h2o.mktime(
  year = 1970,
  month = 0,
  day = 0,
  hour = 0,
  minute = 0,
  second = 0,
  msec = 0
)

## Not run: 
library(h2o)
h2o.init()

x = as.h2o(c(2018, 3, 2, 6, 32, 0, 0))
h2o.mktime(x)

## End(Not run)