threading

Definition

Contains threading definitions.

Classes
class	xtd::threading::auto_reset_event
	Represents a thread synchronization event that, when signaled, resets automatically after releasing a single waiting thread. This class cannot be inherited. More...
class	xtd::threading::barrier
	Enables multiple tasks to cooperatively work on an algorithm in parallel through multiple phases. More...
class	xtd::threading::cancellation_token
	Propagates notification that operations should be canceled. More...
class	xtd::threading::cancellation_token_registration
	Propagates notification that operations should be canceled. More...
class	xtd::threading::cancellation_token_source
	Signals to a xtd::threading::cancellation_token that it should be canceled. More...
class	xtd::threading::countdown_event
	Represents a synchronization primitive that is signaled when its count reaches zero. More...
class	xtd::threading::event_wait_handle
	Represents a thread synchronization event. More...
class	xtd::threading::interlocked
	Provides atomic operations for variables that are shared by multiple threads. More...
class	xtd::threading::lock_guard
	Provides a mechanism that synchronizes access to objects with xtd::threading::monitor. More...
class	xtd::threading::manual_reset_event
	Represents a thread synchronization event that, when signaled, must be reset manually. This class cannot be inherited. More...
class	xtd::threading::monitor
	Provides a mechanism that synchronizes access to objects. More...
class	xtd::threading::mutex
	A synchronization primitive that can also be used for interprocess synchronization. More...
class	xtd::threading::registered_wait_handle
	A synchronization primitive that can also be used for interprocess synchronization. More...
class	xtd::threading::semaphore
	Limits the number of threads that can access a resource or pool of resources concurrently. More...
class	xtd::threading::spin_lock
	Provides a mutual exclusion lock primitive where a thread trying to acquire the lock waits in a loop repeatedly checking until the lock becomes available. More...
class	xtd::threading::thread
	Creates and controls a thread, sets its priority, and gets its status. More...
class	xtd::threading::thread_local_object< value_t >
	Provides thread-local storage of data. More...
class	xtd::threading::thread_pool
	Provides a pool of threads that can be used to execute tasks, post work items, process asynchronous I/O, wait on behalf of other threads, and process timers. More...
class	xtd::threading::timeout
	Contains a constant used to specify an infinite amount of time. This class cannot be inherited. More...
class	xtd::threading::timer
	Provides a mechanism for executing a method on a thread pool thread at specified intervals. This class cannot be inherited. More...
class	xtd::threading::wait_handle
	Encapsulates operating system specific objects that wait for exclusive access to shared resources. More...

Typedefs
using	xtd::lock = xtd::threading::lock_guard
	Provides a mechanism that synchronizes access to objects with xtd::threading::monitor.

Enumerations
enum class	xtd::threading::event_reset_mode {   xtd::threading::event_reset_mode::auto_reset ,   xtd::threading::event_reset_mode::manual_reset }
	Indicates whether an xtd::threading::event_wait_handle is reset automatically or manually after receiving a signal. More...
enum class	xtd::threading::thread_priority {   xtd::threading::thread_priority::lowest ,   xtd::threading::thread_priority::below_normal ,   xtd::threading::thread_priority::normal ,   xtd::threading::thread_priority::above_normal ,   xtd::threading::thread_priority::highest }
	Specifies the scheduling priority of a system::threading::thread. More...
enum class	xtd::threading::thread_state {   xtd::threading::thread_state::running ,   xtd::threading::thread_state::stop_requested ,   xtd::threading::thread_state::suspend_requested ,   xtd::threading::thread_state::background ,   xtd::threading::thread_state::unstarted ,   xtd::threading::thread_state::stopped ,   xtd::threading::thread_state::wait_sleep_join ,   xtd::threading::thread_state::suspended ,   xtd::threading::thread_state::abort_requested ,   xtd::threading::thread_state::aborted }
	Specifies the execution states of a System::Threading::Thread. More...

