A.9 The Generic Package Storage_IO
The generic package Storage_IO provides for reading from and writing to an in-memory buffer. This generic package supports the construction of user-defined input-output packages.
The generic library package Storage_IO has the following declaration:
with Ada.IO_Exceptions; with System.Storage_Elements; generic type Element_Type is private; package Ada.Storage_IO is pragma Preelaborate(Storage_IO);
Buffer_Size : constant System.Storage_Elements.Storage_Count := implementation-defined; subtype Buffer_Type is System.Storage_Elements.Storage_Array(1..Buffer_Size);
-- Input and output operations
procedure Read (Buffer : in Buffer_Type; Item : out Element_Type);
procedure Write(Buffer : out Buffer_Type; Item : in Element_Type);
Data_Error : exception renames IO_Exceptions.Data_Error; end Ada.Storage_IO;
In each instance, the constant Buffer_Size has a value that is the size (in storage elements) of the buffer required to represent the content of an object of subtype Element_Type, including any implicit levels of indirection used by the implementation. The Read and Write procedures of Storage_IO correspond to the Read and Write procedures of Direct_IO (see A.8.4), but with the content of the Item parameter being read from or written into the specified Buffer, rather than an external file.
21 A buffer used for Storage_IO holds only one element at a time; an external file used for Direct_IO holds a sequence of elements.
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Copyright © 2000 The MITRE Corporation, Inc. Ada Reference Manual