Re^4: how ! operator works

[ikegami]

in reply to Re^3: how ! operator works
in thread how ! operator works

So I looked at the code to answer your question. It looks like it's a hack, not a magical value. The refcount can go down, but it gets reset back to the max for SvIMMORTAL variables (the true, the false, the undef and a special internal thing called "placeholder").

[arkturuz]

So I looked at the code to answer your question.
Thanks! I searched the code myself today with no luck. I postoponed it for the weekend but now you have resolved this, I'll just have to stick to something else to do :)

[ikegami]

My answer is more or less an educated guess. If you want to look around to confirm or for fun, PL_sv_no is the SV returned when a builtin wants to return something false. An interesting puzzle would be to see if you can manage to lower the refcount and display it at the lower refcount using Devel::Peek's Dump.