Re: Understanding {$I-} {$I+} ioResult

Le 25 nov. 2012 à 21:51, Prof A Olowofoyeku (The African Chief) a écrit :

> On 25 Nov 2012 at 16:31, Baudouin Le Charlier wrote:
> 
>> 
>> Le 25 nov. 2012 à 15:13, Prof A Olowofoyeku (The African Chief) a écrit
>> :
>> 
>>> On 25 Nov 2012 at 12:13, Baudouin Le Charlier wrote:
>>> 
>>>> It seems that {$I-} is not enough to disable the automatic handling
>>>> of IO errors. 
>>> 
>>> I doesn't disable error checking. It just stops it from automatically
>>> terminating the program immediately it encounters an I/O error.
>> 
>> That's what I finally guessed but not what was explained in the
>> documentation I could find.
> 
> IOResult and {$I-/+} are Borland Pascal/Delphi compatibility issues. It 
> stands to reason that expect that anyone who wants to use non-standard 
> features (i.e., Borland Pascal/Delphi features) would have sufficient 
> knowledge of Borland Pascal/Delphi to appreciate how those features are 
> meant to be used. 

What are the standard features ? To me the standard features are just the original definition of files in Pascal given in Jensen and Wirth's book but they are incomplete and an actual implementation needs additional conventions.


> 
> This is a historical factor, and there was no need to duplicate 
> features that Borland already documented well, and which were well 
> known to Borland Pascal/Delphi programmers.

I am not sure they are so well known since you did not explain to me why (i.e. by which miracle) a program that stops abruptly (when compiled with $I-), stops normally if you add a call to ioResult *after* the io statement that makes the original program fail. I doubt very much that this could be explained in the original Borland documentation and also that this behavior should be well known of Borland Pascal programmers.

Best regards,

Baudouin

> 
> Perhaps someone should now duplicate that information - but I doubt 
> whether it would be a sensible use of anyone's time. Just find the 
> Borland Pascal and Delphi help files (freely available on the net), and 
> you would find full documentation of these features.
> Best regards, The Chief
> --------
> Prof. Abimbola A. Olowofoyeku (The African Chief) 
> web:  http://www.greatchief.plus.com/
> 
> 
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