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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: Why can't objects be static in Ada?
Date: Tue, 16 Apr 2019 17:19:52 +0100
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Xref: reader01.eternal-september.org comp.lang.ada:56137
Date: 2019-04-16T17:19:52+01:00
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Mark Lorenzen <mark.lorenzen@gmail.com> writes:

> On Tuesday, April 16, 2019 at 3:40:45 AM UTC+2, Randy Brukardt wrote:
>> >
>> > package Static is
>> >  pragma Preelaborate;
>> 
>> I view this as self-inflicted, because there's no little value to
>> pragma Preelaborate. As I previously noted, compilers will almost
>> always generate the best possible elaboration code whether or not
>> that pragma is applied.  And regardless of C.4, not all preelaborated
>> code can be done before load time, so it isn't providing a benefit in
>> forcing that sort of code, either.
>> 
>> It's one of the ideas where Ada tried to accomplish something, but
>> didn't quite succeed. Pure is like that as well, but at least it
>> provides some benefits for Annex E code. Preelaborate doesn't even do
>> that.
>
> How can it be ensured that a library written in Ada does not require
> any elaboration. Pragma Pure? I think that such libraries are "nice"
> but pragma Pure is too restrictive for that purpose. In such cases it
> would be good, if e.g. the OP's problem could be solved at compile
> time without any elaboration.

The GNAT pragma No_Elaboration_Code_All will do the trick (or fail if it
can't be done).