using an expr~ object like:
[expr~ if($v1==0, 1, sin($v1)/$v1)]
it produces a message in the Pd console:
expr~ divide by zero detected
although this may be correct from an internals point of view, what I did is explicitly catching the divide-by-zero, and replace it with a constant value.
so, why the message?
in addition, the message gets repeated many times (perhaps this is the most annoying thing, but not the centre of the problem)