bitwise & has a lower precedence that == , so perl thinks your code is this

return unless $ds[2] & ( $mask == $mask)

try adding more brackets to get it do do what you want.

return unless  ($ds[2] & $mask) == $mask;

There is a table of operators in precedence order in perlop

In reply to Re: bitwise AND against a variable containing Fnctl constants not returning desired results by RichardK
in thread bitwise AND against a variable containing Fnctl constants not returning desired results by theillien1

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