Add .github/workflows

libc++ disables std::uncaught_exceptions for Mac OS < 10.12 and
iOS < 10.0, even though it defines __cpp_lib_uncaught_exceptions.

Fixes https://github.com/boostorg/core/issues/80.

.github/workflows/posix.yml

@@ -0,0 +1,84 @@
+name: POSIX
+
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+      - develop
+      - feature/**
+
+env:
+  LIBRARY: core
+  UBSAN_OPTIONS: print_stacktrace=1
+
+jobs:
+  CI:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - toolset: gcc-4.7
+            cxxstd: "03,11"
+            os: ubuntu-16.04
+            install: g++-4.7
+          - toolset: gcc-4.8
+            cxxstd: "03,11"
+            os: ubuntu-16.04
+            install: g++-4.8
+          - toolset: gcc-4.9
+            cxxstd: "03,11"
+            os: ubuntu-16.04
+            install: g++-4.9
+          - toolset: gcc-5
+            cxxstd: "03,11,14,1z"
+            os: ubuntu-16.04
+          - toolset: gcc-6
+            cxxstd: "03,11,14,1z"
+            os: ubuntu-16.04
+            install: g++-6
+          - toolset: gcc-7
+            cxxstd: "03,11,14,17"
+            os: ubuntu-18.04
+          - toolset: gcc-8
+            cxxstd: "03,11,14,17,2a"
+            os: ubuntu-18.04
+          - toolset: gcc-9
+            cxxstd: "03,11,14,17,2a"
+            os: ubuntu-18.04
+          - toolset: gcc-10
+            cxxstd: "03,11,14,17,2a"
+            os: ubuntu-18.04
+          - toolset: clang
+            cxxstd: "03,11,14,17,2a"
+            os: ubuntu-18.04
+          - toolset: clang
+            cxxstd: "03,11,14,17,2a"
+            os: macos-10.15
+
+    runs-on: ${{matrix.os}}
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Install packages
+        if: matrix.install
+        run: sudo apt install ${{matrix.install}}
+
+      - name: Setup Boost
+        run: |
+          REF=${GITHUB_BASE_REF:-$GITHUB_REF}
+          BOOST_BRANCH=develop && [ "$REF" == "master" ] && BOOST_BRANCH=master || true
+          cd ..
+          git clone -b $BOOST_BRANCH --depth 1 https://github.com/boostorg/boost.git boost-root
+          cd boost-root
+          cp -r $GITHUB_WORKSPACE/* libs/$LIBRARY
+          git submodule update --init tools/boostdep
+          python tools/boostdep/depinst/depinst.py --git_args "--jobs 3" $LIBRARY
+          ./bootstrap.sh
+          ./b2 -d0 headers
+
+      - name: Run tests
+        run: |
+          cd ../boost-root
+          ./b2 -j3 libs/$LIBRARY/test toolset=${{matrix.toolset}} cxxstd=${{matrix.cxxstd}} variant=debug,release

.github/workflows/windows.yml

@@ -0,0 +1,51 @@
+name: Windows
+
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+      - develop
+      - feature/**
+
+env:
+  LIBRARY: core
+
+jobs:
+  CI:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - toolset: msvc-14.1
+            cxxstd: "14,17,latest"
+            os: windows-2016
+          - toolset: msvc-14.2
+            cxxstd: "14,17,latest"
+            os: windows-2019
+
+    runs-on: ${{matrix.os}}
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Setup Boost
+        shell: cmd
+        run: |
+          if "%GITHUB_BASE_REF%" == "" set GITHUB_BASE_REF=%GITHUB_REF%
+          set BOOST_BRANCH=develop
+          if "%GITHUB_BASE_REF%" == "master" set BOOST_BRANCH=master
+          cd ..
+          git clone -b %BOOST_BRANCH% --depth 1 https://github.com/boostorg/boost.git boost-root
+          cd boost-root
+          xcopy /s /e /q %GITHUB_WORKSPACE% libs\%LIBRARY%\
+          git submodule update --init tools/boostdep
+          python tools/boostdep/depinst/depinst.py --git_args "--jobs 3" %LIBRARY%
+          cmd /c bootstrap
+          b2 -d0 headers
+
+      - name: Run tests
+        shell: cmd
+        run: |
+          cd ../boost-root
+          b2 -j3 libs/%LIBRARY%/test toolset=${{matrix.toolset}} cxxstd=${{matrix.cxxstd}} variant=debug,release address-model=32,64

