status of the command as returned by wait4 (2). RETURN VALUE popen (): on success, returns ... exit status of the command; if wait4 (2) returns an error, or some other errorstatus of the command as returned by wait4 (2). RETURN VALUE popen (): on success, returns ... exit status of the command; if wait4 (2) returns an error, or some other errorgetrlimit (2), times (2), wait (2), wait4 (2), clock (3), proc_pid_stat (5), proc