Typedef Documentation

lock

using xtd::lock = typedef xtd::threading::lock_guard

#include <xtd.core/include/xtd/lock.h>

Provides a mechanism that synchronizes access to objects with xtd::threading::monitor.

using lock = xtd::threading::lock_guard

Namespace

xtd

Library

xtd.core

Examples

The following example uses the xtd::lock class to synchronize access to a single instance of a random number generator represented by the xtd::random class. The example creates ten threads, each of which executes asynchronously on a thread pool thread. Each thread generates 10,000 random numbers, calculates their average, and updates two procedure-level variables that maintain a running total of the number of random numbers generated and their sum. After all threads have executed, these two values are then used to calculate the overall mean.

#include <xtd/threading/thread_pool>
#include <xtd/console>
#include <xtd/lock>
#include <xtd/random>
#include <xtd/startup>
 
using namespace xtd;
using namespace xtd::threading;
 
namespace examples {
  class account : public object {
  public:
    explicit account(int initial) : balance(initial) {}
    
    void do_transactions() {
      for (auto i = 0; i < 100; ++i)
        withdraw(random.next(1, 100));
    }
    
  private:
    int withdraw(int amount) {
      // This condition never is true unless the lock statement is commented out.
      if (balance < 0) throw system_exception {"Negative Balance", csf_};
      
      // Comment out the next line to see the effect of leaving out the lock keyword.
      lock_(balance) {
        if (balance < amount) return 0;
        console::write_line("Balance before Withdrawal :  {0}", balance);
        console::write_line("Amount to Withdraw        : -{0}", amount);
        balance = balance - amount;
        console::write_line("Balance after Withdrawal  :  {0}", balance);
        return amount;
      }
      return 0;
    }
 
    int balance = 0;
    xtd::random random;
  };
  
  class program {
  public:
    static void main() {
      auto account = examples::account {1000};
      
      for (auto i = 0; i < 10; ++i)
        thread_pool::queue_user_work_item({account, &account::do_transactions});
      
      thread_pool::close();
    }
  };
}
 
startup_(examples::program::main);
 
// This code can produce the following output:
//
// Balance before Withdrawal :  1000
// Amount to Withdraw        : -75
// Balance after Withdrawal  :  925
// Balance before Withdrawal :  925
// Amount to Withdraw        : -84
// Balance after Withdrawal  :  841
// Balance before Withdrawal :  841
// Amount to Withdraw        : -69
// Balance after Withdrawal  :  772
// Balance before Withdrawal :  772
// Amount to Withdraw        : -71
// Balance after Withdrawal  :  701
// Balance before Withdrawal :  701
// Amount to Withdraw        : -84
// Balance after Withdrawal  :  617
// Balance before Withdrawal :  617
// Amount to Withdraw        : -81
// Balance after Withdrawal  :  536
// Balance before Withdrawal :  536
// Amount to Withdraw        : -15
// Balance after Withdrawal  :  521
// Balance before Withdrawal :  521
// Amount to Withdraw        : -93
// Balance after Withdrawal  :  428
// Balance before Withdrawal :  428
// Amount to Withdraw        : -6
// Balance after Withdrawal  :  422
// Balance before Withdrawal :  422
// Amount to Withdraw        : -54
// Balance after Withdrawal  :  368
// Balance before Withdrawal :  368
// Amount to Withdraw        : -52
// Balance after Withdrawal  :  316
// Balance before Withdrawal :  316
// Amount to Withdraw        : -67
// Balance after Withdrawal  :  249
// Balance before Withdrawal :  249
// Amount to Withdraw        : -93
// Balance after Withdrawal  :  156
// Balance before Withdrawal :  156
// Amount to Withdraw        : -60
// Balance after Withdrawal  :  96
// Balance before Withdrawal :  96
// Amount to Withdraw        : -7
// Balance after Withdrawal  :  89
// Balance before Withdrawal :  89
// Amount to Withdraw        : -42
// Balance after Withdrawal  :  47
// Balance before Withdrawal :  47
// Amount to Withdraw        : -1
// Balance after Withdrawal  :  46
// Balance before Withdrawal :  46
// Amount to Withdraw        : -22
// Balance after Withdrawal  :  24
// Balance before Withdrawal :  24
// Amount to Withdraw        : -18
// Balance after Withdrawal  :  6
// Balance before Withdrawal :  6
// Amount to Withdraw        : -2
// Balance after Withdrawal  :  4
// Balance before Withdrawal :  4
// Amount to Withdraw        : -2
// Balance after Withdrawal  :  2
// Balance before Withdrawal :  2
// Amount to Withdraw        : -2
// Balance after Withdrawal  :  0

