Thread::Mutex

Thread::Mutex implements a simple semaphore that can be used to coordinate access to shared data from multiple concurrent threads.

Example:

semaphore = Thread::Mutex.new

a = Thread.new {
  semaphore.synchronize {
    # access shared resource
  }
}

b = Thread.new {
  semaphore.synchronize {
    # access shared resource
  }
}

Class Methods

Thread::Mutex.new → mutex

4.0 View on GitHub

          # File tmp/rubies/ruby-4.0.0/thread_sync.rb, line 76
def initialize
end

Creates a new Mutex

Instance Methods

mutex.lock → self

4.0 View on GitHub

          # File tmp/rubies/ruby-4.0.0/thread_sync.rb, line 100
def lock
  Primitive.rb_mut_lock
end

Attempts to grab the lock and waits if it isn’t available. Raises ThreadError if mutex was locked by the current thread.

mutex.locked? → true or false

4.0 View on GitHub

          # File tmp/rubies/ruby-4.0.0/thread_sync.rb, line 83
def locked?
  Primitive.cexpr! %q{ RBOOL(mutex_locked_p(mutex_ptr(self))) }
end

Returns true if this lock is currently held by some thread.

mutex.owned? → true or false

4.0 View on GitHub

          # File tmp/rubies/ruby-4.0.0/thread_sync.rb, line 91
def owned?
  Primitive.rb_mut_owned_p
end

Returns true if this lock is currently held by current thread.

mutex.sleep(timeout = nil) → number or nil

4.0 View on GitHub

          # File tmp/rubies/ruby-4.0.0/thread_sync.rb, line 147
def sleep(timeout = nil)
  Primitive.rb_mut_sleep(timeout)
end

Releases the lock and sleeps timeout seconds if it is given and non-nil or forever. Raises ThreadError if mutex wasn’t locked by the current thread.

When the thread is next woken up, it will attempt to reacquire the lock.

Note that this method can wakeup without explicit Thread#wakeup call. For example, receiving signal and so on.

Returns the slept time in seconds if woken up, or nil if timed out.

mutex.synchronize { ... } → result of the block

4.0 View on GitHub

          # File tmp/rubies/ruby-4.0.0/thread_sync.rb, line 127
def synchronize
  raise ThreadError, "must be called with a block" unless defined?(yield)

  Primitive.rb_mut_synchronize
end

Obtains a lock, runs the block, and releases the lock when the block completes. See the example under Thread::Mutex.

mutex.try_lock → true or false

4.0 View on GitHub

          # File tmp/rubies/ruby-4.0.0/thread_sync.rb, line 109
def try_lock
  Primitive.rb_mut_trylock
end

Attempts to obtain the lock and returns immediately. Returns true if the lock was granted.

mutex.lock → self

4.0 View on GitHub

          # File tmp/rubies/ruby-4.0.0/thread_sync.rb, line 118
def unlock
  Primitive.rb_mut_unlock
end

Attempts to grab the lock and waits if it isn’t available. Raises ThreadError if mutex was locked by the current thread.