1SemaphoreSet(3)       User Contributed Perl Documentation      SemaphoreSet(3)
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NAME

6       Coro::SemaphoreSet - efficient set of counting semaphores
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SYNOPSIS

9        use Coro;
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11        $sig = new Coro::SemaphoreSet [initial value];
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13        $sig->down ("semaphoreid"); # wait for signal
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15        # ... some other "thread"
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17        $sig->up ("semaphoreid");
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DESCRIPTION

20       This module implements sets of counting semaphores (see
21       Coro::Semaphore). It is nothing more than a hash with normal semaphores
22       as members, but is more efficiently managed.
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24       This is useful if you want to allow parallel tasks to run in parallel
25       but not on the same problem. Just use a SemaphoreSet and lock on the
26       problem identifier.
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28       You don't have to load "Coro::SemaphoreSet" manually, it will be loaded
29       automatically when you "use Coro" and call the "new" constructor.
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31       new [initial count]
32           Creates a new semaphore set with the given initial lock count for
33           each individual semaphore. See Coro::Semaphore.
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35       $semset->down ($id)
36           Decrement the counter, therefore "locking" the named semaphore.
37           This method waits until the semaphore is available if the counter
38           is zero.
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40       $semset->up ($id)
41           Unlock the semaphore again. If the semaphore reaches the default
42           count for this set and has no waiters, the space allocated for it
43           will be freed.
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45       $semset->try ($id)
46           Try to "down" the semaphore. Returns true when this was possible,
47           otherwise return false and leave the semaphore unchanged.
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49       $semset->count ($id)
50           Return the current semaphore count for the specified semaphore.
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52       $semset->waiters ($id)
53           Returns the number (in scalar context) or list (in list context) of
54           waiters waiting on the specified semaphore.
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56       $semset->wait ($id)
57           Same as Coro::Semaphore::wait on the specified semaphore.
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59       $guard = $semset->guard ($id)
60           This method calls "down" and then creates a guard object. When the
61           guard object is destroyed it automatically calls "up".
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63       $semaphore = $semset->sem ($id)
64           This SemaphoreSet version is based on Coro::Semaphore's. This
65           function creates (if necessary) the underlying Coro::Semaphore
66           object and returns it. You may legally call any Coro::Semaphore
67           method on it, but note that calling "$semset->up" can invalidate
68           the returned semaphore.
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AUTHOR/SUPPORT/CONTACT

71          Marc A. Lehmann <schmorp@schmorp.de>
72          http://software.schmorp.de/pkg/Coro.html
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76perl v5.28.0                      2017-08-31                   SemaphoreSet(3)