.travis.yml

@@ -129,7 +129,7 @@ matrix:
     - os: linux
       dist: bionic
       compiler: g++-10
-      env: TOOLSET=gcc COMPILER=g++-10 CXXSTD=03,11,14,17,2a
+      env: TOOLSET=gcc COMPILER=g++-10 CXXSTD=03,11,14,17,20
       addons:
         apt:
           packages:
@@ -140,7 +140,7 @@ matrix:
     - os: linux
       dist: bionic
       compiler: g++-10
-      env: UBSAN=1 TOOLSET=gcc COMPILER=g++-10 CXXSTD=03,11,14,17,2a UBSAN_OPTIONS=print_stacktrace=1 LINKFLAGS=-fuse-ld=gold
+      env: UBSAN=1 TOOLSET=gcc COMPILER=g++-10 CXXSTD=03,11,14,17,20 UBSAN_OPTIONS=print_stacktrace=1 LINKFLAGS=-fuse-ld=gold
       addons:
         apt:
           packages:
@@ -287,7 +287,7 @@ matrix:
 
     - os: linux
       compiler: clang++-10
-      env: TOOLSET=clang COMPILER=clang++-10 CXXSTD=03,11,14,17,2a
+      env: TOOLSET=clang COMPILER=clang++-10 CXXSTD=03,11,14,17,20
       addons:
         apt:
           packages:
@@ -299,7 +299,7 @@ matrix:
 
     - os: linux
       compiler: clang++-10
-      env: UBSAN=1 TOOLSET=clang COMPILER=clang++-10 CXXSTD=03,11,14,17,2a UBSAN_OPTIONS=print_stacktrace=1
+      env: UBSAN=1 TOOLSET=clang COMPILER=clang++-10 CXXSTD=03,11,14,17,20 UBSAN_OPTIONS=print_stacktrace=1
       addons:
         apt:
           packages:

appveyor.yml

@@ -16,6 +16,7 @@ environment:
   matrix:
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
       TOOLSET: msvc-9.0,msvc-10.0,msvc-11.0
+      ADDRMD: 32
 
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
       TOOLSET: msvc-12.0,msvc-14.0
@@ -36,7 +37,7 @@ environment:
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
       TOOLSET: msvc-14.2
       ADDRMD: 32,64
-      CXXSTD: 14,17
+      CXXSTD: 14,17,latest
 
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
       ADDPATH: C:\cygwin\bin;

include/boost/core/allocator_access.hpp

@@ -137,6 +137,11 @@ template<class A>
 struct allocator_difference_type {
     typedef typename A::difference_type type;
 };
+#elif defined(BOOST_MSVC)
+template<class A>
+struct allocator_difference_type {
+    typedef typename std::allocator_traits<A>::difference_type type;
+};
 #else
 template<class A, class = void>
 struct allocator_difference_type {
@@ -156,6 +161,11 @@ template<class A>
 struct allocator_size_type {
     typedef typename A::size_type type;
 };
+#elif defined(BOOST_MSVC)
+template<class A>
+struct allocator_size_type {
+    typedef typename std::allocator_traits<A>::size_type type;
+};
 #else
 template<class A, class = void>
 struct allocator_size_type {

include/boost/core/ref.hpp

@@ -10,6 +10,7 @@
 #include <boost/config.hpp>
 #include <boost/config/workaround.hpp>
 #include <boost/core/addressof.hpp>
+#include <boost/core/enable_if.hpp>
 
 //
 //  ref.hpp - ref/cref, useful helper functions
@@ -46,6 +47,26 @@ namespace boost
 
 #endif
 
+namespace detail
+{
+
+template< class Y, class T > struct ref_convertible
+{
+    typedef char (&yes) [1];
+    typedef char (&no)  [2];
+
+    static yes f( T* );
+    static no  f( ... );
+
+    enum _vt { value = sizeof( (f)( static_cast<Y*>(0) ) ) == sizeof(yes) };
+};
+
+struct ref_empty
+{
+};
+
+} // namespace detail
+
 // reference_wrapper
 
 /**
@@ -87,6 +108,14 @@ public:
 public:
 #endif
 
+    template<class Y> friend class reference_wrapper;
+
+    template<class Y> reference_wrapper( reference_wrapper<Y> r,
+        typename enable_if_c<boost::detail::ref_convertible<Y, T>::value,
+            boost::detail::ref_empty>::type = boost::detail::ref_empty() ): t_( r.t_ )
+    {
+    }
+
     /**
      @return The stored reference.
      @remark Does not throw.

include/boost/core/uncaught_exceptions.hpp

@@ -1,5 +1,5 @@
 /*
- *             Copyright Andrey Semashev 2018.
+ *          Copyright Andrey Semashev 2018 - 2020.
  * Distributed under the Boost Software License, Version 1.0.
  *    (See accompanying file LICENSE_1_0.txt or copy at
  *          https://www.boost.org/LICENSE_1_0.txt)
@@ -26,8 +26,23 @@
 #pragma once
 #endif
 
