Frequency of 3.8 Malloc Options Check

[Dave Feustel]

I now have 3.8 installed. Very Nice, especially Firefox.
CDROM Artwork is also nicely done.
My question is re Malloc. When and how often does malloc 
check the flags in MALLOC_OPTIONS. Once at system init, 
on every malloc call, or other? Can I set the options,
run a program, and see if the new options affect the way
the program runs?

Thanks,
Dave Feustel