If at the perl level your Bar and Baz also inherit from Foo, the call will get accepted in fact. Now if at the C level calling getName will also work on e.g. bar objects even though they are currently in a foo typed variable, then all is fine (depends on how the C level inheritance is done, usually this would work).

But even if it doesn't, you could always build your own polymorphic GetName by simply saying the argument is an SV * and determining the exact type by yourself with something like (untested): 

...
GetName(SV *thingy)
  PREINIT:
    IV tmp;
  CODE:
     if (sv_derived_from(thingy, "Foo")) {
         fooRef foo;
         tmp = SvIV((SV*) SvRV(thingy));
         foo = INT2PTR(fooRef, tmp);
         getName(foo);
     } else if  (sv_derived_from(thingy, "Bar")) {
         barRef bar;
         tmp = SvIV((SV*) SvRV(thingy));
         bar = INT2PTR(barRef, tmp);
         getName(bar);
     } else if (sv_derived_from(thingy, "Baz")) {
         bazRef baz;
         tmp = SvIV((SV*) SvRV(thingy));
         baz = INT2PTR(bazRef, tmp);
         getName(baz);
     } else croak("Some unhandled argument type message");
     ...

[download]

Doing it like that is not necessarily a good idea though. If Foo, Bar and Baz form the basis of separate object hierarchies at the perl level, it probably makes more sense to have a GetName for each object type in your XS code. No need to pollute the accessor name with the type though, just have them all in a different MODULE/PACKAGE section.

In reply to Re: XSUBs with variable input types by thospel
in thread XSUBs with variable input types by crenz

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