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From: Alan Brain <aebrain@dynamite.com.au>
Subject: Re: Ada and robots
Date: 1997/06/27
Message-ID: <33B4768B.75CA@dynamite.com.au>#1/1
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References: <9706262213.AA13647@stealth.ctron.com>
Organization: @Home
Reply-To: aebrain@dynamite.com.au
Newsgroups: comp.lang.ada
Date: 1997-06-27T00:00:00+00:00
List-Id: <comp.lang.ada>


Huy Vo wrote:

> Someone has to care, Jon. Because  if you dynamically  allocate memory
> at 101 places in your 100K lines of code and only one of
> the allocations failed, you really want to know which one failed.
> As an application programmer what would you do? As a compiler writer
> that has to provide a default handler for this type of situation
> what would you do?
> 
> In C, it's as simple as
> 
>   if (!(cp =malloc(BIG_CHUNK)) {
>     fprintf(stderr, "Buy some more ram, i died at line %d\n", __LINE__);
>     exit(1);
>    }
> 
> Show me your code.

In Ada-83,

when STORAGE_ERROR =>
 PUT("Storage Error for Module: " & ModuleName & "  At line: ");
 PUT(LineCount);
 raise;

Naturally this means you must set variables ModuleName (a string) and
LineCount (a positive) in the code. You also need to have

 with TEXT_IO; use TEXT_IO.  

and

 exception

somewheres. But as your C code didn't mention the #includes required for
the use of stderr, fprintf, and the non-portable definition of __LINE__
I think this is fair. Especially since the Ada is completely portable.

Oh yes, the "raise" statement doesn't just give a meaningless error code
(1), it tells the caller that this is a STORAGE_ERROR, and allows them
to use a different technique/algorithm that won't be so
memory-intensive.
   
-- 
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