Provides waitable timer functionality. More...

#include <basic_waitable_timer.hpp>

Classes
struct	rebind_executor
	Rebinds the timer type to another executor. More...

Public Types
typedef Executor	executor_type
	The type of the executor associated with the object.

typedef Clock	clock_type
	The clock type.

typedef clock_type::duration	duration
	The duration type of the clock.

typedef clock_type::time_point	time_point
	The time point type of the clock.

typedef WaitTraits	traits_type
	The wait traits type.

Public Member Functions
	basic_waitable_timer (const executor_type &ex)
	Constructor. More...

template<typename ExecutionContext >
	basic_waitable_timer (ExecutionContext &context, typename enable_if< is_convertible< ExecutionContext &, execution_context &>::value >::type *=0)
	Constructor. More...

	basic_waitable_timer (const executor_type &ex, const time_point &expiry_time)
	Constructor to set a particular expiry time as an absolute time. More...

template<typename ExecutionContext >
	basic_waitable_timer (ExecutionContext &context, const time_point &expiry_time, typename enable_if< is_convertible< ExecutionContext &, execution_context &>::value >::type *=0)
	Constructor to set a particular expiry time as an absolute time. More...

	basic_waitable_timer (const executor_type &ex, const duration &expiry_time)
	Constructor to set a particular expiry time relative to now. More...

template<typename ExecutionContext >
	basic_waitable_timer (ExecutionContext &context, const duration &expiry_time, typename enable_if< is_convertible< ExecutionContext &, execution_context &>::value >::type *=0)
	Constructor to set a particular expiry time relative to now. More...

	~basic_waitable_timer ()
	Destroys the timer. More...

executor_type	get_executor () ASIO_NOEXCEPT
	Get the executor associated with the object.

std::size_t	cancel ()
	Cancel any asynchronous operations that are waiting on the timer. More...

std::size_t	cancel (asio::error_code &ec)
	(Deprecated: Use non-error_code overload.) Cancel any asynchronous operations that are waiting on the timer. More...

std::size_t	cancel_one ()
	Cancels one asynchronous operation that is waiting on the timer. More...

std::size_t	cancel_one (asio::error_code &ec)
	(Deprecated: Use non-error_code overload.) Cancels one asynchronous operation that is waiting on the timer. More...

time_point	expires_at () const
	(Deprecated: Use expiry().) Get the timer's expiry time as an absolute time. More...

time_point	expiry () const
	Get the timer's expiry time as an absolute time. More...

std::size_t	expires_at (const time_point &expiry_time)
	Set the timer's expiry time as an absolute time. More...

std::size_t	expires_at (const time_point &expiry_time, asio::error_code &ec)
	(Deprecated: Use non-error_code overload.) Set the timer's expiry time as an absolute time. More...

std::size_t	expires_after (const duration &expiry_time)
	Set the timer's expiry time relative to now. More...

duration	expires_from_now () const
	(Deprecated: Use expiry().) Get the timer's expiry time relative to now. More...

std::size_t	expires_from_now (const duration &expiry_time)
	(Deprecated: Use expires_after().) Set the timer's expiry time relative to now. More...

std::size_t	expires_from_now (const duration &expiry_time, asio::error_code &ec)
	(Deprecated: Use expires_after().) Set the timer's expiry time relative to now. More...

void	wait ()
	Perform a blocking wait on the timer. More...

void	wait (asio::error_code &ec)
	Perform a blocking wait on the timer. More...

template<WaitHandler ASIO_DEFAULT_COMPLETION_TOKEN_TYPE>
	ASIO_INITFN_AUTO_RESULT_TYPE (WaitHandler, void(asio::error_code)) async_wait(ASIO_MOVE_ARG(WaitHandler) handler ASIO_DEFAULT_COMPLETION_TOKEN(executor_type))
	Start an asynchronous wait on the timer. More...

Detailed Description

template<typename Clock, typename WaitTraits, typename Executor>
class asio::basic_waitable_timer< Clock, WaitTraits, Executor >

Provides waitable timer functionality.

The basic_waitable_timer class template provides the ability to perform a blocking or asynchronous wait for a timer to expire.

A waitable timer is always in one of two states: "expired" or "not expired". If the wait() or async_wait() function is called on an expired timer, the wait operation will complete immediately.

Most applications will use one of the asio::steady_timer, asio::system_timer or asio::high_resolution_timer typedefs.

Note: This waitable timer functionality is for use with the C++11 standard library's <chrono> facility, or with the Boost.Chrono library.

Thread Safety: Distinct objects: Safe.
Shared objects: Unsafe.

