# wait one second please
sleep 1

$ cd bash-3.2.48/examples/loadables
$ make sleep && mv sleep sleep.so
$ enable -f sleep.so sleep

$ which sleep
/usr/bin/sleep
$ builtin sleep
sleep: usage: sleep seconds[.fraction]
$ time (for f in `seq 1 10`; do builtin sleep 0.1; done)
real    0m1.000s
user    0m0.004s
sys     0m0.004s

[ -z "$BASH_LOADABLE_PATH" ] &&
  BASH_LOADABLES_PATH=$(pkg-config bash --variable=loadablesdir 2>/dev/null)
enable -f sleep sleep

$ perl -e "select(undef,undef,undef,0.1);"
$ echo "after 100" | tclsh

sleep 0.5

sleep 0.01

sleep 0.001

time sleep 0.5      # 500 milliseconds (1/2 of a second)
    time sleep 0.001    # 1 millisecond (1/1000 of a second)
    time sleep 1.0      # 1 second (1000 milliseconds)

usleep 1000

#include "stdio.h"
  int main(int argc, char **argv) {
     usleep(atoi(argv[1]));
     return 0;
}