arene::base::latch Class Reference

Backport of std::latch from C++20. Provides a count-down latch that stays permanently signalled when the count reaches zero. For a given instance, every call to count_down or arrive_and_wait synchronizes-with every call to wait or arrive_and_wait, and every call to try_wait that returns true. More...

Public Member Functions
	latch (latch &&)=delete
	Not movable.
	latch (latch const &)=delete
	Not copyable.
constexpr	latch (std::ptrdiff_t initial_count)
	Construct a latch with the specified count. If the count is zero, then the latch will be already signalled.
	~latch ()=default
	Default destructor.
void	arrive_and_wait ()
	Count down the latch by 1 and blocks the current thread waiting for the latch to be signalled.
void	arrive_and_wait (std::ptrdiff_t const update)
	Count down the latch by update and blocks the current thread waiting for the latch to be signalled.
void	count_down ()
	Count down the latch by 1. If the counter reaches zero, the latch is permanently signalled, and any threads blocked in wait are unblocked.
void	count_down (std::ptrdiff_t update)
	Count down the latch by update. If the counter reaches zero, the latch is permanently signalled, and any threads blocked in wait are unblocked.
auto	operator= (latch &&) -> latch &=delete
	Not movable.
auto	operator= (latch const &) -> latch &=delete
	Not copyable.
auto	try_wait () const noexcept -> bool
	Check if the latch is signalled without blocking.
void	wait () const
	Blocks the current thread until the latch becomes signalled.

Static Public Member Functions
static constexpr auto	max () noexcept -> std::ptrdiff_t
	Get the maximum supported count.

Detailed Description

Backport of std::latch from C++20. Provides a count-down latch that stays permanently signalled when the count reaches zero. For a given instance, every call to count_down or arrive_and_wait synchronizes-with every call to wait or arrive_and_wait, and every call to try_wait that returns true.

Constructor & Destructor Documentation

latch() [1/3]

arene::base::latch::latch ( std::ptrdiff_t initial_count )

inlineexplicitconstexpr

Construct a latch with the specified count. If the count is zero, then the latch will be already signalled.

Parameters

initial_count

The initial count for the latch

Precondition

initial_count >= 0

~latch()

arene::base::latch::~latch ( )

default

Default destructor.

latch() [2/3]

arene::base::latch::latch ( latch const & )

delete

Not copyable.

latch() [3/3]

arene::base::latch::latch ( latch && )

delete

Not movable.

Member Function Documentation

arrive_and_wait() [1/2]

void arene::base::latch::arrive_and_wait ( )

inline

Count down the latch by 1 and blocks the current thread waiting for the latch to be signalled.

Exceptions

std::system_error

on error

arrive_and_wait() [2/2]

void arene::base::latch::arrive_and_wait ( std::ptrdiff_t const update )

inline

Count down the latch by update and blocks the current thread waiting for the latch to be signalled.

Parameters

update

The amount by which to decrease the count

Exceptions

std::system_error

on error

count_down() [1/2]

void arene::base::latch::count_down ( )

inline

Count down the latch by 1. If the counter reaches zero, the latch is permanently signalled, and any threads blocked in wait are unblocked.

Precondition

The latch must not be signalled.

Exceptions

std::system_error

on error

count_down() [2/2]

void arene::base::latch::count_down ( std::ptrdiff_t update )

inline

Count down the latch by update. If the counter reaches zero, the latch is permanently signalled, and any threads blocked in wait are unblocked.

Parameters

update

The amount by which to decrease the count

Precondition

(update >= 0) && (update <= count_)

Exceptions

std::system_error

on error

max()

static constexpr auto arene::base::latch::max ( ) -> std::ptrdiff_t

inlinestaticconstexprnoexcept

Get the maximum supported count.

Returns

The maximum count

operator=() [1/2]

auto arene::base::latch::operator= ( latch && ) -> latch &=delete

delete

Not movable.

operator=() [2/2]

auto arene::base::latch::operator= ( latch const & ) -> latch &=delete

delete

Not copyable.

try_wait()

auto arene::base::latch::try_wait ( ) const -> bool

inlinenoexcept

Check if the latch is signalled without blocking.

Returns

true if the latch is signalled, false otherwise.

wait()

void arene::base::latch::wait ( ) const

inline

Blocks the current thread until the latch becomes signalled.

Exceptions

std::system_error

on error

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

• arene/base/synchronization/latch.hpp