Examples: Performing a blocking wait (C++11):
// Construct a timer without setting an expiry time.
asio::steady_timer timer(my_context);
// Set an expiry time relative to now.
timer.expires_after(std::chrono::seconds(5));
// Wait for the timer to expire.
timer.wait();

: Performing an asynchronous wait (C++11):
void handler(const asio::error_code& error)
{
if (!error)
{
// Timer expired.
}
}
...
// Construct a timer with an absolute expiry time.
asio::steady_timer timer(my_context,
std::chrono::steady_clock::now() + std::chrono::seconds(60));
// Start an asynchronous wait.
timer.async_wait(handler);

Changing an active waitable timer's expiry time

Changing the expiry time of a timer while there are pending asynchronous waits causes those wait operations to be cancelled. To ensure that the action associated with the timer is performed only once, use something like this: used:

void on_some_event()
{
  if (my_timer.expires_after(seconds(5)) > 0)
  {
    // We managed to cancel the timer. Start new asynchronous wait.
    my_timer.async_wait(on_timeout);
  }
  else
  {
    // Too late, timer has already expired!
  }
}
void on_timeout(const asio::error_code& e)
{
  if (e != asio::error::operation_aborted)
  {
    // Timer was not cancelled, take necessary action.
  }
}

The asio::basic_waitable_timer::expires_after() function cancels any pending asynchronous waits, and returns the number of asynchronous waits that were cancelled. If it returns 0 then you were too late and the wait handler has already been executed, or will soon be executed. If it returns 1 then the wait handler was successfully cancelled.

If a wait handler is cancelled, the asio::error_code passed to it contains the value asio::error::operation_aborted.

Constructor & Destructor Documentation

◆ basic_waitable_timer() [1/6]

template<typename Clock , typename WaitTraits , typename Executor >

asio::basic_waitable_timer< Clock, WaitTraits, Executor >::basic_waitable_timer ( const executor_type & ex )

inlineexplicit

Constructor.

This constructor creates a timer without setting an expiry time. The expires_at() or expires_after() functions must be called to set an expiry time before the timer can be waited on.

Parameters

ex	The I/O executor that the timer will use, by default, to dispatch handlers for any asynchronous operations performed on the timer.

◆ basic_waitable_timer() [2/6]

template<typename Clock , typename WaitTraits , typename Executor >

template<typename ExecutionContext >

asio::basic_waitable_timer< Clock, WaitTraits, Executor >::basic_waitable_timer	(	ExecutionContext &	context,
		typename enable_if< is_convertible< ExecutionContext &, execution_context &>::value >::type *	= `0`
	)

inlineexplicit

Constructor.

This constructor creates a timer without setting an expiry time. The expires_at() or expires_after() functions must be called to set an expiry time before the timer can be waited on.

Parameters

context An execution context which provides the I/O executor that the timer will use, by default, to dispatch handlers for any asynchronous operations performed on the timer.

◆ basic_waitable_timer() [3/6]

template<typename Clock , typename WaitTraits , typename Executor >

asio::basic_waitable_timer< Clock, WaitTraits, Executor >::basic_waitable_timer	(	const executor_type &	ex,
		const time_point &	expiry_time
	)

inline

Constructor to set a particular expiry time as an absolute time.

This constructor creates a timer and sets the expiry time.

Parameters

ex	The I/O executor object that the timer will use, by default, to dispatch handlers for any asynchronous operations performed on the timer.
expiry_time	The expiry time to be used for the timer, expressed as an absolute time.

◆ basic_waitable_timer() [4/6]

template<typename Clock , typename WaitTraits , typename Executor >

template<typename ExecutionContext >

asio::basic_waitable_timer< Clock, WaitTraits, Executor >::basic_waitable_timer	(	ExecutionContext &	context,
		const time_point &	expiry_time,
		typename enable_if< is_convertible< ExecutionContext &, execution_context &>::value >::type *	= `0`
	)

inlineexplicit

Constructor to set a particular expiry time as an absolute time.

This constructor creates a timer and sets the expiry time.

Parameters

context	An execution context which provides the I/O executor that the timer will use, by default, to dispatch handlers for any asynchronous operations performed on the timer.
expiry_time	The expiry time to be used for the timer, expressed as an absolute time.

◆ basic_waitable_timer() [5/6]

template<typename Clock , typename WaitTraits , typename Executor >

asio::basic_waitable_timer< Clock, WaitTraits, Executor >::basic_waitable_timer	(	const executor_type &	ex,
		const duration &	expiry_time
	)

inline

Constructor to set a particular expiry time relative to now.

