Sys.sleep                package:base                R Documentation

Suspend Execution for a Time Interval

Description:

     Suspend execution of R expressions for a given number of seconds

Usage:

     Sys.sleep(time)

Arguments:

    time: The time interval to suspend execution for, in seconds.

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.

Examples:

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

