Update documentation

.drone.jsonnet

@@ -235,6 +235,76 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
         "clang-3.8",
     ),
 
+    linux_pipeline(
+        "Linux 18.04 Clang 3.9",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-3.9', CXXSTD: '03,11,14' },
+        "clang-3.9",
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 Clang 4.0",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-4.0', CXXSTD: '03,11,14' },
+        "clang-4.0",
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 Clang 5.0",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-5.0', CXXSTD: '03,11,14,1z' },
+        "clang-5.0",
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 Clang 6.0",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-6.0', CXXSTD: '03,11,14,17' },
+        "clang-6.0",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 7",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-7', CXXSTD: '03,11,14,17' },
+        "clang-7",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 8",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-8', CXXSTD: '03,11,14,17' },
+        "clang-8",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 9",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-9', CXXSTD: '03,11,14,17,2a' },
+        "clang-9",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 10",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-10', CXXSTD: '03,11,14,17,2a' },
+        "clang-10",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 11",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-11', CXXSTD: '03,11,14,17,2a' },
+        "clang-11",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 12",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-12', CXXSTD: '03,11,14,17,2a' },
+        "clang-12",
+    ),
+
     linux_pipeline(
         "Linux 22.04 Clang 13",
         "cppalliance/droneubuntu2204:1",

doc/array/changes.adoc

@@ -21,3 +21,4 @@ http://www.boost.org/LICENSE_1_0.txt
 * Removed local `hash_value` overload; `boost::hash` supports array-like types natively.
 * `array<T, 0>` can now be initialized with `= {{}}`.
 * Added `operator\<\=>`.
+* Added `to_array`.

