TYPEMAP
SANE_Auth_Callback              T_PTRREF
SANE_Bool                       T_BOOL
SANE_Handle                     T_SANE_HANDLE
SANE_Int                        T_IV
SANE_Status                     T_IV
SANE_String_Const               T_PV
INPUT
T_SANE_HANDLE
   if (sv_derived_from($arg, \"Image::Sane::Device\")) {
       $var = INT2PTR (SANE_Handle, SvIV ((SV*)SvRV ($arg)));
   } else {
       croak(\"$var is not of type Image::Sane::Device\");
   }
OUTPUT
T_SANE_HANDLE
   sv_setref_pv($arg, \"SANE_Handle\", (void*)$var);