Add array_c_array_test.cpp

test/array_c_array_test.cpp

@@ -0,0 +1,70 @@
+// 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 <cstddef>
+
+// c_array and get_c_array are nonstandard extensions
+// probably need to be deprecated and removed
+
+template<class T, std::size_t N> void test()
+{
+    boost::array<T, N> a = {};
+
+    T* p1 = a.c_array();
+    T* p2 = a.data();
+
+    BOOST_TEST_EQ( p1, p2 );
+}
+
+template<class T, std::size_t N> void test2()
+{
+    {
+        boost::array<T, N> a = {{}};
+
+        T (&e1)[ N ] = boost::get_c_array( a );
+        T (&e2)[ N ] = a.elems;
+
+        BOOST_TEST_EQ( static_cast<T*>( e1 ), static_cast<T*>( e2 ) );
+    }
+    {
+        boost::array<T, N> const a = {{}};
+
+        T const (&e1)[ N ] = boost::get_c_array( a );
+        T const (&e2)[ N ] = a.elems;
+
+        BOOST_TEST_EQ( static_cast<T const*>( e1 ), static_cast<T const*>( e2 ) );
+    }
+}
+
+int main()
+{
+    test<int, 0>();
+    test<int, 1>();
+    test<int, 7>();
+
+    test<int const, 0>();
+
+#if BOOST_WORKAROUND(BOOST_MSVC, < 1910) || BOOST_WORKAROUND(BOOST_GCC, < 50000)
+
+    // = {} doesn't work for const T
+
+#else
+
+    test<int const, 1>();
+    test<int const, 7>();
+
+#endif
+
+    test2<int, 1>();
+    test2<int, 7>();
+
+    test2<int const, 1>();
+    test2<int const, 7>();
+
+    return boost::report_errors();
+}