Ada Reference Manual (Ada 2022) — Legal Information

# A.9 The Generic Package Storage_IO

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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.

#### Static Semantics

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The generic library package Storage_IO has the following declaration:
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with Ada.IO_Exceptions;
with System.Storage_Elements;
generic
type Element_Type is private;
package Ada.Storage_IO
with Preelaborate, Global => in out synchronized is
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Buffer_Size : constant System.Storage_Elements.Storage_Count :=
implementation-defined;
subtype Buffer_Type is
System.Storage_Elements.Storage_Array(1..Buffer_Size);
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-- Input and output operations
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procedure Read (Buffer : in Buffer_Type; Item : out Element_Type);
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procedure Write(Buffer : out Buffer_Type; Item : in Element_Type);
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-- Exceptions
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Data_Error : exception renames IO_Exceptions.Data_Error;
end Ada.Storage_IO;
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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.
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NOTE 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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