I don't know much about XS, but I wonder if this code is able to distinguish between when it's passed undef and when it's passed 0. That is, can it see the difference between foo( undef, undef ) and foo( 0, 0 )? It seems to me the "uninitialized value" warning is undef getting turned into 0.

In reply to Re^4: Passing undef to XSUB by kyle
in thread Passing undef to XSUB by pileofrogs

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