Messages in this thread | | | Subject | Re: SIGCHLD and SIG_IGN | Date | Tue, 24 Nov 1998 22:23:11 -0500 | From | "Brandon S. Allbery KF8NH" <> |
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In message <19981124114448.A302@perlsupport.com>, Chip Salzenberg writes: +----- | According to H. J. Lu: | > I was told the behavior of | > signal(SIGCHLD, SIG_IGN) | > is totally undefined under POSIX. | | Even if that's so, Linux is fortunately in the camp of "doing things | as they've always been done" in its current handling of SIGCHLD and | SIG_IGN. The auto-reaping behavior probably goes all the way back to | Unix V7, because both BSD and System V do it. +--->8
...differently. Which is why POSIX washed its hands of the issue.
Version 7 didn't have SIGCH?LD, much less magic behavior for SIG_DFL and SIG_IGN.
Linux, as usual, has the System III/V-style semantics for SIGCLD. The BSD SIGCHLD semantics are (somewhat subtly) different, which causes programs that expect BSD SIGCHLD behavior to break under Linux (and on System III/V and derivatives) with the exact symptom seen here.
-- brandon s. allbery [os/2][linux][solaris][japh] allbery@kf8nh.apk.net system administrator [WAY too many hats] allbery@ece.cmu.edu carnegie mellon / electrical and computer engineering KF8NH Kiss my bits, Billy-boy.
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