In reply to ziggy:
$cast does not create or copy objects; it tries to copy a handle from one class variable to another. Please see my course on SystemVerilog OOP, especially the second session.
In reply to dave_59:
So in the above code I have posted, Class A’s handle ‘a’ is created by ‘new’. Then I do a $cast(b,a). Why is there an error ‘type mismatch’?
But the following code works and why is that?
class A;
int a=10;
virtual function void disp();
$display("Base a=%d",a);
endfunction
endclass
class B extends A;
int a=20;
function void disp();
$display("Derived a=%d",a);
endfunction
endclass
module tb();
A a;
B b=new;
initial begin
b=a;
$cast(b,a);
b.disp(); //
$display("b.a=%d",b.a); //
a.disp(); //
$display("a.a=%d",a.a); //
end
endmodule
In reply to ziggy:
The code you just posted does not work. Did you simulate it?
b=a; // should give you a compile error
b.disp(); // should be a run time fatal because b has a null handle.
In reply to dave_59:
Sorry it was a typo
Its “a=b” and not “b=a”
In reply to ziggy:
Have you looked at my course yet?
In reply to dave_59:
Hi Dave,
Your sv-class-OOP courses are excellent !! Heavily loaded with important information. The way you described all of them seamlessly is awesome!
Hi Dave,
can you share more courses… how we can access them