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class assignment

Multiple handles for the same object example

In the below example, memory is created for object tr1. Class handle tr2 can also point to the same object using a simple assignment operator.  After the assignment, anyone tr1 or tr2 handle can change the ‘data’ value.

class transaction;
  bit [31:0] data;

module class_example;
  transaction tr1, tr2;
  initial begin
    tr1 = new();
    tr1.data = 5;
    tr2 = tr1;
    $display("tr1.data = %0h", tr1.data);
    $display("tr2.data = %0h", tr2.data);
    tr2.data = 10;
    $display("tr1.data = %0h", tr1.data);
    $display("tr2.data = %0h", tr2.data);


tr1.data = 5
tr2.data = 5
tr1.data = a
tr2.data = a

Refer SystemVerilog Polymorphism to understand child class handle assignment to the base class and vice-versa.

System Verilog Tutorials