MALLOC_OPTIONS behaviour

[rihad]

Under 5.2-BETA, if I run a program with "env MALLOC_OPTIONS=j" then all 
the malloc()'ed memory will be zeroed even though I did not ask for it 
(by specifying "Z"). Also, "J" (memset to 0xd0) even appears to run a 
somewhat *faster* than "j". Why doesn't "jz" return uninitialized memory 
and isn't the fastest of {jz,J,Z} (where J is the fastest)? I'm new to 
FreeBSD so I don't know if previously this worked as documented in 
malloc(3).

TIA