Orphan process and Zombie process: if the parent process exits first and the child process does not exit then the parent process of the child process becomes the INIT process (any process has a parent process) if the child process exits first and the parent process does not exit, the child process must wait until the parent process captures the exit state of the child process to really end, Otherwise, this time the subprocess becomes a zombie process. If the parent process ends first, the child process Tuogu to the number 1th process how to avoid the zombie process? is because the parent process did not give the child process corpse, how to solve this problem. When the parent process then creates the child process, it uses Singal (sigchild,sig_ing) to tell the kernel whether the child process's life cycle or not.
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Linux orphan process and zombie process