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Re: Safe accesses of global arrays in signal handlers?

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From	Nobody <nobody@nowhere.com>
Subject	Re: Safe accesses of global arrays in signal handlers?
Date	Thu, 27 Sep 2012 13:35:55 +0100
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On Thu, 27 Sep 2012 11:20:14 +0200, Markus Elfring wrote:

>> The recommended way to handle signals is to block all relevant async
>> signals in all threads, then have a single thread which does nothing but
>> poll signals using sigwaitinfo() then handle them (e.g. by notifying
>> condition variables, appending information to a queue, etc).
> 
> Do you know any other solutions which can work without such an initial signal
> blockage like it is needed in the suggested approach for the handling of
> real-time systems?

Doing anything substantial in a signal handler is problematic. So
typically you just want to notify a thread which blocks until
notification. There are a few async-signal-safe functions which can be
used for notification, including sem_post(), sigqueue(), raise() and
write(). A complete list is at:

http://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04_03

Note that none of the pthread functions are in that list.

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Thread

Safe accesses of global arrays in signal handlers? Markus Elfring <Markus.Elfring@web.de> - 2012-09-25 08:01 +0200
  Re: Safe accesses of global arrays in signal handlers? Nobody <nobody@nowhere.com> - 2012-09-25 12:15 +0100
    Re: Safe accesses of global arrays in signal handlers? Markus Elfring <Markus.Elfring@web.de> - 2012-09-27 11:20 +0200
      Re: Safe accesses of global arrays in signal handlers? Rainer Weikusat <rweikusat@mssgmbh.com> - 2012-09-27 13:23 +0100
        Re: Safe accesses of global arrays in signal handlers? Markus Elfring <Markus.Elfring@web.de> - 2012-09-28 13:25 +0200
      Re: Safe accesses of global arrays in signal handlers? Nobody <nobody@nowhere.com> - 2012-09-27 13:35 +0100
        Re: Safe accesses of global arrays in signal handlers? Markus Elfring <Markus.Elfring@web.de> - 2012-09-28 13:48 +0200
          Re: Safe accesses of global arrays in signal handlers? Johann Klammer <klammerj@NOSPAM.a1.net> - 2012-09-28 18:34 +0200
            Re: Safe accesses of global arrays in signal handlers? scott@slp53.sl.home (Scott Lurndal) - 2012-09-28 17:54 +0000
          Re: Safe accesses of global arrays in signal handlers? Nobody <nobody@nowhere.com> - 2012-09-28 18:26 +0100
            Re: Safe accesses of global arrays in signal handlers? Markus Elfring <Markus.Elfring@web.de> - 2012-09-29 13:44 +0200
              Re: Safe accesses of global arrays in signal handlers? Nobody <nobody@nowhere.com> - 2012-09-29 20:37 +0100
                Re: Safe accesses of global arrays in signal handlers? William Ahern <william@wilbur.25thandClement.com> - 2012-09-29 17:31 -0700
                Signal handlers writing into pipes Markus Elfring <Markus.Elfring@web.de> - 2012-09-30 13:21 +0200
                Re: Safe accesses of global arrays in signal handlers? Rainer Weikusat <rweikusat@mssgmbh.com> - 2012-10-01 18:04 +0100
                Signal handlers writing into pipes Markus Elfring <Markus.Elfring@web.de> - 2012-10-03 16:36 +0200
                Re: Signal handlers writing into pipes Rainer Weikusat <rweikusat@mssgmbh.com> - 2012-10-03 17:07 +0100
                Re: Safe accesses of global arrays in signal handlers? Markus Elfring <Markus.Elfring@web.de> - 2012-09-30 13:12 +0200
                Re: Safe accesses of global arrays in signal handlers? Nobody <nobody@nowhere.com> - 2012-09-30 20:46 +0100
        Re: Safe accesses of global arrays in signal handlers? Geoff Clare <geoff@clare.See-My-Signature.invalid> - 2012-09-28 13:39 +0100
        Re: Safe accesses of global arrays in signal handlers? Markus Elfring <Markus.Elfring@web.de> - 2012-09-29 13:15 +0200
          Re: Safe accesses of global arrays in signal handlers? William Ahern <william@wilbur.25thandClement.com> - 2012-09-29 17:42 -0700
            Re: Safe accesses of global arrays in signal handlers? Markus Elfring <Markus.Elfring@web.de> - 2012-09-30 14:04 +0200
  Re: Safe accesses of global arrays in signal handlers? Rainer Weikusat <rweikusat@mssgmbh.com> - 2012-09-25 13:27 +0100

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