A.8.1 The Generic Package Sequential_IO
Static Semantics
1
The generic library
package Sequential_IO has the following declaration:
2
with Ada.IO_Exceptions;
generic
type Element_Type(<>)
is private;
package Ada.Sequential_IO
is
3
type File_Type
is limited private;
4
type File_Mode
is (In_File, Out_File, Append_File);
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-- File management
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procedure Create(File :
in out File_Type;
Mode :
in File_Mode := Out_File;
Name :
in String := "";
Form :
in String := "");
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procedure Open (File :
in out File_Type;
Mode :
in File_Mode;
Name :
in String;
Form :
in String := "");
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procedure Close (File :
in out File_Type);
procedure Delete(File :
in out File_Type);
procedure Reset (File :
in out File_Type; Mode :
in File_Mode);
procedure Reset (File :
in out File_Type);
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function Mode (File :
in File_Type)
return File_Mode;
function Name (File :
in File_Type)
return String;
function Form (File :
in File_Type)
return String;
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function Is_Open(File :
in File_Type)
return Boolean;
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-- Input and output operations
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procedure Read (File :
in File_Type; Item :
out Element_Type);
procedure Write (File :
in File_Type; Item :
in Element_Type);
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function End_Of_File(File :
in File_Type)
return Boolean;
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-- Exceptions
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Status_Error :
exception renames IO_Exceptions.Status_Error;
Mode_Error :
exception renames IO_Exceptions.Mode_Error;
Name_Error :
exception renames IO_Exceptions.Name_Error;
Use_Error :
exception renames IO_Exceptions.Use_Error;
Device_Error :
exception renames IO_Exceptions.Device_Error;
End_Error :
exception renames IO_Exceptions.End_Error;
Data_Error :
exception renames IO_Exceptions.Data_Error;
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private
... -- not specified by the language
end Ada.Sequential_IO;
17/2
{
AI95-00360-01}
The type File_Type needs finalization (see 7.6)
in every instantiation of Sequential_IO.Incompatibilities With Ada 83
17.a
{
incompatibilities with Ada 83}
The
new enumeration element Append_File may introduce upward incompatibilities.
It is possible that a program based on the assumption that File_Mode'Last
= Out_File will be illegal (e.g., case statement choice coverage) or
execute with a different effect in Ada 95.
17.a.1/2
This paragraph
was deleted.Implementation Note:
{
8652/0097}
{
AI95-00115-01}
{
AI95-00344-01}
File_Type
cannot be implemented as a (directly) controlled type, as Ada.Sequential_IO
can be instantiated at any nesting depth. File_Type could have a component
of a controlled type, as long as that type is declared in some other
(non-generic) package.
Incompatibilities With Ada 95
17.b/2
{
AI95-00360-01}
{incompatibilities with Ada 95} Amendment
Correction: File_Type in an instance of Sequential_IO is defined
to need finalization. If the restriction No_Nested_Finalization (see
D.7) applies to the partition, and File_Type
does not have a controlled part, it will not be allowed in local objects
in Ada 2005 whereas it would be allowed in original Ada 95. Such code
is not portable, as another Ada compiler may have a controlled part in
File_Type, and thus would be illegal.
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