This constructor creates a timer and sets the expiry time.

Parameters

ex	The I/O executor that the timer will use, by default, to dispatch handlers for any asynchronous operations performed on the timer.
expiry_time	The expiry time to be used for the timer, relative to now.

◆ basic_waitable_timer() [6/6]

template<typename Clock , typename WaitTraits , typename Executor >

template<typename ExecutionContext >

asio::basic_waitable_timer< Clock, WaitTraits, Executor >::basic_waitable_timer	(	ExecutionContext &	context,
		const duration &	expiry_time,
		typename enable_if< is_convertible< ExecutionContext &, execution_context &>::value >::type *	= `0`
	)

inlineexplicit

Constructor to set a particular expiry time relative to now.

This constructor creates a timer and sets the expiry time.

Parameters

context	An execution context which provides the I/O executor that the timer will use, by default, to dispatch handlers for any asynchronous operations performed on the timer.
expiry_time	The expiry time to be used for the timer, relative to now.

◆ ~basic_waitable_timer()

template<typename Clock , typename WaitTraits , typename Executor >

asio::basic_waitable_timer< Clock, WaitTraits, Executor >::~basic_waitable_timer ( )

inline

Destroys the timer.

This function destroys the timer, cancelling any outstanding asynchronous wait operations associated with the timer as if by calling cancel.

Member Function Documentation

◆ ASIO_INITFN_AUTO_RESULT_TYPE()

template<typename Clock , typename WaitTraits , typename Executor >

template<WaitHandler ASIO_DEFAULT_COMPLETION_TOKEN_TYPE>

asio::basic_waitable_timer< Clock, WaitTraits, Executor >::ASIO_INITFN_AUTO_RESULT_TYPE	(	WaitHandler	,
		void(asio::error_code)
	)

inline

Start an asynchronous wait on the timer.

This function may be used to initiate an asynchronous wait against the timer. It always returns immediately.

For each call to async_wait(), the supplied handler will be called exactly once. The handler will be called when:

The timer has expired.

The timer was cancelled, in which case the handler is passed the error code asio::error::operation_aborted.

Parameters

handler

The handler to be called when the timer expires. Copies will be made of the handler as required. The function signature of the handler must be:

 void handler(
  const asio::error_code& error // Result of operation.
); 

Regardless of whether the asynchronous operation completes immediately or not, the handler will not be invoked from within this function. On immediate completion, invocation of the handler will be performed in a manner equivalent to using asio::post().

◆ cancel() [1/2]

template<typename Clock , typename WaitTraits , typename Executor >

std::size_t asio::basic_waitable_timer< Clock, WaitTraits, Executor >::cancel ( )

inline

Cancel any asynchronous operations that are waiting on the timer.

This function forces the completion of any pending asynchronous wait operations against the timer. The handler for each cancelled operation will be invoked with the asio::error::operation_aborted error code.

Cancelling the timer does not change the expiry time.

Returns: The number of asynchronous operations that were cancelled.

Exceptions

asio::system_error Thrown on failure.

Note: If the timer has already expired when cancel() is called, then the handlers for asynchronous wait operations will:

have already been invoked; or

have been queued for invocation in the near future.

These handlers can no longer be cancelled, and therefore are passed an error code that indicates the successful completion of the wait operation.

◆ cancel() [2/2]

template<typename Clock , typename WaitTraits , typename Executor >

std::size_t asio::basic_waitable_timer< Clock, WaitTraits, Executor >::cancel ( asio::error_code & ec )

inline

(Deprecated: Use non-error_code overload.) Cancel any asynchronous operations that are waiting on the timer.

This function forces the completion of any pending asynchronous wait operations against the timer. The handler for each cancelled operation will be invoked with the asio::error::operation_aborted error code.

Cancelling the timer does not change the expiry time.

Parameters

ec	Set to indicate what error occurred, if any.

Returns: The number of asynchronous operations that were cancelled.

Note: If the timer has already expired when cancel() is called, then the handlers for asynchronous wait operations will:

have already been invoked; or

have been queued for invocation in the near future.

These handlers can no longer be cancelled, and therefore are passed an error code that indicates the successful completion of the wait operation.

◆ cancel_one() [1/2]

template<typename Clock , typename WaitTraits , typename Executor >

std::size_t asio::basic_waitable_timer< Clock, WaitTraits, Executor >::cancel_one ( )

inline

Cancels one asynchronous operation that is waiting on the timer.

This function forces the completion of one pending asynchronous wait operation against the timer. Handlers are cancelled in FIFO order. The handler for the cancelled operation will be invoked with the asio::error::operation_aborted error code.

