Xref: news2.mv.net comp.os.msdos.djgpp:7246
From: Thomas Demmer <demmer AT LSTM DOT Ruhr-UNI-Bochum DOT De>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: interrupting with ctrl-C
Date: Mon, 12 Aug 1996 18:11:18 +0100
Organization: Lehrstuhl fuer Stroemungsmechanik
Lines: 57
Message-ID: <320F65B6.15FB@LSTM.Ruhr-UNI-Bochum.De>
References: <4ungbb$bqa AT news DOT uni-paderborn DOT de>
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To: Jens Jedamzik <jedamzik AT eevmic DOT uni-paderborn DOT de>
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

Jens Jedamzik wrote:
> 
> jacobsen AT kjemi DOT unit DOT no (Elling Jacobsen) schreibt:
> > Hello,
> > I have a program in which I write data records to a
> > number of files. My problem is that when I interrupt
> > the program using ctrl-C, the files are left empty. I guess
> > the reason is that the data are kept in memory and are
> > not dumped to file at interrupt? Is there any way to
> > ensure that all data records are written to file at
> > interrupt?
> 
> No matter, how many data you write in a file, MS-DOS
> recognizese it's actual size only after closing it via a
> system call.
> 
> The simplest way to help your problem could be, to close the
> files after each write access and re-open it in append mode
> before the next write access. (That's the way I used for my
> data logger.)
> 
> Another possible solution is/might be (?) to reditrect the
> interrupt to an exit routine that closes all your files.

Doesn't do the exit() routine a fcloseall() anyway?

> 
> I hope, that will help you...
> 
> Jens

Maybe it is better to fflush() after every write? I think 
closing and reopening has a bit too much overhead for that.

I am not sure if fflush() also flushes the DOS buffers or 
only the djgpp internal buffers, but from a short glance
I saw it just calls DOS21/4000. 

If you write more than 16kB (i.e the default xfer buffer size
for djgpp) you _should_ see something on disk. If not, the problem
is somewhere else. 

-- 
Ciao
Tom

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* Thomas Demmer                                             *
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