Exactly. So, the system locks the SV without the programmer being aware of it. Not a problem if one thread does so, but then, no lock would have been necessary. But if two threads try to write at once, an exception will be raced. And this all happens behind the programmers back - the programmer thinks she's only doing a read access to a variable (and on a Perl level, she does), but the value is locked anyway.

For a programmer to defend against this, she needs to know all the details of the perl internals. Which, IMO, is not a good thing. (I'm not saying it's a bad thing if more people know the internals of perl - I'm saying it's a bad thing that in order to write a good program, one has to know the internals of perl).

In reply to Re^3: A faster?, safer, user transparent, shared variable "locking" mechanism. by Anonymous Monk
in thread A faster?, safer, user transparent, shared variable "locking" mechanism. by BrowserUk

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