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From: Rob Norris <firstname.lastname@baesystems.com>
Newsgroups: comp.lang.ada
Subject: Re: How to exit an Ada program with (unix shell) error code?
Date: Tue, 05 May 2009 11:49:54 +0100
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Date: 2009-05-05T11:49:54+01:00
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On Mon, 04 May 2009 16:09:01 GMT, anon@anon.org (anon) wrote:

>
>--
>--  Besides the Ada.Command_Line you can just use functions for 
>--  the instead of procedures for your nain program. This design is 
>--  great for application where Command_Line is not used.
>--
>
>function work return Integer is
>
>  begin
>    return ( 0 ) ; -- no error status code
>  end work ;
>
>
>
>In <49ba30c9-a1e6-4346-8618-d256f87ac301@s31g2000vbp.googlegroups.com>, reinkor <reinkor@gmail.com> writes:
>>I want to use Ada programs within unix/linux makefiles and shell
>>scripts.
>>Then these programs must sometimes exit with an exit code (error
>>status)
>>so execution of the Makefile/scripts halts.
>>
>>How I do this ?
>>
>>reinert

Further to anon's reply, when your main program is a function, you can obviously return various
other values. I think in UNIX world anything other than 0 means an error, but one can encode
different error states of your own choosing eg:

if (not File_Exists (file)) then
	return (3); -- File not found
end if;

if (not In_Correct_Format (file)) then
	return (15); -- Dodgy file
end if;

etc...

Also see: http://www.faqs.org/docs/abs/HTML/exitcodes.html

I have a few programs that do this, that are called from scripts that use the exit code to determine
what to do next.