Re: Consensus: Tuning runtime behaviour with environment variables.

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