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   The Penguin of Evil (etchedpixels@mastodon.social)'s status on Wednesday, 11-Dec-2024 09:55:48 JST The Penguin of Evil

   Bizzare Unix semantics question. Given the parent of init is init (getppid(() of pid 1 is 1) is init the child of init, and if only init is running what is the correct return from wait(NULL);

   Believe it or not I actually found a case it matters in my Fuzix init today and having read various docs I'm really not sure what the answer is. ECHILD or blocking ?

   #unix #fuzix #retrocomputing

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     The Penguin of Evil (etchedpixels@mastodon.social)'s status on Wednesday, 11-Dec-2024 09:55:58 JST The Penguin of Evil

     in reply to

     • Leah Neukirchen

     @leah Unix V7 seems to sleep.

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     Leah Neukirchen (leah@blahaj.social)'s status on Wednesday, 11-Dec-2024 09:55:59 JST Leah Neukirchen

     in reply to

     @etchedpixels I doubt you find any system that doesn't return ECHILD?

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     Leah Neukirchen (leah@blahaj.social)'s status on Wednesday, 11-Dec-2024 09:56:30 JST Leah Neukirchen

     in reply to

     @etchedpixels I think it changed in 4.3 when https://github.com/dspinellis/unix-history-repo/commit/baffb38b8143b1a9fb9b8f85315071b0931617fd introduced an explicit list of child processes, where pid 1 doesn't include itself.

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     The Penguin of Evil (etchedpixels@mastodon.social)'s status on Wednesday, 11-Dec-2024 09:56:31 JST The Penguin of Evil

     in reply to

     • Leah Neukirchen

     @leah V7 has wait() only not waitpid(). The dozen other wait() with extras before waitpid() are all later things

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     Leah Neukirchen (leah@blahaj.social)'s status on Wednesday, 11-Dec-2024 09:56:31 JST Leah Neukirchen

     in reply to

     @etchedpixels it sleeps indeed, the code is easy to check. I'm very sure Linux does not.

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     Leah Neukirchen (leah@blahaj.social)'s status on Wednesday, 11-Dec-2024 09:56:32 JST Leah Neukirchen

     in reply to

     @etchedpixels does it have waitpid already? can you waitpid(1, &status, 0)?