Sync_to_pps

Hello,
I recently purchased a USRP2 and have been trying to find the
documentation/examples on how to use the PPS functionality to timestamp
received data (with the PPS connected to a 1sec trigger source). So far,
I
have not been able to find any examples of using this functionality. If
I am
starting off, should I use the libusb2 or use the usrp2-vrt mode to use
the
timestamp functionality? Any examples/documentation to get started using
these would be useful.

Thanks
Subbu M.