Date: Sun, 05 Jul 2009 14:20:57 +0200 (CEST) From: Alexander Best <alexbestms@math.uni-muenster.de> To: Jilles Tjoelker <jilles@stack.nl> Cc: freebsd-hackers@FreeBSD.org Subject: Re: carriage return with stdout and stderr Message-ID: <permail-200907051220571e86ffa8000022e0-a_best01@message-id.uni-muenster.de> In-Reply-To: <20090705120514.GA45921@stack.nl>
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thanks. i remembered fprintf being buffered, but i always thought \r would also empty the buffer. now that explains everything. ;-) alex Jilles Tjoelker schrieb am 2009-07-05: > On Sun, Jul 05, 2009 at 01:42:01PM +0200, Alexander Best wrote: > > i'm running something similar to this pseudo-code in an app of > > mine: > > for (i=0 ....) > > fprintf(stdout,"TEXT %d\r", int); > > what's really strange is that if i print to stdout the output isn't > > very > > clean. the cursor jumps randomly within the output (being 1 line). > > if i print > > to stderr however the output looks really nice. the cursor says > > right at the > > front of the output all the time. just like in burncd e.g. > > what's causing this? because i'd rather print to stdout. > If you are writing to a terminal, stdout is line-buffered. This means > that output is flushed when the buffer is full or a '\n' is written. > A > '\r' is not good enough. You can force a write using fflush(stdout). > stderr is always unbuffered, so everything is written immediately.
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