Suspend execution of R expressions for a specified time interval.
The time interval to suspend execution for, in seconds.
Using this function allows R to temporarily be given very low
priority and hence not to interfere with more important foreground
tasks. A typical use is to allow a process launched from R to set
itself up and read its input files before R execution is resumed.
The intention is that this function suspends execution of R
expressions but wakes the process up often enough to respond to GUI
events, typically every half second. It can be interrupted
(e.g.by Ctrl-C or Esc at the R console).
There is no guarantee that the process will sleep for the whole of the
specified interval (sleep might be interrupted), and it may well take
slightly longer in real time to resume execution.
time must be non-negative (and not NA nor NaN):
Inf is allowed (and might be appropriate if the intention is to
wait indefinitely for an interrupt). The resolution of the time
interval is system-dependent, but will normally be 20ms or better.
(On modern Unix-alikes it will be better than 1ms.)