整理

include/boost/scope/detail/is_nonnull_default_constructible.hpp

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+/*
+ * 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)
+ *
+ * Copyright (c) 2023 Andrey Semashev
+ */
+/*!
+ * \file scope/detail/is_nonnull_default_constructible.hpp
+ *
+ * This header contains definition of \c is_nonnull_default_constructible
+ * and \c is_nothrow_nonnull_default_constructible type traits. The type
+ * traits are useful for preventing default-construction of pointers to
+ * functions where a default-constructed function object is expected.
+ * Without it, default- or value-constructing a pointer to function would
+ * produce a function object that is not callable.
+ */
+
+#ifndef BOOST_SCOPE_DETAIL_IS_NONNULL_DEFAULT_CONSTRUCTIBLE_HPP_INCLUDED_
+#define BOOST_SCOPE_DETAIL_IS_NONNULL_DEFAULT_CONSTRUCTIBLE_HPP_INCLUDED_
+
+#include <type_traits>
+#include <boost/scope/detail/config.hpp>
+#include <boost/scope/detail/header.hpp>
+
+#ifdef BOOST_HAS_PRAGMA_ONCE
+#pragma once
+#endif
+
+namespace boost {
+namespace scope {
+namespace detail {
+
+//! The type trait checks if \c T is not a pointer and is default-constructible
+template< typename T >
+struct is_nonnull_default_constructible :
+    public std::is_default_constructible< T >
+{
+};
+
+template< typename T >
+struct is_nonnull_default_constructible< T* > :
+    public std::false_type
+{
+};
+
+//! The type trait checks if \c T is not a pointer and is nothrow-default-constructible
+template< typename T >
+struct is_nothrow_nonnull_default_constructible :
+    public std::is_nothrow_default_constructible< T >
+{
+};
+
+template< typename T >
+struct is_nothrow_nonnull_default_constructible< T* > :
+    public std::false_type
+{
+};
+
+} // namespace detail
+} // namespace scope
+} // namespace boost
+
+#include <boost/scope/detail/footer.hpp>
+
+#endif // BOOST_SCOPE_DETAIL_IS_NONNULL_DEFAULT_CONSTRUCTIBLE_HPP_INCLUDED_