pcap_set_tstamp_precision() sets the precision of the time stamp desired for packets captured on the pcap
descriptor to the type specified by
tstamp_precision. It must be called on a pcap descriptor created by
pcap_create(3) that has not yet been activated by
pcap_activate(3) .
Two time stamp precisions are supported, microseconds and nanoseconds. One can
use options
PCAP_TSTAMP_PRECISION_MICRO and PCAP_TSTAMP_PRECISION_NANO to request desired precision. By default, time stamps are in microseconds.