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Gmane
From: Mike Frysinger <vapier <at> gentoo.org>
Subject: Re: Consensus: Tuning runtime behaviour with environment variables.
Newsgroups: gmane.comp.lib.glibc.alpha
Date: Thursday 20th June 2013 20:09:10 UTC (over 4 years ago)
On Wednesday 29 May 2013 00:56:50 Carlos O'Donell wrote:
> I'd like to drive some consensus around the idea of using
> environment variables to tune runtime behaviour in glibc.

i probably missed the boat on this, but the way i generally see things:

 - env vars that affect global runtime-immutable things are fine (e.g.
every 
LD_* var we have today ?), assuming of course we have documentation in
place 
(i believe some of the malloc ones were added w/out any documentation which

meant they rarely got used even though they were super useful).

 - i'm not a big fan of env vars that affect default settings when a C API 
(whether it be _np namespaced or whatever) is better off.  that said, i
don't 
really have an answer that satisfies the proposed constraints other than
using 
env vars (changing behavior of programs where recompiling isn't an option).

if the namespace was clearly defined (e.g. using GLIBC_XXX), and we
documented 
things, and we restrict their use to init time (rather than the code always

doing getenv() as then people may abuse it at runtime), then i could
stomach 
it.
-mike
 
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