Nick Withers napsal/wrote, On 06/20/06 04:53:
To Nick: OS doesn't zero on free.
FreeBSD does*, if the "J" flag is set in _malloc_options /
You speak what the libc does, not about OS itself. I can wrote program
using brk/sbrk (another libc functions) to manage it's memory. It set
the "end margin" of program's data segment. I think it doesn't zero the
end of data segment before shrinking. But I need no libc to wrote a
program at all ...
Well, if we want to speak about OS memory management we need to clarify
what the memory we speak of and what exactly we thing saying "free of a
memory".
* Alright, it doesn't zero, as such, but will (again, unless
I've misunderstood the malloc(3) man page) initialise each byte
to 0xd0
2006/6/20, Nick Withers <[EMAIL PROTECTED]>:
> There's "Z" malloc option that's used to initialise page with zeros
> instead of 0xd0
Difference betwen Z and J isn't the fill value only. Z apply for
allocations of new memory (when imalloc() called); J apply on changes in
allocated block size (e.g. realloc) and free. So 'Z' doesn't "zero on
free" but "zero on alloc". Well, things aren't simple as Z implies J ...
BTW, Z nor J doesn't imply 'R' despite of text of manual page.
Dan
--
Dan Lukes SISAL MFF UK
AKA: [EMAIL PROTECTED], [EMAIL PROTECTED],[EMAIL PROTECTED]
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