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From: sjw <simon.j.wright@mac.com>
Newsgroups: comp.lang.ada
Subject: Re: Deallocation of Unbounded_String
Date: Sat, 25 Jul 2009 10:09:30 -0700 (PDT)
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On Jul 25, 5:37=A0pm, vlc <just.another.spam.acco...@googlemail.com>
wrote:

> when using Unbounded_String, is it necessary to deallocate instances
> of Unbounded_String after use or is there a kind of garbage collector
> implemented?

Unbounded_Strings are controlled, and look after their own memory when
they go out of scope or are overwritten.

If you had a variable currently holding a really huge unbounded string
which you needed to keep in scope you could free its memory by saying

   My_Unbounded_String :=3D Ada.Strings.Unbounded.Null_Unbounded_String;

> There is a "Free" function in Ada.Strings.Unbounded, but it takes an
> access to String as argument, not an access to Unbounded_String.

Hadn't noticed that; no idea why it's there (might be some use in
Ada.Strings.Fixed?)

> If I'm supposed to use this "Free" function to deallocate the memory
> of my unused Unbounded_String, what is the correct usage of this
> function (typecast of "access Unbounded_String" to "access String")?

Very Bad Things would happen if you did this. The memory layout of the
two types of object is going to be entirely different. An
Unbounded_String is likely to be chained through a list of objects to
be finalized when the scope is left - you interfere with that sort of
construct at your peril.