Cancelling the timer does not change the expiry time.

Returns: The number of asynchronous operations that were cancelled. That is, either 0 or 1.

Exceptions

asio::system_error Thrown on failure.

Note: If the timer has already expired when cancel_one() is called, then the handlers for asynchronous wait operations will:

have already been invoked; or

have been queued for invocation in the near future.

These handlers can no longer be cancelled, and therefore are passed an error code that indicates the successful completion of the wait operation.

◆ cancel_one() [2/2]

template<typename Clock , typename WaitTraits , typename Executor >

std::size_t asio::basic_waitable_timer< Clock, WaitTraits, Executor >::cancel_one ( asio::error_code & ec )

inline

(Deprecated: Use non-error_code overload.) Cancels one asynchronous operation that is waiting on the timer.

This function forces the completion of one pending asynchronous wait operation against the timer. Handlers are cancelled in FIFO order. The handler for the cancelled operation will be invoked with the asio::error::operation_aborted error code.

Cancelling the timer does not change the expiry time.

Parameters

ec	Set to indicate what error occurred, if any.

Returns: The number of asynchronous operations that were cancelled. That is, either 0 or 1.

Note: If the timer has already expired when cancel_one() is called, then the handlers for asynchronous wait operations will:

have already been invoked; or

have been queued for invocation in the near future.

These handlers can no longer be cancelled, and therefore are passed an error code that indicates the successful completion of the wait operation.

◆ expires_after()

template<typename Clock , typename WaitTraits , typename Executor >

std::size_t asio::basic_waitable_timer< Clock, WaitTraits, Executor >::expires_after ( const duration & expiry_time )

inline

Set the timer's expiry time relative to now.

This function sets the expiry time. Any pending asynchronous wait operations will be cancelled. The handler for each cancelled operation will be invoked with the asio::error::operation_aborted error code.

Parameters

expiry_time The expiry time to be used for the timer.

Returns: The number of asynchronous operations that were cancelled.

Exceptions

asio::system_error Thrown on failure.

Note: If the timer has already expired when expires_after() is called, then the handlers for asynchronous wait operations will:

have already been invoked; or

have been queued for invocation in the near future.

These handlers can no longer be cancelled, and therefore are passed an error code that indicates the successful completion of the wait operation.

◆ expires_at() [1/3]

template<typename Clock , typename WaitTraits , typename Executor >

time_point asio::basic_waitable_timer< Clock, WaitTraits, Executor >::expires_at ( ) const

inline

(Deprecated: Use expiry().) Get the timer's expiry time as an absolute time.

This function may be used to obtain the timer's current expiry time. Whether the timer has expired or not does not affect this value.

◆ expires_at() [2/3]

template<typename Clock , typename WaitTraits , typename Executor >

std::size_t asio::basic_waitable_timer< Clock, WaitTraits, Executor >::expires_at ( const time_point & expiry_time )

inline

Set the timer's expiry time as an absolute time.

This function sets the expiry time. Any pending asynchronous wait operations will be cancelled. The handler for each cancelled operation will be invoked with the asio::error::operation_aborted error code.

Parameters

expiry_time The expiry time to be used for the timer.

Returns: The number of asynchronous operations that were cancelled.

Exceptions

asio::system_error Thrown on failure.

Note: If the timer has already expired when expires_at() is called, then the handlers for asynchronous wait operations will:

have already been invoked; or

have been queued for invocation in the near future.

These handlers can no longer be cancelled, and therefore are passed an error code that indicates the successful completion of the wait operation.

◆ expires_at() [3/3]

template<typename Clock , typename WaitTraits , typename Executor >

std::size_t asio::basic_waitable_timer< Clock, WaitTraits, Executor >::expires_at	(	const time_point &	expiry_time,
		asio::error_code &	ec
	)

inline

(Deprecated: Use non-error_code overload.) Set the timer's expiry time as an absolute time.

This function sets the expiry time. Any pending asynchronous wait operations will be cancelled. The handler for each cancelled operation will be invoked with the asio::error::operation_aborted error code.

Parameters

expiry_time	The expiry time to be used for the timer.
ec	Set to indicate what error occurred, if any.

Returns: The number of asynchronous operations that were cancelled.

Note: If the timer has already expired when expires_at() is called, then the handlers for asynchronous wait operations will:

have already been invoked; or

have been queued for invocation in the near future.

These handlers can no longer be cancelled, and therefore are passed an error code that indicates the successful completion of the wait operation.