doc/array/reference.adoc

@@ -42,6 +42,13 @@ namespace boost {
     constexpr T& get(array<T, N>&) noexcept;
   template<std::size_t Idx, typename T, std::size_t N>
     constexpr const T& get(const array<T, N>&) noexcept;
+
+  template<class T, std::size_t N>
+    constexpr array<T, N> to_array( T const (&)[N] );
+  template<class T, std::size_t N>
+    constexpr array<T, N> to_array( T (&&)[N] );
+  template<class T, std::size_t N>
+    constexpr array<T, N> to_array( T const (&&)[N] );
 }
 ```
 
@@ -417,3 +424,29 @@ Mandates: :: `Idx < N`.
 Returns: :: `arr[Idx]`.
 
 ---
+
+
+### Creation
+
+```
+template<class T, std::size_t N>
+  constexpr array<T, N> to_array( T const (&a)[N] );
+```
+[horizontal]
+Returns: :: an `array<T, N>` `r` such that for each `i` in `[0..N)`, `r[i]` is copied from `a[i]`.
+
+```
+template<class T, std::size_t N>
+  constexpr array<T, N> to_array( T (&&a)[N] );
+```
+[horizontal]
+Returns: :: an `array<T, N>` `r` such that for each `i` in `[0..N)`, `r[i]` is moved from `std::move(a[i])`.
+
+```
+template<class T, std::size_t N>
+  constexpr array<T, N> to_array( T const (&&a)[N] );
+```
+[horizontal]
+Returns: :: an `array<T, N>` `r` such that for each `i` in `[0..N)`, `r[i]` is copied from `a[i]`.
+
+---

include/boost/array.hpp

@@ -51,6 +51,12 @@
 #include <utility>
 #include <cstddef>
 
+#if defined(__cpp_impl_three_way_comparison) && __cpp_impl_three_way_comparison >= 201907L
+# if __has_include(<compare>)
+#  include <compare>
+# endif
+#endif
+
 namespace boost {
 
     template<class T, std::size_t N>
@@ -383,6 +389,7 @@ namespace boost {
     }
 
 #if defined(__cpp_impl_three_way_comparison) && __cpp_impl_three_way_comparison >= 201907L
+# if __has_include(<compare>)
 
     template<class T, std::size_t N>
     constexpr auto operator<=> (const array<T,N>& x, const array<T,N>& y)
@@ -394,16 +401,17 @@ namespace boost {
             if( r != 0 ) return r;
         }
 
-        return 0 <=> 0; // std::strong_ordering::equal
+        return std::strong_ordering::equal;
     }
 
     template<class T>
     constexpr auto operator<=> (const array<T,0>& /*x*/, const array<T,0>& /*y*/)
-        -> decltype( 0 <=> 0 )
+        -> std::strong_ordering
     {
-        return 0 <=> 0; // std::strong_ordering::equal
+        return std::strong_ordering::equal;
     }
 
+# endif
 #endif
 
     // undocumented and obsolete
@@ -422,17 +430,62 @@ namespace boost {
         return arg.elems;
     }
 
-   template <size_t Idx, typename T, size_t N>
-   BOOST_CXX14_CONSTEXPR T &get(boost::array<T,N> &arr) BOOST_NOEXCEPT {
-       BOOST_STATIC_ASSERT_MSG ( Idx < N, "boost::get<>(boost::array &) index out of range" );
-       return arr[Idx];
-       }
+    template <size_t Idx, typename T, size_t N>
+    BOOST_CXX14_CONSTEXPR T &get(boost::array<T,N> &arr) BOOST_NOEXCEPT
+    {
+        BOOST_STATIC_ASSERT_MSG ( Idx < N, "boost::get<>(boost::array &) index out of range" );
+        return arr[Idx];
+    }
 
-   template <size_t Idx, typename T, size_t N>
-   BOOST_CONSTEXPR const T &get(const boost::array<T,N> &arr) BOOST_NOEXCEPT {
-       BOOST_STATIC_ASSERT_MSG ( Idx < N, "boost::get<>(const boost::array &) index out of range" );
-       return arr[Idx];
-       }
+    template <size_t Idx, typename T, size_t N>
+    BOOST_CONSTEXPR const T &get(const boost::array<T,N> &arr) BOOST_NOEXCEPT
+    {
+        BOOST_STATIC_ASSERT_MSG ( Idx < N, "boost::get<>(const boost::array &) index out of range" );
+        return arr[Idx];
+    }
+
+    template<class T, std::size_t N>
+    BOOST_CXX14_CONSTEXPR array<T, N> to_array( T const (&a)[ N ] )
+    {
+        array<T, N> r = {};
+
+        for( std::size_t i = 0; i < N; ++i )
+        {
+            r[ i ] = a[ i ];
+        }
+
+        return r;
+    }
+
+#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
+
+    template<class T, std::size_t N>
+    BOOST_CXX14_CONSTEXPR array<T, N> to_array( T (&&a)[ N ] )
+    {
+        array<T, N> r = {};
+
+        for( std::size_t i = 0; i < N; ++i )
+        {
+            r[ i ] = std::move( a[ i ] );
+        }
+
+        return r;
+    }
+
+    template<class T, std::size_t N>
+    BOOST_CXX14_CONSTEXPR array<T, N> to_array( T const (&&a)[ N ] )
+    {
+        array<T, N> r = {};
