Monitor

Monitor class

Class Monitor provides a mechanism that synchronizes access to objects.

class Monitor : public System::Object

Methods

MethodDescription
static void Enter(const SharedPtr<Object>&)Acquires an exclusive lock on a specified object.
static void Enter(const System::SharedPtr<Object>&, bool&)Acquires an exclusive lock on the specified object, and atomically sets a value that indicates whether the lock was taken.
virtual bool Equals(ptr)Compares objects using C# Object.Equals semantics.
static std::enable_if<IsSmartPtr<T1>::value&&IsSmartPtr<T2>::value, bool>::type Equals(T1 const&, T2 const&)Compares reference type objects in C# style.
static std::enable_if<!IsSmartPtr<T1>::value&&!IsSmartPtr<T2>::value, bool>::type Equals(T1 const&, T2 const&)Compares value type objects in C# style.
static bool Equals(float const&, float const&)Emulates C#-style floating point comparison where two NaNs are considered equal even though according to IEC 60559:1989 NaN is not equal to any value, including NaN.
static bool Equals(double const&, double const&)Emulates C#-style floating point comparison where two NaNs are considered equal even though according to IEC 60559:1989 NaN is not equal to any value, including NaN.
static void Exit(const SharedPtr<Object>&)Releases an exclusive lock on the specified object.
virtual bool FastCast(const Details::FastRttiBase&, void **) constFor internal purposes only.
Detail::SmartPtrCounter * GetCounter()Gets reference counter data structure associated with the object.
virtual int32_t GetHashCode() constAnalog of C# Object.GetHashCode() method. Enables hashing of custom objects.
virtual const TypeInfo& GetType() constGets actual type of object. Analog of C# System.Object.GetType() call.
virtual bool Is(const TypeInfo&) constCheck if object represents an instance of type described by targetType. Analog of C# ‘is’ operator.
static bool IsEntered(const System::SharedPtr<Object>&)Determines whether the current thread holds the lock on the specified object.
void Lock()Implements C# lock() statement locking. Call directly or use LockContext sentry object.
virtual ptr MemberwiseClone() constAnalog of C# Object.MemberwiseClone() method. Enables cloning custom types.
Object()Creates object. Initializes all internal data structures.
Object(Object const&)Copy constructor. Doesn’t copy anything, really, just initializes new object and enables copy constructing subclasses.
Object& operator=(Object const&)Assignment operator. Doesn’t copy anything, really, just initializes new object and enables copy constructing subclasses.
static void Pulse(const SharedPtr<Object>&)Notifies a thread in the waiting queue of a change in the locked object’s state Not implemented.
static void PulseAll(const SharedPtr<Object>&)Notifies all waiting threads of a change in the object’s state Not implemented.
static bool ReferenceEquals(ptr const&, ptr const&)Compares objects by reference.
static std::enable_if<!IsSmartPtr<T>::value, bool>::type ReferenceEquals(T const&, T const&)Compares objects by reference.
static std::enable_if<!IsSmartPtr<T>::value, bool>::type ReferenceEquals(T const&, std::nullptr_t)Reference-compares value type object with nullptr.
bool ReferenceEquals(String const&, std::nullptr_t)Specialization of Object::ReferenceEquals for case of string and nullptr.
bool ReferenceEquals(String const&, String const&)Specialization of Object::ReferenceEquals for case of strings.
int RemovedSharedRefs(int)Decreases shared reference count by specified value.
virtual void SetTemplateWeakPtr(uint32_t)Set n’th template argument a weak pointer (rather than shared). Allows switching pointers in containers to weak mode.
int SharedCount() constGets current value of shared reference counter.
Object * SharedRefAdded()Increments shared reference count. Shouldn’t be called directly; instead, use smart pointers or ThisProtector.
int SharedRefRemovedSafe()Decrements and returns shared reference count. Shouldn’t be called directly; instead, use smart pointers or ThisProtector.
virtual String ToString() constAnalog of C# Object.ToString() method. Enables converting custom objects to string.
static bool TryEnter(const SharedPtr<Object>&)Attempts to acquire an exclusive lock on the specified object Not implemented.
static void TryEnter(const System::SharedPtr<Object>&, bool&)Attempts to acquire an exclusive lock on the specified object, and atomically sets a value that indicates whether the lock was taken.
static bool TryEnter(const SharedPtr<Object>&, int32_t)Attempts, for the specified number of milliseconds, to acquire an exclusive lock on the specified object Not implemented.
static bool TryEnter(const SharedPtr<Object>&, TimeSpan)Attempts, for the specified amount of time, to acquire an exclusive lock on the specified object Not implemented.
static void TryEnter(const System::SharedPtr<Object>&, int32_t, bool&)Attempts, for the specified amount of time, to acquire an exclusive lock on the specified object, and atomically sets a value that indicates whether the lock was taken.
static void TryEnter(const System::SharedPtr<Object>&, TimeSpan, bool&)Attempts, for the specified amount of time, to acquire an exclusive lock on the specified object, and atomically sets a value that indicates whether the lock was taken.
static const TypeInfo& Type()Implements C# typeof(System.Object) construct.
void Unlock()Implements C# lock() statement unlocking. Call directly or use LockContext sentry object.
static bool Wait(const SharedPtr<Object>&, int32_t, bool)Releases the lock on an object and blocks the current thread until it reacquires the lock. If the specified time-out interval elapses, the thread enters the ready queue. Optionally exits the synchronization domain for the synchronized context before the wait and reacquires the domain afterward. Not implemented.
static bool Wait(const SharedPtr<Object>&, TimeSpan, bool)Releases the lock on an object and blocks the current thread until it reacquires the lock. If the specified time-out interval elapses, the thread enters the ready queue. Optionally exits the synchronization domain for the synchronized context before the wait and reacquires the domain afterward. Not implemented.
static bool Wait(const SharedPtr<Object>&, int32_t)Releases the lock on an object and blocks the current thread until it reacquires the lock. If the specified time-out interval elapses, the thread enters the ready queue. Not implemented.
static bool Wait(const SharedPtr<Object>&, TimeSpan)Releases the lock on an object and blocks the current thread until it reacquires the lock. If the specified time-out interval elapses, the thread enters the ready queue. Not implemented.
static bool Wait(const SharedPtr<Object>&)Releases the lock on an object and blocks the current thread until it reacquires the lock Not implemented.
Detail::SmartPtrCounter * WeakRefAdded()Increments weak reference count. Shouldn’t be called directly; instead, use smart pointers or ThisProtector.
void WeakRefRemoved()Decrements weak reference count. Shouldn’t be called directly; instead, use smart pointers or ThisProtector.
virtual ~Object()Destroys object. Frees all internal data structures.

