Xref: news2.mv.net comp.os.msdos.djgpp:7175
From: "John M. Aldrich" <fighteer AT cs DOT com>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: interrupting with ctrl-C
Date: Mon, 12 Aug 1996 20:27:12 -0700
Organization: Three pounds of chaos and a pinch of salt
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Message-ID: <320FF610.1E13@cs.com>
References: <4un5jr$9li AT due DOT unit DOT no>
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To: Elling Jacobsen <jacobsen AT kjemi DOT unit DOT no>
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

Elling Jacobsen wrote:
> 
> 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?

DJGPP (like most compilers) uses buffered i/o to reduce disk
interactions.  To ensure that all data gets written to disk
even though a crash may occur, use the fflush() function.  For
example:

    FILE *fp = fopen( "foo.dat", "w" );
    fprintf( fp, "My name is %s.\n", name );
    fflush( fp );

Note also that data is also written when the internal buffers
are full, but you cannot count on this occurring, especially
with programs that write small chunks of data.

-- 
John M. Aldrich, aka Fighteer I <fighteer AT cs DOT com>

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