+
+        for( std::size_t i = 0; i < N; ++i )
+        {
+            r[ i ] = a[ i ];
+        }
+
+        return r;
+    }
+
+#endif
 
 } /* namespace boost */
 

test/Jamfile.v2

@@ -84,6 +84,7 @@ run array_eq_test.cpp ;
 run array_lt_test.cpp ;
 run array_thw_test.cpp ;
 run array_get_test.cpp ;
+run to_array_test.cpp ;
 
 # C++11 constexpr
 
@@ -103,6 +104,7 @@ compile array_fill_test_cx.cpp ;
 compile array_eq_test_cx.cpp ;
 compile array_lt_test_cx.cpp ;
 compile array_thw_test_cx.cpp ;
+compile to_array_test_cx.cpp ;
 
 #
 

test/array_access_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #define BOOST_ENABLE_ASSERT_HANDLER
 

test/array_access_test_cx.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/config.hpp>

test/array_access_test_cx2.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/config.hpp>

test/array_assign_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #define BOOST_ALLOW_DEPRECATED_SYMBOLS
 

test/array_assign_test_cx.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/config.hpp>

test/array_c_array_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #define BOOST_ALLOW_DEPRECATED_SYMBOLS
 

test/array_convert_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/core/lightweight_test.hpp>

test/array_copy_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/core/lightweight_test.hpp>

test/array_copy_test_cx.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/config.hpp>

test/array_data_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/core/lightweight_test.hpp>

test/array_data_test_cx.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/config.hpp>

test/array_elems_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/core/lightweight_test.hpp>

test/array_eq_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/core/lightweight_test.hpp>

test/array_eq_test_cx.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/config.hpp>

test/array_fill_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/core/lightweight_test.hpp>

test/array_fill_test_cx.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/config.hpp>

test/array_get_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/core/lightweight_test.hpp>

test/array_get_test_cx.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/config.hpp>

test/array_init_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/core/lightweight_test.hpp>

test/array_init_test_cx.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/config.hpp>

test/array_iterator_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/core/lightweight_test.hpp>

test/array_iterator_test_cx.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/config.hpp>

test/array_lt_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/core/lightweight_test.hpp>

test/array_lt_test_cx.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/config.hpp>

test/array_reverse_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/core/lightweight_test.hpp>

test/array_size_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/core/lightweight_test.hpp>

test/array_size_test_cx.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/config.hpp>

test/array_swap_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/core/lightweight_test.hpp>

test/array_swap_test2.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/core/lightweight_test.hpp>

test/array_thw_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/core/lightweight_test.hpp>
@@ -8,6 +8,12 @@
 #include <boost/config/pragma_message.hpp>
 #include <cstddef>
 
+#if defined(__has_include)
+# if __has_include(<compare>)
+#  define HAS_COMPARE
+# endif
+#endif
+
 #if !defined(__cpp_impl_three_way_comparison)
 
 BOOST_PRAGMA_MESSAGE( "Test skipped because __cpp_impl_three_way_comparison is not defined" )
@@ -18,6 +24,11 @@ int main() {}
 BOOST_PRAGMA_MESSAGE( "Test skipped because __cpp_impl_three_way_comparison is defined to " BOOST_STRINGIZE(__cpp_impl_three_way_comparison) )
 int main() {}
 
+#elif !defined(HAS_COMPARE)
+
+BOOST_PRAGMA_MESSAGE( "Test skipped because <compare> is not available" )
+int main() {}
+
 #else
 
 template<class T, std::size_t N> void test()

test/array_thw_test_cx.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/config.hpp>
@@ -8,6 +8,12 @@
