Suspend execution for an interval (POSIX)
QNX Neutrino, Linux, Microsoft Windows
As a QNX Neutrino extension, time can be a floating point number, so you can specify fractions of seconds.
The sleep utility suspends execution for at least the number of seconds specified by the time operand.
The sleep utility takes the default action for all signals, except that sleep terminates normally with a zero exit status on receipt of a SIGALRM signal.