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Date: Tue, 03 Dec 2013 13:39:45 +0100
From: Juan Manuel Guerrero <juan DOT guerrero AT gmx DOT de>
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To: djgpp AT delorie DOT com
Subject: Re: Question about different behavior of fclose/fread on plain dos
 and windows.
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Reply-To: djgpp AT delorie DOT com

Am 03.12.2013 08:02, schrieb Eli Zaretskii:
>> Date: Tue, 03 Dec 2013 03:40:10 +0100
>> From: Juan Manuel Guerrero <juan DOT guerrero AT gmx DOT de>
>>
>> The code shall open the same file for writing and reading.  I have compiled
>> the code on linux and on Win98SE, Win2K and WinXP.  On windows I have used
>> DJGPP 2.03 and DJGPP 2.04.  In all these cases the code works as I expected.
>> This means that reading after having closed the file shall result in a filled
>> buf_r.  The program gives the following output:
>>
>> fwrite(fw) OK (7): pipapo
>> fread(fr) OK (0):
>> fread(fr) OK (7): pipapo
>>
>>
>> But if I compile the same code on plain DOS (MSDOS 6.22 or MSDOS 7.1) the program
>> fails producing the following output:
>> fwrite(fw) OK (7): pipapo
>> fread(fr) OK (0):
>> fread(fr) FO (0):
>>
>>
>> (If you run the program twice on plain dos remove the produced file.txt before
>> starting the program or the program will seem to work.)
> Does it work reliably if you open the file for reading only after its
> write handle is closed?  How about if you call clearerr on the stream,
> before the second read?

It has no influence if I call clearerr.  The flags that are cleared are not set
before the call.  It works reliably in all variants if I open the file for reading
after having closed the write handle.


Regards,
Juan M. Guerrero