...
wait4(28813, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 28813
--- SIGCHLD (Child exited) @ 0 (0) ---
rt_sigreturn(0)                         = 28813
rt_sigaction(SIGINT, {SIG_DFL}, NULL, 8) = 0
rt_sigaction(SIGQUIT, {SIG_DFL}, NULL, 8) = 0
read(6, "", 4)                          = 0
close(6)                                = 0
rt_sigprocmask(SIG_BLOCK, [CHLD], NULL, 8) = 0
wait4(-1, 0x7fff3bda0c04, 0, NULL)      = -1 ECHILD (No child processes)
write(1, "_lostChild args:\n", 17)      = 17
write(1, "$VAR1 = [\n          -1\n        ]"..., 34) = 34
write(1, "\n", 1)                       = 1
rt_sigprocmask(SIG_UNBLOCK, [CHLD], NULL, 8) = 0
write(2, "rc=0\n", 5)                   = 5
close(4)                                = 0
exit_group(0)                           = ?