Messages in this thread |  | | Date | Mon, 3 Jun 1996 14:53:16 -0600 (MDT) | From | Marc Aurele La France <> | Subject | On SIGCHLD signal semantics |
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Good day.
This is the readme file for tsi.sigchld.diff.gz which has been uploaded to ftp://ftp.lmh.ox.ac.uk/incoming.
This change does not affect any kernel functionality. What it does do however is introduce warnings under certain circumstances with respect to SIGCHLD signal semantics. The circumstances addressed are when a parent process decides to wait for termination of one of its child processes, but does so with its SIGCHLD signal handler set to SIG_IGN. If the child process terminates while its parent is waiting, this is not a problem. But if the child terminates before the parent waits, then the parent will be told it has no children (because the kernel has already gotten rid of any indication of the child's existence). This can confuse the parent process.
Documentation/sigchld.txt, which is inserted by this change, comments on this situation more thoroughly and should be consulted for details.
So far, I have been unsuccessful at digging up what various standards such as POSIX have to say about this case. So, I am hoping that someone on this list will point me to an already existing solution to this problem (and thus tell me whether I am out to lunch on this one :-)).
Replies welcome.
Marc.
+----------------------------------+-----------------------------------+ | Marc Aurele La France | work: 1-403-492-9310 | | Computing and Network Services | fax: 1-403-492-1729 | | 352 General Services Building | email: tsi@ualberta.ca | | University of Alberta +-----------------------------------+ | Edmonton, Alberta | | | T6G 2H1 | Standard disclaimers apply | | CANADA | | +----------------------------------+-----------------------------------+
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