Time is expressed as seconds since some arbitrary time in the past; it is not correlated in any way to the time of day, and thus is not subject to resetting or drifting. The hi-res timer is ideally suited to performance measurement tasks, where cheap, accurate interval timing is required.
hires_time()
hires_time()#> [1] 1583887533# R rounds doubles to 7 digits by default, see greater precision by setting # the digits argument when printing print(hires_time(), digits = 20)#> [1] 1583887533.041084528# Generally used by recording two times and then subtracting them start <- hires_time() end <- hires_time() elapsed <- end - start elapsed#> [1] 0.0009338856