Hi all,

I have some object with multiple inheritance :

class D : public B1, public B2

I made XS interface for B1,B2 and D classes, and I set ISA to match inheritance in the perl packages.

I have a function that have parameters from type B2 and I want to pass a D to this function. 

int func(B2* obj1,B2* obj2){
    return     obj1 == obj2;
}

D* d_ptr = new D();<BR>
B2* b2_ptr = dynamic_cast<B2*>(d_ptr);<BR>
func(d_ptr,b2_ptr); --> return true

[download]

this works fine in full C++ but in the XS mapping the following process is in action: D* object is cast on a void* to be came a perl reference. then this void * is cast into a B2*.

here is my perlobject.map:

# "perlobject.map"  Dean Roehrich, version 19960302<BR>
#<BR>
# TYPEMAPs<BR>
#<BR>
############################################################<BR>
OUTPUT<BR>
 
# The Perl object is blessed into 'CLASS', which should be a<BR>
# char* having the name of the package for the blessing.<BR>
T_X_PTR<BR>
    sv_setref_pv( $arg,${ntype}_Package, (void*)$var );<BR>
<p> 
############################################################<BR>
INPUT<BR>
 
T_X_PTR<BR>
    if(sv_derived_from($arg,${ntype}_Package)) { <BR>
        IV tmp_ = SvIV((SV*)SvRV($arg));<BR>
        $var = ($type)tmp_;<BR>
    }<BR>
    else<BR>    
        croak(\"$var is not of type %s\",${ntype}_Package);<BR>

[download]

if I compare the final B2* and the original D*, the address of the pointed object has changed due to the void* cast that do not work correctly with multiple inheritance.
This is a problem for me because I compare addresses of objects. so that the function return false!!

Do you know how to fix this?
Is there a safe way to map multiple inherited objects in perl ??

thanks in advance

Edit kudra, 2001-08-08 Added code tags

In reply to XS typemap and C++ multiple inheritance by FrenchZ

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