW32__) && (defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__) < 405))
 #endif // defined(BOOST_CORE_HAS_CXXABI_H)
 
 #if defined(_MSC_VER) && _MSC_VER >= 1400
+#include <cstring>
 #define BOOST_CORE_HAS_GETPTD
 namespace boost {
 namespace core {
@@ -89,10 +105,14 @@ inline unsigned int uncaught_exceptions() BOOST_NOEXCEPT
     return static_cast< unsigned int >(std::uncaught_exceptions());
 #elif defined(BOOST_CORE_HAS_CXA_GET_GLOBALS)
     // Tested on {clang 3.2,GCC 3.5.6,GCC 4.1.2,GCC 4.4.6,GCC 4.4.7}x{x32,x64}
-    return *(reinterpret_cast< const unsigned int* >(reinterpret_cast< const char* >(::abi::__cxa_get_globals()) + sizeof(void*))); // __cxa_eh_globals::uncaughtExceptions, x32 offset - 0x4, x64 - 0x8
+    unsigned int count;
+    std::memcpy(&count, reinterpret_cast< const unsigned char* >(::abi::__cxa_get_globals()) + sizeof(void*), sizeof(count)); // __cxa_eh_globals::uncaughtExceptions, x32 offset - 0x4, x64 - 0x8
+    return count;
 #elif defined(BOOST_CORE_HAS_GETPTD)
     // MSVC specific. Tested on {MSVC2005SP1,MSVC2008SP1,MSVC2010SP1,MSVC2012}x{x32,x64}.
-    return *(reinterpret_cast< const unsigned int* >(static_cast< const char* >(boost::core::detail::_getptd()) + (sizeof(void*) == 8 ? 0x100 : 0x90))); // _tiddata::_ProcessingThrow, x32 offset - 0x90, x64 - 0x100
+    unsigned int count;
+    std::memcpy(&count, static_cast< const unsigned char* >(boost::core::detail::_getptd()) + (sizeof(void*) == 8u ? 0x100 : 0x90), sizeof(count)); // _tiddata::_ProcessingThrow, x32 offset - 0x90, x64 - 0x100
+    return count;
 #else
     // Portable C++03 implementation. Does not allow to detect multiple nested exceptions.
     return static_cast< unsigned int >(std::uncaught_exception());

test/Jamfile.v2

@@ -76,6 +76,8 @@ run lightweight_test_lt_le_test.cpp ;
 run lightweight_test_gt_ge_test.cpp ;
 run lightweight_test_eq_nullptr.cpp ;
 run lightweight_test_test3.cpp ;
+run lightweight_test_test4.cpp ;
+run lightweight_test_test5.cpp ;
 
 run-fail lightweight_test_fail.cpp ;
 run-fail lightweight_test_fail2.cpp ;

test/lightweight_test_test4.cpp

@@ -0,0 +1,36 @@
+//
+// Test for BOOST_TEST_TRAIT_SAME
+//
+// Copyright 2014, 2019 Peter Dimov
+//
+// Distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt
+//
+
+#include <boost/core/lightweight_test_trait.hpp>
+
+struct X
+{
+    typedef int type;
+};
+
+template<class T1, class T2> struct Y
+{
+    typedef T1 type;
+};
+
+int main()
+{
+    BOOST_TEST_TRAIT_SAME(X, X);
+    BOOST_TEST_TRAIT_SAME(void, void);
+    BOOST_TEST_TRAIT_SAME(char[1], char[1]);
+    BOOST_TEST_TRAIT_SAME(char[], char[]);
+    BOOST_TEST_TRAIT_SAME(void(), void());
+    BOOST_TEST_TRAIT_SAME(X::type, X::type);
+    BOOST_TEST_TRAIT_SAME(X::type, Y<int, float>::type);
+    BOOST_TEST_TRAIT_SAME(Y<int, float>, Y<int, float>);
+    BOOST_TEST_TRAIT_SAME(Y<void, float>::type, void);
+
+    return boost::report_errors();
+}

test/lightweight_test_test5.cpp

@@ -0,0 +1,37 @@
+//
+// Negative test for BOOST_TEST_TRAIT_SAME
+//
+// Copyright 2014, 2019 Peter Dimov
+//
+// Distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt
+//
+
+#include <boost/core/lightweight_test_trait.hpp>
+
+struct X
+{
+    typedef int type;
+};
+
+template<class T1, class T2> struct Y
+{
+    typedef T1 type;
+};
+
+int main()
+{
+    BOOST_TEST_TRAIT_SAME(char[1], char[2]);
+    BOOST_TEST_TRAIT_SAME(char[1], char[]);
+    BOOST_TEST_TRAIT_SAME(char[1], char*);
+    BOOST_TEST_TRAIT_SAME(void(), void(int));
+    BOOST_TEST_TRAIT_SAME(void(), void(*)());
+    BOOST_TEST_TRAIT_SAME(X, void);
+    BOOST_TEST_TRAIT_SAME(X::type, void);
+    BOOST_TEST_TRAIT_SAME(X, Y<void, void>);
+    BOOST_TEST_TRAIT_SAME(X::type, Y<float, int>::type);
+    BOOST_TEST_TRAIT_SAME(Y<int, float>, Y<int, double>);
+
+    return boost::report_errors() == 10;
+}