◆ expires_from_now() [1/3]

template<typename Clock , typename WaitTraits , typename Executor >

duration asio::basic_waitable_timer< Clock, WaitTraits, Executor >::expires_from_now ( ) const

inline

(Deprecated: Use expiry().) Get the timer's expiry time relative to now.

This function may be used to obtain the timer's current expiry time. Whether the timer has expired or not does not affect this value.

◆ expires_from_now() [2/3]

template<typename Clock , typename WaitTraits , typename Executor >

std::size_t asio::basic_waitable_timer< Clock, WaitTraits, Executor >::expires_from_now ( const duration & expiry_time )

inline

(Deprecated: Use expires_after().) Set the timer's expiry time relative to now.

This function sets the expiry time. Any pending asynchronous wait operations will be cancelled. The handler for each cancelled operation will be invoked with the asio::error::operation_aborted error code.

Parameters

expiry_time The expiry time to be used for the timer.

Returns: The number of asynchronous operations that were cancelled.

Exceptions

asio::system_error Thrown on failure.

Note: If the timer has already expired when expires_from_now() is called, then the handlers for asynchronous wait operations will:

have already been invoked; or

have been queued for invocation in the near future.

These handlers can no longer be cancelled, and therefore are passed an error code that indicates the successful completion of the wait operation.

◆ expires_from_now() [3/3]

template<typename Clock , typename WaitTraits , typename Executor >

std::size_t asio::basic_waitable_timer< Clock, WaitTraits, Executor >::expires_from_now	(	const duration &	expiry_time,
		asio::error_code &	ec
	)

inline

(Deprecated: Use expires_after().) Set the timer's expiry time relative to now.

This function sets the expiry time. Any pending asynchronous wait operations will be cancelled. The handler for each cancelled operation will be invoked with the asio::error::operation_aborted error code.

Parameters

expiry_time	The expiry time to be used for the timer.
ec	Set to indicate what error occurred, if any.

Returns: The number of asynchronous operations that were cancelled.

Note: If the timer has already expired when expires_from_now() is called, then the handlers for asynchronous wait operations will:

have already been invoked; or

have been queued for invocation in the near future.

These handlers can no longer be cancelled, and therefore are passed an error code that indicates the successful completion of the wait operation.

◆ expiry()

template<typename Clock , typename WaitTraits , typename Executor >

time_point asio::basic_waitable_timer< Clock, WaitTraits, Executor >::expiry ( ) const

inline

Get the timer's expiry time as an absolute time.

This function may be used to obtain the timer's current expiry time. Whether the timer has expired or not does not affect this value.

◆ wait() [1/2]

template<typename Clock , typename WaitTraits , typename Executor >

void asio::basic_waitable_timer< Clock, WaitTraits, Executor >::wait ( )

inline

Perform a blocking wait on the timer.

This function is used to wait for the timer to expire. This function blocks and does not return until the timer has expired.

Exceptions

asio::system_error Thrown on failure.

◆ wait() [2/2]

template<typename Clock , typename WaitTraits , typename Executor >

void asio::basic_waitable_timer< Clock, WaitTraits, Executor >::wait ( asio::error_code & ec )

inline

Perform a blocking wait on the timer.

This function is used to wait for the timer to expire. This function blocks and does not return until the timer has expired.

Parameters

ec	Set to indicate what error occurred, if any.

The documentation for this class was generated from the following file:

Thirdparty/asio/include/asio/basic_waitable_timer.hpp

Classes

Public Types

Public Member Functions

Detailed Description

template<typename Clock, typename WaitTraits, typename Executor> class asio::basic_waitable_timer< Clock, WaitTraits, Executor >

Constructor & Destructor Documentation

◆ basic_waitable_timer() [1/6]

◆ basic_waitable_timer() [2/6]

◆ basic_waitable_timer() [3/6]

◆ basic_waitable_timer() [4/6]

◆ basic_waitable_timer() [5/6]

◆ basic_waitable_timer() [6/6]

◆ ~basic_waitable_timer()

Member Function Documentation

◆ ASIO_INITFN_AUTO_RESULT_TYPE()

◆ cancel() [1/2]

◆ cancel() [2/2]

◆ cancel_one() [1/2]

◆ cancel_one() [2/2]

◆ expires_after()

◆ expires_at() [1/3]

◆ expires_at() [2/3]

◆ expires_at() [3/3]

◆ expires_from_now() [1/3]

◆ expires_from_now() [2/3]

◆ expires_from_now() [3/3]

◆ expiry()

◆ wait() [1/2]

◆ wait() [2/2]

template<typename Clock, typename WaitTraits, typename Executor>
class asio::basic_waitable_timer< Clock, WaitTraits, Executor >