For those interested in the gory details, I found a way to display the HTML with images from illguts on metacpan

https://st.aticpan.org/source/RURBAN/illguts-0.49/index.html

0x20000000 SVphv_SHAREKEYS

When this flag is set, then the hash will share the HEK structures with a special hash pointed to by the strtab variable. This reduce the storage occupied by hash keys, especially when we have lots of hashes with the same keys. The SHAREKEYS flag is on by default for newly created HVs.

Since 5.10:strtab.image

What is special with the strtab hash is that the val field of the HE structs is used as a reference counter for the HEK. The counter is incremented when new hashes link up this HEK and decremented when the key is removed from the hashes. When the reference count reach 0, the HEK (and corresponding HE) is removed from strtab and the storage is freed.

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery

In reply to Re: do separate hashes share common keys? by LanX
in thread do separate hashes share common keys? by LanX

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