If it did nothing, it would be harmless. Quite the opposite, it's a bug to use it there. 
>perl -le"for (1..2) { print 'ab' =~ /a/g ? 'match' : 'no match' }"
match
no match

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In reply to Re^2: Extract chunked/gzip data from pcap file (OT: Regex Usage) by ikegami
in thread Extract chunked/gzip data from pcap file by oakb

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