-// Visual Studio 14 supports N4152 std::uncaught_exceptions()
-#if (defined(__cpp_lib_uncaught_exceptions) && __cpp_lib_uncaught_exceptions >= 201411) || \
+#if defined(__APPLE__)
+#include <Availability.h>
+// Apple systems only support std::uncaught_exceptions starting with specific versions:
+// - Mac OS >= 10.12
+// - iOS >= 10.0
+// - tvOS >= 10.0
+// - watchOS >= 3.0
+// https://github.com/boostorg/core/issues/80
+#if (defined(__cpp_lib_uncaught_exceptions) && __cpp_lib_uncaught_exceptions >= 201411) && \
+    ( \
+        (defined(__MAC_OS_X_VERSION_MIN_REQUIRED) && __MAC_OS_X_VERSION_MIN_REQUIRED >= 101200) || \
+        (defined(__IPHONE_OS_VERSION_MIN_REQUIRED) && __IPHONE_OS_VERSION_MIN_REQUIRED >= 100000) \
+    )
+#define BOOST_CORE_HAS_UNCAUGHT_EXCEPTIONS
+#endif
+// Visual Studio 14.0 supports N4152 std::uncaught_exceptions() but doesn't define __cpp_lib_uncaught_exceptions
+#elif (defined(__cpp_lib_uncaught_exceptions) && __cpp_lib_uncaught_exceptions >= 201411) || \
     (defined(_MSC_VER) && _MSC_VER >= 1900)
 #define BOOST_CORE_HAS_UNCAUGHT_EXCEPTIONS
 #endif
@@ -46,7 +61,11 @@
 #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__ * 100 + __GNUC_MINOR__) < 405))
+// On AIX, xlclang++ does have cxxabi.h but doesn't have __cxa_get_globals (https://github.com/boostorg/core/issues/78).
+#if !( \
+        (defined(__MINGW32__) && (defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__) < 405)) || \
+        defined(__ibmxl__) \
+    )
 #include <cxxabi.h>
 #include <cstring>
 #define BOOST_CORE_HAS_CXA_GET_GLOBALS
@@ -76,7 +95,7 @@ extern "C" __cxa_eh_globals* __cxa_get_globals() BOOST_NOEXCEPT_OR_NOTHROW __att
 #endif
 } // namespace __cxxabiv1
 #endif
-#endif // !(defined(__MINGW32__) && (defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__) < 405))
+#endif
 #endif // defined(BOOST_CORE_HAS_CXXABI_H)
 
 #if defined(_MSC_VER) && _MSC_VER >= 1400

test/Jamfile.v2

@@ -35,7 +35,10 @@ compile-fail ref_rv_fail4.cpp ;
 compile-fail ref_rv_fail5.cpp ;
 compile-fail ref_implicit_fail.cpp ;
 compile-fail ref_implicit_fail2.cpp ;
+compile-fail ref_implicit_fail3.cpp ;
+compile-fail ref_implicit_fail4.cpp ;
 run ref_cv_test.cpp ;
+run ref_conversion_test.cpp ;
 
 run eif_constructors.cpp ;
 run eif_dummy_arg_disambiguation.cpp ;

test/lightweight_test_with_fail.cpp

@@ -13,17 +13,17 @@ template <typename T>
 struct with_tolerance
 {
     with_tolerance( T tolerance ): tolerance( tolerance )
-	{
-	}
+    {
+    }
 
-	bool operator()( T lhs, T rhs ) const
+    bool operator()( T lhs, T rhs ) const
     {
         return std::abs( lhs - rhs ) <= tolerance;
     }
 
 private:
 
-	T tolerance;
+    T tolerance;
 };
 
 void test_tolerance_predicate()

test/ref_conversion_test.cpp

@@ -0,0 +1,39 @@
+//  Implicit conversions between compatible reference wrappers
+//
+//  Copyright 2020 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/ref.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+struct X
+{
+};
+
+struct Y: public X
+{
+};
+
+void f1( boost::reference_wrapper<X> r, Y * p )
+{
+    BOOST_TEST_EQ( r.get_pointer(), p );
+}
+
+void f2( boost::reference_wrapper<int const> r, int * p )
+{
+    BOOST_TEST_EQ( r.get_pointer(), p );
+}
+
+int main()
+{
+    Y y;
+    f1( boost::ref(y), &y );
+
+    int i = 0;
+    f2( boost::ref(i), &i );
+
+    return boost::report_errors();
+}

test/ref_implicit_fail3.cpp

@@ -0,0 +1,29 @@
+//
+// Incompatible reference_wrappers must not implicitly convert to each other
+//
+// Copyright 2020 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/ref.hpp>
+
+struct X
+{
+};
+
+struct Y
+{
+};
+
+void f( boost::reference_wrapper<X> )
+{
+}
+
+int main()
+{
+    Y y;
+    f( boost::ref(y) ); // should fail
+}

test/ref_implicit_fail4.cpp

@@ -0,0 +1,21 @@
+//
+// Incompatible reference_wrappers must not implicitly convert to each other
+//
+// Copyright 2020 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/ref.hpp>
+
+void f( boost::reference_wrapper< int const > )
+{
+}
+
+int main()
+{
+    long y = 0;
+    f( boost::ref(y) ); // should fail
+}