RFC: Check IFUNC_XXX to enable/disable ifunc feature

[Carlos O'Donell]

On 06/26/2016 10:50 AM, H.J. Lu wrote:
> Hi,
> 
> I'd like to check IFUNC_XXX environmental variable to enable/disable
> the ifunc feature, XXX.  That is
> 
> 1.  IFUNC_XXX=1 to enable XXX.
> 2.  IFUNC_XXX=0 to disable XXX.
> 
> Any comments?

How would it work? Does it just mean that the IFUNC selector bypasses
the disabled choices?

Also it does not meet Tunables consensus:
"Tunable namespace should be clearly defined"
https://sourceware.org/glibc/wiki/TuningLibraryRuntimeBehavior?highlight=%28Tunables%29

Should perhaps be "GLIBC_<VER>_IFUNC_<ARCH>_<PUBLIC_IFUNC_NAME>"?


-- 
Cheers,
Carlos.