No Cardiopulmonary Resuscitation/support and comfort only

I tried to find the No Cardiiopulmonary Resuscitation form as directed on the form being www.health.gov.bc.ca/exforms/bcas/302.1fil.pdf.  It wasn't there.  However I found it at www2.gov.bc.ca Forms for Medical and Health Care Practioners under miscellaneous form #3021 No Cardiopulmonary Resuscitation (PDF, 675KB). 

What concerns me is the declaration signed by the patient:

I, the patient, understand and accept that I have been diagnosed as having a life-limiting illness or am considered to be at the natural end of my life and that my care is to include support and comfort only and that no cardiopulmonary resuscitation is to be undertaken. 

What does this mean.  Does this mean that a patient refuses agressive medical treatment when he agrees to a DNR.
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