Since this is a 'test & set',

It certainly isn't implemented using an atomic instruction, so yes. If $PageQueue is a shared variable, and the statement is part of a thread function body that may be instantiated more than once, you need to lock it before setting it.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
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In reply to Re: is ||= threadsafe? by BrowserUk
in thread is ||= threadsafe? by perl-diddler

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