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copied!<p>You'll want to learn about interacting with the /proc/ "psuedo-filesystem" via typical C standard library calls. The documentation necessary to get started is included with any Linux distro and is a simple google search away.</p> <p>(Now that you know what to search for. I know that's usually most of the challenge!)</p> <p>In short, the directories and files within the /proc/ directory of a running Linux system reflect the state of the running kernel, which (naturally) includes processes. However, before you charge in you need to keep some information in mind.</p> <p>A zombie process isn't the same thing as an orphaned process. An orphaned process is a process left running in a waiting state after the process' parent has exited incorrectly. A zombie process is a process which has exited properly, released all its resources, but is maintaining a place in the process table.</p> <p>This typically happens when a process is launched by a program. You see, the kernel won't remove a finished sub-process' entry in the process table until the parent program properly fetches the return status of the sub-process. That makes sense; how else would the parent program know if the subprocess exited improperly?</p> <p>So all subprocesses are technically zombies for at least a very short time. It's not inherently a bad state for a program to be in.</p> <p>Indeed, "zombies" are sometimes created intentionally. For example, sometimes a zombie entry is left in place by a program for a while so that further launched processes won't get the same PID as the previously-launched (and now zombie) process.</p> <p>In other words, if you go SIGCHLDing zombie processes unnecessarily you might create a serious problem for the spawning program. However, if a process has been a zombie for a half hour or more, it's probably a sign of a bug.</p> <p>Edit: The question changed on me! No, there's no simpler way than how ps does it. If there was, it would have been integrated into ps a long time ago. The /proc files are the be-all-end-all source for information on the kernel's state. :)</p>

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