 #include <boost/config/workaround.hpp>
 #include <cstddef>
 
+#if defined(__has_include)
+# if __has_include(<compare>)
+#  define HAS_COMPARE
+# endif
+#endif
+
 #if !defined(__cpp_impl_three_way_comparison)
 
 BOOST_PRAGMA_MESSAGE( "Test skipped because __cpp_impl_three_way_comparison is not defined" )
@@ -18,6 +24,11 @@ int main() {}
 BOOST_PRAGMA_MESSAGE( "Test skipped because __cpp_impl_three_way_comparison is defined to " BOOST_STRINGIZE(__cpp_impl_three_way_comparison) )
 int main() {}
 
+#elif !defined(HAS_COMPARE)
+
+BOOST_PRAGMA_MESSAGE( "Test skipped because <compare> is not available" )
+int main() {}
+
 #else
 
 #define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)

test/array_typedef_test.cpp

@@ -1,6 +1,6 @@
 // Copyright 2025 Peter Dimov
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 #include <boost/core/lightweight_test_trait.hpp>

test/quick.cpp

@@ -1,6 +1,6 @@
 // Copyright 2023 Peter Dimov.
 // Distributed under the Boost Software License, Version 1.0.
-// https://www.boost.org/LICENSE_1_0.txt)
+// https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/array.hpp>
 

test/to_array_test.cpp

@@ -0,0 +1,109 @@
+// Copyright 2025 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/array.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+#include <memory>
+#include <utility>
+
+boost::array<int, 3> f1()
+{
+    boost::array<int, 3> r = {{ 1, 2, 3 }};
+    return r;
+}
+
+boost::array<int, 3> const f2()
+{
+    boost::array<int, 3> r = {{ 1, 2, 3 }};
+    return r;
+}
+
+int main()
+{
+    {
+        int a[] = { 1, 2, 3 };
+
+        boost::array<int, 3> b = boost::to_array( a );
+
+        BOOST_TEST_EQ( b[0], 1 );
+        BOOST_TEST_EQ( b[1], 2 );
+        BOOST_TEST_EQ( b[2], 3 );
+    }
+
+    {
+        int const a[] = { 1, 2, 3 };
+
+        boost::array<int, 3> b = boost::to_array( a );
+
+        BOOST_TEST_EQ( b[0], 1 );
+        BOOST_TEST_EQ( b[1], 2 );
+        BOOST_TEST_EQ( b[2], 3 );
+    }
+
+    {
+        boost::array<int, 3> b = boost::to_array( f1().elems );
+
+        BOOST_TEST_EQ( b[0], 1 );
+        BOOST_TEST_EQ( b[1], 2 );
+        BOOST_TEST_EQ( b[2], 3 );
+    }
+
+    {
+        boost::array<int, 3> b = boost::to_array( f2().elems );
+
+        BOOST_TEST_EQ( b[0], 1 );
+        BOOST_TEST_EQ( b[1], 2 );
+        BOOST_TEST_EQ( b[2], 3 );
+    }
+
+#if BOOST_CXX_VERSION >= 201103L
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, < 1910)
+    {
+        int a[] = { 1, 2, 3 };
+
+        boost::array<int, 3> b = boost::to_array( std::move( a ) );
+
+        BOOST_TEST_EQ( b[0], 1 );
+        BOOST_TEST_EQ( b[1], 2 );
+        BOOST_TEST_EQ( b[2], 3 );
+    }
+
+    {
+        int const a[] = { 1, 2, 3 };
+
+        boost::array<int, 3> b = boost::to_array( std::move( a ) );
+
+        BOOST_TEST_EQ( b[0], 1 );
+        BOOST_TEST_EQ( b[1], 2 );
+        BOOST_TEST_EQ( b[2], 3 );
+    }
+#endif
+
+#if !BOOST_WORKAROUND(BOOST_GCC, < 40900) && !BOOST_WORKAROUND(BOOST_CLANG_VERSION, < 30800)
+    {
+        boost::array<int, 3> b = boost::to_array({ 1, 2, 3 });
+
+        BOOST_TEST_EQ( b[0], 1 );
+        BOOST_TEST_EQ( b[1], 2 );
+        BOOST_TEST_EQ( b[2], 3 );
+    }
+#endif
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, < 1920)
+    {
+        std::unique_ptr<int> a[] = { {}, {}, {} };
+
+        boost::array<std::unique_ptr<int>, 3> b = boost::to_array( std::move( a ) );
+
+        (void)b;
+    }
+#endif
+
+#endif
+
+    return boost::report_errors();
+}

test/to_array_test_cx.cpp

@@ -0,0 +1,32 @@
+// Copyright 2025 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/array.hpp>
+#include <boost/config.hpp>
+#include <boost/config/pragma_message.hpp>
+#include <boost/config/workaround.hpp>
+#include <cstddef>
+
+#if defined(BOOST_NO_CXX14_CONSTEXPR)
+
+BOOST_PRAGMA_MESSAGE("Test skipped because BOOST_NO_CXX14_CONSTEXPR is defined")
+
+#else
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+
+int main()
+{
+    {
+        constexpr int a[] = { 1, 2, 3, 4 };
+        constexpr boost::array<int, 4> b = boost::to_array( a );
+
+        STATIC_ASSERT( b[0] == 1 );
+        STATIC_ASSERT( b[1] == 2 );
+        STATIC_ASSERT( b[2] == 3 );
+        STATIC_ASSERT( b[3] == 4 );
+    }
+}
+
+#endif