Module: PThread

Extended by:

FFI::Library, Helper

Included in:

Mutex, MutexAttr

Defined in:

lib/scratch.rb

Defined Under Namespace

Modules: Helper Classes: Int, Mutex, MutexAttr

Constant Summary

Constants included from Helper

Helper::MAP_FAILED, Helper::MAP_PRIVATE, Helper::MAP_SHARED, Helper::O_CREAT, Helper::O_RDWR, Helper::PROT_EXEC, Helper::PROT_NONE, Helper::PROT_READ, Helper::PROT_WRITE, Helper::PTHREAD_PROCESS_SHARED

Class Method Summary

• .call(err_msg = 'error in pthreads', &block) ⇒ Object
• .test ⇒ Object

Class Method Details

.call(err_msg = 'error in pthreads', &block) ⇒ Object

Raises:

• (SystemCallError)

# File 'lib/scratch.rb', line 122

def call(err_msg = 'error in pthreads', &block)
  ret = yield
  raise SystemCallError.new(err_msg, ret) unless ret == 0
end

.test ⇒ Object

# File 'lib/scratch.rb', line 248

def test
  puts "hi #{Helper.sizeof_pthread_mutex_t}"
  puts Mutex.new


  fd = LibC.call { RT.shm_open("/foo", O_CREAT | O_RDWR, 0777) }
  LibC.call { LibC.ftruncate(fd, 100) }
  pointer = LibC.mmap(nil, 100, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0)
  puts pointer
  puts pointer == MAP_FAILED
  puts MAP_FAILED

  attr = MutexAttr.new
  attr.pshared = PTHREAD_PROCESS_SHARED

  mutex = Mutex.new(pointer, attr.pointer)


  fd = LibC.call { RT.shm_open("/someint", O_CREAT | O_RDWR, 0777) }
  LibC.call { LibC.ftruncate(fd, 100) }
  pointer = LibC.mmap(nil, 100, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0)
  abort "failed" if pointer == MAP_FAILED

  value = Int.new(pointer)
  value[:val] = 0
  puts "int[0]: #{value[:val]}"

  puts "parent has mutex #{mutex}"

  n = 10000

  child = fork do
    puts "child and I have mutex: #{mutex}"

    n.times do |i|
      mutex.lock
      value[:val] = (value[:val] + 1)
      mutex.unlock
    end
  end

  n.times do |i|
    mutex.lock
    value[:val] = (value[:val] + 1)
    mutex.unlock
  end

  Process.wait(child)

  puts "value is now #{value[:val]}"
end