A process can suspend execution until any of its child processes terminate using the
<emphasis>wait
</emphasis> system call, which returns the PID and exit status of the terminated child process. A parent process can arrange to be notified by a signal when a child process exits or terminates abnormally. Using the
<emphasis>wait4
</emphasis> system call, the parent can retrieve information about the event that caused termination of the child process and about resources consumed by the process during its lifetime. If a process is orphaned because its parent exits before it is finished, then the kernel arranges for the child's exit status to be passed back to a special system process
<emphasis>init
</emphasis>: see Sections 3.1 and 14.6).