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Re: counting_semaphore question

From Muttley@dastardlyhq.com
Newsgroups comp.lang.c++
Subject Re: counting_semaphore question
Date 2024-09-11 12:03 +0000
Organization A noiseless patient Spider
Message-ID <vbs0tm$3jf62$1@dont-email.me> (permalink)
References <vbrqjj$3hvsd$1@dont-email.me> <vbs01c$3j5mc$1@raubtier-asyl.eternal-september.org>

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On Wed, 11 Sep 2024 13:48:04 +0200
Bonita Montero <Bonita.Montero@gmail.com> boringly babbled:
>Am 11.09.2024 um 12:15 schrieb Muttley@dastardlyhq.com:
>> I've been looking at counting_semaphore and it looks useful but something
>> that doesn't seem to be properly explained anywhere is the template
>> parameter value. eg you can do:
>> 
>> std::counting_semaphore sem(2)
>> 
>> which will let a max of 2 threads into the protected block at a time or:
>> 
>> std::counting_semaphore<some number> sem(2)
>> 
>> such as
>> 
>> std::counting_semaphore<10> sem(2)
>> 
>> I don't understand what the '10' will do. ..
>
>The ten gives an upper limit beyond the semaphore wont't increment.

What upper limit? The max number of threads allowed in the protected section
above is 2, not 10. Or do you mean it'll only count up to 10 threads waiting
and ignore any beyond that? What happens if thread 11 comes along?

>Usually you won't need a C++20 semaphore yourself. For most purpose
>the mutex and the condition_variable is sufficient.

Condition variables IMO are unintuitive (eg the internal state change from
waiting on condition variable to waiting on mutex is completely invisible)
and hence very prone to logical bugs. I tend to avoid them where possible.

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counting_semaphore question Muttley@dastardlyhq.com - 2024-09-11 10:15 +0000
  Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-11 13:48 +0200
    Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-11 12:03 +0000
      Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-11 14:10 +0200
        Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-11 12:29 +0000
          Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-11 15:54 +0200
            Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-11 14:12 +0000
          Re: counting_semaphore question David Brown <david.brown@hesbynett.no> - 2024-09-11 16:23 +0200
            Re: counting_semaphore question "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-16 14:22 -0700
              Re: counting_semaphore question David Brown <david.brown@hesbynett.no> - 2024-09-17 09:22 +0200
                Re: counting_semaphore question "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-17 11:56 -0700
                Re: counting_semaphore question David Brown <david.brown@hesbynett.no> - 2024-09-18 09:32 +0200
                Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-19 12:57 +0200
                Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-19 13:01 +0200
                Re: counting_semaphore question "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-19 12:09 -0700
                Re: counting_semaphore question "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-19 13:27 -0700
                Re: counting_semaphore question "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-19 13:30 -0700
          Re: counting_semaphore question Ben Bacarisse <ben@bsb.me.uk> - 2024-09-12 11:25 +0100
            Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-12 11:00 +0000
              Re: counting_semaphore question Andrey Tarasevich <andreytarasevich@hotmail.com> - 2024-09-12 07:34 -0700
                Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-12 14:53 +0000
                Re: counting_semaphore question David Brown <david.brown@hesbynett.no> - 2024-09-13 08:39 +0200
                Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-13 07:26 +0000
                Re: counting_semaphore question David Brown <david.brown@hesbynett.no> - 2024-09-13 12:54 +0200
                Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-13 13:21 +0000
                Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-13 15:29 +0200
                Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-13 13:41 +0000
                Re: counting_semaphore question David Brown <david.brown@hesbynett.no> - 2024-09-15 17:33 +0200
                Re: counting_semaphore question David Brown <david.brown@hesbynett.no> - 2024-09-13 16:46 +0200
                Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-13 14:59 +0000
                Re: counting_semaphore question Andrey Tarasevich <andreytarasevich@hotmail.com> - 2024-09-13 07:43 -0700
        Re: counting_semaphore question "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-11 13:51 -0700
          Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-12 04:21 +0200
            Re: counting_semaphore question "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-12 11:57 -0700
              Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-13 14:29 +0200
                Re: counting_semaphore question "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-13 12:44 -0700
                Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-14 01:43 +0200
                Re: counting_semaphore question "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-13 22:21 -0700
                Re: counting_semaphore question "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-14 12:07 -0700
                Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-14 09:18 +0000
                Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-14 11:40 +0200
                Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-14 10:58 +0000
                Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-14 13:15 +0200
                Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-14 15:13 +0000
                Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-14 17:26 +0200
                Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-14 15:48 +0000
                Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-14 17:50 +0200
                Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-14 15:55 +0000
                Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-14 17:57 +0200
                Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-15 09:05 +0000
                Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-15 11:48 +0200
                Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-15 09:52 +0000
                Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-15 14:50 +0200
                Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-15 15:28 +0000
                Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-16 05:02 +0200
                Re: counting_semaphore question scott@slp53.sl.home (Scott Lurndal) - 2024-09-15 16:27 +0000
                Re: counting_semaphore question scott@slp53.sl.home (Scott Lurndal) - 2024-09-15 16:26 +0000
                Re: counting_semaphore question "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-14 12:12 -0700
                Re: counting_semaphore question "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-14 17:21 -0700
                Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-15 07:11 +0200
                Re: counting_semaphore question "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-14 22:20 -0700
                Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-15 09:35 +0200
                Re: counting_semaphore question "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-15 12:59 -0700
                Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-16 05:04 +0200
                Re: counting_semaphore question "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-16 13:30 -0700
                Re: counting_semaphore question "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-14 12:09 -0700
  Re: counting_semaphore question Andrey Tarasevich <andreytarasevich@hotmail.com> - 2024-09-11 07:37 -0700
    Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-11 15:03 +0000
      Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-11 17:27 +0200
        Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-11 16:04 +0000
          Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-11 18:16 +0200
            Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-11 18:16 +0000
              Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-12 04:20 +0200
          Re: counting_semaphore question "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-09-12 13:00 -0700
      Re: counting_semaphore question Andrey Tarasevich <andreytarasevich@hotmail.com> - 2024-09-11 20:56 -0700
        Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-12 07:43 +0000
          Re: counting_semaphore question David Brown <david.brown@hesbynett.no> - 2024-09-12 13:30 +0200
            Re: counting_semaphore question Muttley@dastardlyhq.com - 2024-09-12 14:48 +0000
          Re: counting_semaphore question Bonita Montero <Bonita.Montero@gmail.com> - 2024-09-12 15:38 +0200
          Re: counting_semaphore question Andrey Tarasevich <andreytarasevich@hotmail.com> - 2024-09-12 07:05 -0700

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