Remarks

#include "system/threading/monitor.h"
#include "system/threading/thread.h"
#include "system/smart_ptr.h"
#include "system/string.h"
#include <iostream>
#include <vector>

int main()
{
  using namespace System::Threading;

  const auto threadsCount = 3;
  std::cout << "Threads count: " << threadsCount << std::endl;
  auto locker = System::MakeObject<System::Object>();
  int x = 0;

  std::vector<System::SharedPtr<Thread>> threads;
  threads.reserve(threadsCount);
  for (auto i = 0; i < threadsCount; ++i)
  {
    threads.emplace_back(System::MakeObject<Thread>([&x, &locker]() -> void {
      Monitor::Enter(locker);

      x = 1;
      for (auto i = 0; i < 5; ++i)
      {
        std::cout << Thread::get_CurrentThread()->get_Name() << ": " << x++ << std::endl;
        Thread::Sleep(100);
      }

      Monitor::Exit(locker);
    }));
    threads.back()->set_Name(System::String("Thread " + std::to_string(i)));
    threads.back()->Start();
  }

  Thread::Sleep(threadsCount * 100);

  for (auto& thread : threads)
  {
    thread->Join();
  }

  return 0;
}
/*
This code example produces the following output:
Threads count: 3
Thread 0: 1
Thread 0: 2
Thread 0: 3
Thread 0: 4
Thread 0: 5
Thread 1: 1
Thread 1: 2
Thread 1: 3
Thread 1: 4
Thread 1: 5
Thread 2: 1
Thread 2: 2
Thread 2: 3
Thread 2: 4
Thread 2: 5
*/

See Also

ManualResetEvent Mutex