Remarks

See xtd::threading::monitor for more information.

Enumeration Type Documentation

event_reset_mode

enum class xtd::threading::event_reset_mode

strong

#include <xtd.core/include/xtd/threading/event_reset_mode.h>

Indicates whether an xtd::threading::event_wait_handle is reset automatically or manually after receiving a signal.

enum class event_reset_mode

Header

#include <xtd/threading/event_reset_mode> 

Namespace

xtd::threading

Library

xtd.core

Enumerator
auto_reset	When signaled, the xtd::threading::event_wait_handle resets automatically after releasing a single thread. If no threads are waiting, the xtd::threading::event_wait_handle remains signaled until a thread blocks, and resets after releasing the thread.
manual_reset	When signaled, the xtd::threading::event_wait_handle releases all waiting threads and remains signaled until it is manually reset.

thread_priority

enum class xtd::threading::thread_priority

strong

#include <xtd.core/include/xtd/threading/thread_priority.h>

Specifies the scheduling priority of a system::threading::thread.

enum class thread_priority

Header

#include <xtd/threading/thread_priority> 

Namespace

xtd::threading

Library

xtd.core

Enumerator
lowest	The system::threading::thread can be scheduled after threads with any other priority.
below_normal	The system::threading::thread can be scheduled after threads with thread_priority::normal priority and before those with thread_priority::lowest priority.
normal	The system::threading::thread can be scheduled after threads with thread_priority::above_normal priority and before those with thread_priority::below_normal priority. Threads have thread_priority::normal priority by default.
above_normal	The system::threading::thread can be scheduled after threads with thread_priority::highest priority and before those with thread_priority::normal priority.
highest	The system::threading::thread can be scheduled before threads with any other priority.

thread_state

enum class xtd::threading::thread_state

strong

#include <xtd.core/include/xtd/threading/thread_state.h>

Specifies the execution states of a System::Threading::Thread.

enum class thread_state

Header

#include <xtd/threading/thread_state> 

Namespace

xtd::threading

Library

xtd.core

Enumerator
running	The thread_state has been started, it is not blocked, and there is no pending System::Threading::ThreadAbortException.
stop_requested	The thread_state is being requested to stop. This is for internal use only.
suspend_requested	The thread_state is being requested to suspend.
background	The thread_state is being executed as a background thread_state, as opposed to a foreground thread_state. This state is controlled by setting the System::Threading::Thread.Isbackground property.
unstarted	The System::Threading::Thread.Start() method has not been invoked on the thread_state.
stopped	The thread_state has stopped.
wait_sleep_join	The thread_state is blocked. This could be the result of calling System::Threading::Thread.Sleep(System::Int32) or System::Threading::Thread.Join(), of requesting a lock � for example, by calling System::Threading::Monitor.Enter(System::object) or System::Threading::Monitor.Wait(System::object,System::Int32,System::Boolean) or of waiting on a thread_state synchronization object such as System::Threading::ManualResetEvent.
suspended	The thread_state has been suspended.
abort_requested	The System::Threading::Thread.Abort(System::object) method has been invoked on the thread_state, but the thread_state has not yet received the pending System::Threading::ThreadAbortException that will attempt to terminate it.
aborted	The thread_state state includes System::Threading::ThreadState.abort_requested and the thread_state is now dead, but its state has not yet changed to System::Threading::ThreadState.stopped.