Ada 编程/库/Interfaces.C.Pointers

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此语言功能从 Ada 95 开始可用。

接口.C.指针 是自 Ada 95 以来 预定义语言环境 的一个单元。

规范

--                     Standard Ada library specification
--   Copyright (c) 2003-2018 Maxim Reznik <reznikmm@gmail.com>
--   Copyright (c) 2004-2016 AXE Consultants
--   Copyright (c) 2004, 2005, 2006 Ada-Europe
--   Copyright (c) 2000 The MITRE Corporation, Inc.
--   Copyright (c) 1992, 1993, 1994, 1995 Intermetrics, Inc.
--   SPDX-License-Identifier: BSD-3-Clause and LicenseRef-AdaReferenceManual
-- -------------------------------------------------------------------------

generic
   type Index is (<>);
   type Element is private;
   type Element_Array is array (Index range <>) of aliased Element;
   Default_Terminator : Element;
package Interfaces.C.Pointers is
   pragma Preelaborate (Pointers);

   type Pointer is access all Element;

   function Value (Ref        : in Pointer;
                   Terminator : in Element := Default_Terminator)
                  return Element_Array;

   function Value (Ref    : in Pointer;
                   Length : in ptrdiff_t)
                  return Element_Array;

   Pointer_Error : exception;

   --  C-style Pointer arithmetic

   function "+" (Left : in Pointer;   Right : in ptrdiff_t) return Pointer;
   function "+" (Left : in ptrdiff_t; Right : in Pointer)   return Pointer;
   function "-" (Left : in Pointer;   Right : in ptrdiff_t) return Pointer;
   function "-" (Left : in Pointer;   Right : in Pointer) return ptrdiff_t;

   procedure Increment (Ref : in out Pointer);
   procedure Decrement (Ref : in out Pointer);

   pragma Convention (Intrinsic, "+");
   pragma Convention (Intrinsic, "-");
   pragma Convention (Intrinsic, Increment);
   pragma Convention (Intrinsic, Decrement);

   function Virtual_Length (Ref        : in Pointer;
                            Terminator : in Element := Default_Terminator)
                           return ptrdiff_t;

   procedure Copy_Terminated_Array
     (Source     : in Pointer;
      Target     : in Pointer;
      Limit      : in ptrdiff_t := ptrdiff_t'Last;
      Terminator : in Element :=  Default_Terminator);

   procedure Copy_Array (Source  : in Pointer;
                         Target  : in Pointer;
                         Length  : in ptrdiff_t);

end Interfaces.C.Pointers;

另见

华夏公益教科书

• Ada 编程/库/接口
• Ada 编程/库/Interfaces.C

外部示例

• 在以下位置搜索 Interfaces.C.Pointers 的 示例：Rosetta Code，GitHub (gists)，任何 Alire 包 或 本华夏公益教科书。
• 在以下位置搜索与 Interfaces.C.Pointers 相关的 帖子：Stack Overflow，comp.lang.ada 或 任何与 Ada 相关的页面。

Ada 参考手册

Ada 95

• B.3.2：通用包 Interfaces.C.Pointers ^[注释]

Ada 2005

• B.3.2：通用包 Interfaces.C.Pointers ^[注释]

Ada 2012

• B.3.2：通用包 Interfaces.C.Pointers ^[注释]

开源实现

FSF GNAT

• 规范：i-cpoint.ads
• 主体：i-cpoint.adb

drake

• 规范：interfaces/i-cpoint.ads
• 主体：interfaces/i-cpoint.adb