Xref:	news2.mv.net comp.os.msdos.djgpp:3051
From:	alexlehm AT rbg DOT informatik DOT th-darmstadt DOT de (Alexander Lehmann)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Odd printf behaviour
Date:	23 Apr 1996 22:22:27 GMT
Organization:	Technische Hochschule Darmstadt
Lines:	35
Message-ID:	<4ljl73$1ep4@rs18.hrz.th-darmstadt.de>
References:	<4ljetk$bvh AT sulawesi DOT lerc DOT nasa DOT gov>
NNTP-Posting-Host:	hp62.rbg.informatik.th-darmstadt.de
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Gregory Fedor (gfedor AT lerc DOT nasa DOT gov) wrote:
: I wrote some simple code that utilizes the gotoxy() and printf() 
: statements to place text on the screen, ala:

: 	while(!done)
: 	{
: 		gotoxy(column, line);
: 		printf(" %... ", ...);

: 		// update column
: 		// update line
: 	}

: When I run this type of code nothing appears on the screen.  I can see 
: the cursor jumping around, but nothing else.  However, if I include a 
: '\n' in the printf statement, things display fine, *or* as soon as I 
: printf with a '\n' outside the loop, then **all** the text gets 
: displayed.  It's almost as if it's being buffered, and isn't displayed 
: until a '\n' comes along.

This is because the stdout stream is line buffered by default. So the output
is flushed when the buffer is full (1024 chars or something) or if a \n
is printed. To flush the buffer explicitly, you can use the fflush function.
Another possibility is to set stdout to non-buffered mode, but this way the
output becomes slower (since it is done char-by-char), so the first solution
is usually favorable.


bye, Alexander

--
Alexander Lehmann,                                  |  "On the Internet,
alex AT hal DOT rhein-main DOT de  (plain, MIME, NeXT)         |   nobody knows
alexlehm AT rbg DOT informatik DOT th-darmstadt DOT de (plain)     |   you're a dog."
<URL:http://www.student.informatik.th-darmstadt.de/~alexlehm/>

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