UVM: explain do_copy method in detail

[Maulik Suthar]

hello, i want to know how exactly a do_copy method works? what is the need of $cast(rhs_, rhs)?
and also why to call the super.do_copy(rhs)??

function void write_xtn::do_copy (uvm_object rhs);
 
    // handle for overriding the variable
    write_xtn rhs_;
    if(!$cast(rhs_,rhs)) begin
    `uvm_fatal("do_copy","cast of the rhs object failed")
    end
    super.do_copy(rhs);
 
    data= rhs_.data;
    address= rhs_.address;
    write= rhs_.write;
    xtn_type= rhs_.xtn_type;
    xtn_delay= rhs_.xtn_delay;
 
  endfunction:do_copy

here in this do_copy, i am just copying the same type of transaction into another same type object then why i need to do $cast??

 

[dave_59]

I explained this **broken link removed**.

 

[Maulik Suthar]

still i am not clear with the do_copy function, i will be glad if u elaborate a little
thank u