Message 227098 - Python tracker

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Author	vstinner
Recipients	Sworddragon, vstinner
Date	2014-09-19.14:10:59
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1411135859.34.0.502791535342.issue22443@psf.upfronthosting.co.za>
In-reply-to

Content
> On reading the output of an application (for example "apt-get download firefox") that dynamically changes a line (possibly with the terminal control character \r) I have noticed that read(1) does not read the output until it has finished with a newline. The buffering of stdout and/or stderr of your application probably changes if the application runs in a terminal (TTY) or if the output is redirected to a pipe (not a TTY). Set the setvbuf() function. You can try my hack to disable buffering using LD_PRELOAD: https://bitbucket.org/haypo/misc/src/4d133ea3e46550808305b093557ee51d2de2ac9f/misc/nobuffer.c?at=default

> On reading the output of an application (for example "apt-get download firefox") that dynamically changes a line (possibly with the terminal control character \r) I have noticed that read(1) does not read the output until it has finished with a newline.

The buffering of stdout and/or stderr of your application probably changes if the application runs in a terminal (TTY) or if the output is redirected to a pipe (not a TTY). Set the setvbuf() function.

You can try my hack to disable buffering using LD_PRELOAD:
https://bitbucket.org/haypo/misc/src/4d133ea3e46550808305b093557ee51d2de2ac9f/misc/nobuffer.c?at=default

History
Date	User	Action	Args
2014-09-19 14:10:59	vstinner	set	recipients: + vstinner, Sworddragon
2014-09-19 14:10:59	vstinner	set	messageid: <1411135859.34.0.502791535342.issue22443@psf.upfronthosting.co.za>
2014-09-19 14:10:59	vstinner	link	issue22443 messages
2014-09-19 14:10:59	vstinner	create