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# core.sync.mutex

The `mutex` module provides a primitive for maintaining mutually exclusive access.
License:
Boost License 1.0
Authors:
Sean Kelly

Source: core/sync/mutex.d

class `Mutex`: object.Object.Monitor;
  This class represents a general purpose, recursive mutex.
  Implemented using pthread_mutex on Posix and CRITICAL_SECTION on Windows.
  Examples:

      import core.thread : Thread;

      class Resource
      {
          Mutex mtx;
          int cargo;

          this() shared @safe nothrow
          {
              mtx = new shared Mutex();
              cargo = 42;
          }

          void useResource() shared @safe nothrow @nogc
          {
              mtx.lock_nothrow();
              cargo++;
              mtx.unlock_nothrow();
          }
      }

      shared Resource res = new shared Resource();

      auto otherThread = new Thread(
      {
          foreach (i; 0 .. 10000)
              res.useResource();
      }).start();

      foreach (i; 0 .. 10000)
          res.useResource();

      otherThread.join();

      assert (res.cargo == 20042);

  nothrow @nogc @trusted this();
  shared nothrow @nogc @trusted this();
    Initializes a mutex object.
  nothrow @nogc @trusted this(Object `obj`);
  shared nothrow @nogc @trusted this(Object `obj`);
    Initializes a mutex object and sets it as the monitor for `obj`.

    In: `obj` must not already have a monitor.

  @trusted void `lock`();
  shared @trusted void `lock`();
  final nothrow @nogc @trusted void `lock_nothrow`(this Q)()
  if (is(Q == Mutex) || is(Q == shared(Mutex)));
    If this `lock` is not already held by the caller, the `lock` is acquired, then the internal counter is incremented by one.

    Note: Mutex.`lock` does not throw, but a class derived from Mutex can throw. Use `lock_nothrow` in nothrow @nogc code.

  @trusted void `unlock`();
  shared @trusted void `unlock`();
  final nothrow @nogc @trusted void `unlock_nothrow`(this Q)()
  if (is(Q == Mutex) || is(Q == shared(Mutex)));
    Decrements the internal lock count by one. If this brings the count to zero, the lock is released.

    Note: Mutex.`unlock` does not throw, but a class derived from Mutex can throw. Use `unlock_nothrow` in nothrow @nogc code.

  @trusted bool `tryLock`();
  shared @trusted bool `tryLock`();
  final nothrow @nogc @trusted bool `tryLock_nothrow`(this Q)()
  if (is(Q == Mutex) || is(Q == shared(Mutex)));
    If the lock is held by another caller, the method returns. Otherwise, the lock is acquired if it is not already held, and then the internal counter is incremented by one.
    Returns:
    `true` if the lock was acquired and `false` if not.

    Note: Mutex.`tryLock` does not throw, but a class derived from Mutex can throw. Use `tryLock_nothrow` in nothrow @nogc code.

Copyright © 1999-2017 by the D Language Foundation | Page generated by Ddoc on Thu Aug 10 17:50:47 2017