[libc-commits] [llvm] [flang] [libcxx] [clang] [libc] [mlir] [libc++][memory] P1132R8: out_ptr - a scalable output pointer abstraction (PR #73618)
Louis Dionne via libc-commits
libc-commits at lists.llvm.org
Thu Dec 14 08:31:14 PST 2023
================
@@ -0,0 +1,102 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___INOUT_PTR_H
+#define _LIBCPP___INOUT_PTR_H
+
+#include <__config>
+#include <__memory/addressof.h>
+#include <__memory/pointer_traits.h>
+#include <__memory/shared_ptr.h>
+#include <__memory/unique_ptr.h>
+#include <__type_traits/is_same.h>
+#include <__type_traits/is_specialization.h>
+#include <__type_traits/is_void.h>
+#include <tuple>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+# pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 23
+
+template <class _Smart, class _Pointer, class... _Args>
+class _LIBCPP_TEMPLATE_VIS inout_ptr_t {
+ static_assert(!__is_specialization_v<_Smart, shared_ptr>, "std::shared_ptr<> is not supported");
+
+public:
+ _LIBCPP_HIDE_FROM_ABI explicit inout_ptr_t(_Smart& __s, _Args... __args)
+ : __s_(__s), __a_(std::forward<_Args>(__args)...), __p_([&__s] {
+ if constexpr (is_pointer_v<_Smart>) {
+ return __s;
+ } else {
+ return __s.get();
+ }
+ }()) {
+ if constexpr (requires { __s.release(); }) {
+ __s.release();
+ } else {
+ __s = _Smart();
+ }
----------------
ldionne wrote:
Now here you actually want to use `__s_`, not the argument. It's equivalent because they're references but semantically what you're doing is resetting your internal smart pointer, not the argument.
https://github.com/llvm/llvm-project/pull/73618
More information about the libc-commits
mailing list