While undef @array frees up the memory, it only frees it up for perl to use, not for the OS. At least, that's what I remember from long ago in mod_perl discussions. Can someone confirm this?

Update: In Windows: (Numbers from Task Manager)

print("Press Enter to allocate a big chunk of memory.");
<STDIN>;
@a = (0..100000);
print("Memory allocated.\n");
print("Press Enter to free it.");
<STDIN>;
undef @a;
print("Memory freed.\n");
print("Press Enter to exit perl.");
<STDIN>;

__END__
6,328K initially
8,332K after allocating
7,952K after freeing.

[download]
print("Press Enter to allocate a big chunk of memory.");
<STDIN>;
{
   my @a = (0..100000);
   $a[0] = $a[0];
   print("Memory allocated.\n");
   print("Press Enter to free it.");
   <STDIN>;
}
print("Memory freed.\n");
print("Press Enter to exit perl.");
<STDIN>;

__END__
6,328K initially
6,728K after allocating
6,728K after freeing

[download]

In reply to Re: Garbage Collection and undef by ikegami
in thread Garbage Collection and undef by Irinotecan

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