survival in SAS vs R

[vsing...@gmail.com]

Here is some code we were using in SAS:

proc phreg data=a;
model (start,stop)*event(0)=age/ ties=efron ;
age=start-stop;

We were guessing we might be able to use "coxph"
from the survival package in R to do the same test,
but we are not sure how to set age as a time
varying covariate.

In other words, age will increase as the model runs.
We want to determine if an increase in age leads
to a risk of failure.

If anyone can help us find the equivalent to this
in R, we would be greatly appreciative.