Re^3: memory "release" with $#=-1

in reply to Re^2: memory "release" with $#=-1
in thread memory "release" with $#=-1

my $a = [];
$a->[$_] = $_ for 0..999;
$#$a = 1; # frees up  approx 16000 bytes
undef @$a; # frees a further 4000 bytes
undef $a;  # frees a further 52 bytes
[download]

Note that this frees memory to the perl interpter, not to the OS. ie perl can reuse that memory when creating further data, but other processes can't

update: to clarify: just doing the undef $a on its own would free up all 20052 bytes too.

Dave.

Comment on Re^3: memory "release" with $#=-1 Download Code

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Re^4: memory "release" with $#=-1 by ISAI student (Scribe) on Jun 28, 2005 at 14:01 UTC
OK. That's great, I'll use it to free up memory. Thanks for all your help. -ISAI student	[reply]
Re^4: memory "release" with $#=-1 by waswas-fng (Curate) on Jun 28, 2005 at 19:22 UTC
One note though, if you create the array peicemail over time, then you may have smaller portions of memory allocated for the array that are not contiguous. In that case freeing the array and making a new array may not use the freed memory if the new array has larger malloc needs then the freed memory has contiguous memory segments. -Waswas	[reply]
Re^5: memory "release" with $#=-1 by BUU (Prior) on Jun 28, 2005 at 19:31 UTC
I'm pretty sure perl arrays always take up a contiguous region of memory, at least for the actual "array" part. Then again, it's just an array of pointers to SV's anyways, so I'm not sure it matters.	[reply]

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