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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: Package procedure as program entry in GPR project
Date: Sat, 26 Jan 2019 12:05:35 +0000
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Date: 2019-01-26T12:05:35+00:00
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"Randy Brukardt" <randy@rrsoftware.com> writes:

> "Jesper Quorning" <jesper.quorning@gmail.com> wrote in message 
> news:9c44582e-faff-4498-88e1-c8715471e857@googlegroups.com...
[...]
>> package My_Program_Package is
>>   procedure Program_Entry_Procedure;
>> end My_Program_Package;
>>
>> How do i make Program_Entry_Procedure as the program entry procedure
>> in a GPR project?
>
> I realize you are asking for GPR, so by definition you don't care
> about portability, but:
>
> Ada only requires Ada implementations to support library-level
> procedures as the main. See 10.2(29). A particular implementation can
> allow more, but there is no requirement.

This isn't a GPR thing, it's a GNAT thing: GNAT has no extensions here
beyond the requirement.

If you have a minimal bare-board project without any requirement for the
Ada runtime system, it's possible to do what you ask: see Maciej
Sobczak's 'Ada and SPARK on ARM Cortex-M' tutorial[1], in particular the
'First Chapter'[2].

It would be hard (and pointless) to attempt this for a program intended
to run on a typical operating system.

[1] http://www.inspirel.com/articles/Ada_On_Cortex.html
[2] http://www.inspirel.com/articles/Ada_On_Cortex_First_Program.html