I think gv_fetchmethod() is sort of what I was looking for. In the situation I'm working with, perl passes to SV's to an XSUB. I verify (in one particular code branch) that the first is a reference to a blessed object, and that the second is a string. I would like to verify that the string is a valid method on the object before I call call_method(). The tricky bit is, I don't know the class name of the blessed object, I just have an instance reference. Is there some way to get the class name of the object?