Re^2: readonly access to C-level strings

What I want to avoid is exactly this copying. The strings are located in a mem segment that is mmapped read-only. So, there is no way for them to be changed and hence no need to be copied.

Comment on Re^2: readonly access to C-level strings

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Re^3: readonly access to C-level strings by ikegami (Patriarch) on Jul 02, 2009 at 16:20 UTC
hence no need to be copied. No, there is a need: For Perl to see them. The buffers of Perl strings are subject to modification and freeing at any time. It might be possible to tell Perl the PV associated with a scalar can't be changed, but there's no way to tell Perl to use a existing memory block for the string buffer of a string, and there's no way to tell Perl the string buffer of a string can't be freed.	[reply]

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Re^3: readonly access to C-level strings
by ikegami (Patriarch) on Jul 02, 2009 at 16:20 UTC

hence no need to be copied.

No, there is a need: For Perl to see them.

The buffers of Perl strings are subject to modification and freeing at any time. It *might* be possible to tell Perl the PV associated with a scalar can't be changed, but

there's no way to tell Perl to use a existing memory block for the string buffer of a string, and
there's no way to tell Perl the string buffer of a string can't be freed.

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