The regex engine currently always makes a CoW copy (ie doesn't copy the string itself) of the matched string.

There's no CoW substrings - perl's PVs are stored with a trailing NUL so they're useful as a C-style string, and perl itself and XS code depends on that, so I don't think it can be implemented in any case.

In reply to Re^5: RE on lines read from in-memory scalar is very slow by tonyc
in thread RE on lines read from in-memory scalar is very slow by Danny

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