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Diffstat (limited to 'src/corelib/global/q23functional.h')
-rw-r--r-- | src/corelib/global/q23functional.h | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/src/corelib/global/q23functional.h b/src/corelib/global/q23functional.h new file mode 100644 index 0000000000..ae8f78a3d0 --- /dev/null +++ b/src/corelib/global/q23functional.h @@ -0,0 +1,49 @@ +// Copyright (C) 2022 The Qt Company Ltd. +// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only +#ifndef Q23FUNCTIONAL_H +#define Q23FUNCTIONAL_H + +#include <QtCore/qglobal.h> +#include <QtCore/q20functional.h> + +// +// W A R N I N G +// ------------- +// +// This file is not part of the Qt API. Types and functions defined in this +// file can reliably be replaced by their std counterparts, once available. +// You may use these definitions in your own code, but be aware that we +// will remove them once Qt depends on the C++ version that supports +// them in namespace std. There will be NO deprecation warning, the +// definitions will JUST go away. +// +// If you can't agree to these terms, don't use these definitions! +// +// We mean it. +// + +QT_BEGIN_NAMESPACE + +namespace q23 { +// like std::invoke_r +#ifdef __cpp_lib_invoke_r +using std::invoke_r; +#else +template <typename R, typename F, typename...Args> +constexpr +std::enable_if_t<std::is_invocable_r_v<R, F, Args...>, R> +invoke_r(F&& f, Args&&... args) + noexcept(std::is_nothrow_invocable_r_v<R, F, Args...>) +{ + // ### use q20::invoke for a constexpr std::invoke + if constexpr (std::is_void_v<R>) + std::invoke(std::forward<F>(f), std::forward<Args>(args)...); + else + return std::invoke(std::forward<F>(f), std::forward<Args>(args)...); +} +#endif // __cpp_lib_invoke_r +} // namespace q23 + +QT_END_NAMESPACE + +#endif /* Q23FUNCTIONAL_H */ |