# Problem in unique of Constraint Randomization

**URL:** <https://verificationacademy.com/forums/t/problem-in-unique-of-constraint-randomization/31769>\
**Category:** SystemVerilog\
**Tags:** SystemVerilog, constraint, unique\
**Created:** [April 29, 2016, 5:31am UTC](https://verificationacademy.com/forums/t/problem-in-unique-of-constraint-randomization/31769 "2016-04-29T05:31:46Z")\
**Posts on this page:** 1\
**Showing post:** 5

<div class="post-metadata">

**Author:** ![Huzefa\_Halolwala](https://verificationacademy.com/forums/letter_avatar_proxy/v4/letter/h/e47774/32.png) [@Huzefa\_Halolwala](https://verificationacademy.com/forums/u/Huzefa_Halolwala)\
**Post date:** [April 29, 2016, 6:02am UTC](https://verificationacademy.com/forums/t/problem-in-unique-of-constraint-randomization/31769/5 "2016-04-29T06:02:23Z")

</div>

_In reply to [sharvil111](https://verificationacademy.com/forums/t/problem-in-unique-of-constraint-randomization/31769/4):_  
Yes, I am using the VCS tool only and here is my code:  
module test();

class Packet;

rand byte a,b[10],c;  
constraint ab {unique {a,b[2:5],c};}  
constraint c1{c==5;}  
endclass

Packet p=new();

initial begin

repeat(10)

```
if(p.randomize()) $display("%p",p);

```

endmodule

Output:

“file.sv”, 8: token is ‘unique’  
constraint ab {unique {a,b[2:5],c};}  
^  
System verilog keyword ‘unique’ is not expected to be used in this context.

---

_[View the full topic](https://verificationacademy.com/forums/t/problem-in-unique-of-constraint-randomization/31769)._