Suspend Execution for a Time Interval

Description

Suspend execution of R expressions for a given number of seconds

Usage

Sys.sleep(time)

Arguments

Details

Using this function allows R to 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 0.5 seconds.

There is no guarantee that the process will sleep for the whole of the specified interval, and it may well take slightly longer in real time to resume execution. The resolution of the time interval is system-dependent, but will normally be down to 0.02 secs or better. (On modern Unix-alikes it will be better than 1ms.)

Value

Invisible NULL.

Note

This function may not be implemented on all systems. Where it is not implemented calling it given an error.

Examples

testit <- function(x)
{
    p1 <- proc.time()
    Sys.sleep(x)
    proc.time() - p1 # The cpu usage should be negligible
}
testit(3.7)