What is the meaning of next code?

SystemVerilog
1

Hello VA,


class rate_coverage #(int unsigned TRACKING_WIN_LEN = 100) extends uvm_object;
    `uvm_object_utils(rate_coverage)

    bit xfer_num [$:TRACKING_WIN_LEN-1];
....

I cannot understand the syntax of: bit xfer_num [$:TRACKING_WIN_LEN-1];
What the indices mean?

Thanks,
Michael

2

In reply to Michael54:

This is a queue with a maximum size. See section 7.10 Queues in the IEEE 1800-2017 SystemVerilog LRM