Class: ProcessShared::BoundedSemaphore

Inherits:
Semaphore show all
Defined in:
lib/process_shared/bounded_semaphore.rb

Overview

BoundedSemaphore is identical to Semaphore except that its value is not permitted to rise above a maximum. When the value is at the maximum, calls to #post will have no effect.

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Semaphore

#close, #post, #value, #wait

Methods inherited from AbstractSemaphore

gen_name, make_finalizer

Methods included from PSem

psem_error_check

Methods included from DefineSingletonMethod

#define_singleton_method

Methods included from WithSelf

#with_self

Constructor Details

#initialize(maxvalue, value = 1, name = nil) ⇒ BoundedSemaphore

Create a new semaphore with initial value ‘value`. After Kernel#fork, the semaphore will be shared across two (or more) processes. The semaphore must be closed with #close in each process that no longer needs the semaphore.

(An object finalizer is registered that will close the semaphore to avoid memory leaks, but this should be considered a last resort).

Parameters:

  • value (Integer) (defaults to: 1) —

    the initial semaphore value

  • name (String) (defaults to: nil) —

    not currently supported



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# File 'lib/process_shared/bounded_semaphore.rb', line 32

def initialize(maxvalue, value = 1, name = nil)
  init(PSem.sizeof_bsem_t, 'bsem', name) do |sem_name|
    bsem_open(sem, sem_name, maxvalue, value, err)
  end
end

Class Method Details

.open(maxvalue, value = 1, name = nil, &block) ⇒ Object

With no associated block, open is a synonym for Semaphore.new. If the optional code block is given, it will be passed ‘sem` as an argument, and the Semaphore object will automatically be closed when the block terminates. In this instance, Semaphore.open returns the value of the block.

Parameters:

  • value (Integer) (defaults to: 1) —

    the initial semaphore value

  • name (String) (defaults to: nil) —

    not currently supported



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# File 'lib/process_shared/bounded_semaphore.rb', line 17

def self.open(maxvalue, value = 1, name = nil, &block)
  new(maxvalue, value, name).with_self(&block)
end