--- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=21521, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
--- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=21518, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
--- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=21520, si_uid=0, si_status=0, si_utime=0, si_stime=2 /* 0.02 s */} ---
--- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=21517, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
+++ exited with 0 +++