What warnings do you get exactly? Surely not from the if (!$r): 
$ perl -le 'use warnings; if (!undef) { print "foo" }'
foo

[download]

No warning from !undef.

So first you should find out what's the cause for the warning.

Then you can read perllexwarn on how to disable warnings selectively.

In reply to Re: selective warnings by moritz
in thread selective warnings by baxy77bax

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