boost::lockfree::queue< T, A0, A1, A2 > Class Template Reference

The queue class provides a multi-writer/multi-reader queue, pushing and popping is lock-free, construction/destruction has to be synchronized. More...

#include <queue.hpp>

Public Types
typedef T	value_type
typedef implementation_defined::allocator	allocator
typedef implementation_defined::size_type	size_type

Public Member Functions
bool	is_lock_free (void) const
void	reserve (size_type n)
	Allocate n nodes for freelist. More...
void	reserve_unsafe (size_type n)
	Allocate n nodes for freelist. More...
	~queue (void)
	Destroys queue, free all nodes from freelist. More...
bool	empty (void) const
	Check if the queue is empty. More...
bool	push (T const &t)
	Pushes object t to the queue. More...
bool	bounded_push (T const &t)
	Pushes object t to the queue. More...
bool	unsynchronized_push (T const &t)
	Pushes object t to the queue. More...
bool	pop (T &ret)
	Pops object from queue. More...
template<typename U >
bool	pop (U &ret)
	Pops object from queue. More...
bool	unsynchronized_pop (T &ret)
	Pops object from queue. More...
template<typename U >
bool	unsynchronized_pop (U &ret)
	Pops object from queue. More...
template<typename Functor >
bool	consume_one (Functor &f)
	consumes one element via a functor More...
template<typename Functor >
bool	consume_one (Functor const &f)
	consumes one element via a functor More...
template<typename Functor >
size_t	consume_all (Functor &f)
	consumes all elements via a functor More...
template<typename Functor >
size_t	consume_all (Functor const &f)
	consumes all elements via a functor More...
	queue (void)
	Construct queue. More...
template<typename U >
	queue (typename node_allocator::template rebind< U >::other const &alloc)
	Construct queue. More...
	queue (allocator const &alloc)
	Construct queue. More...
	queue (size_type n)
	Construct queue, allocate n nodes for the freelist. More...
template<typename U >
	queue (size_type n, typename node_allocator::template rebind< U >::other const &alloc)
	Construct queue, allocate n nodes for the freelist. More...

Detailed Description

template<typename T, class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>
class boost::lockfree::queue< T, A0, A1, A2 >

The queue class provides a multi-writer/multi-reader queue, pushing and popping is lock-free, construction/destruction has to be synchronized.

It uses a freelist for memory management, freed nodes are pushed to the freelist and not returned to the OS before the queue is destroyed.

Policies:

• boost::lockfree::fixed_sized, defaults to boost::lockfree::fixed_sized<false>
  Can be used to completely disable dynamic memory allocations during push in order to ensure lockfree behavior.
  If the data structure is configured as fixed-sized, the internal nodes are stored inside an array and they are addressed by array indexing. This limits the possible size of the queue to the number of elements that can be addressed by the index type (usually 2**16-2), but on platforms that lack double-width compare-and-exchange instructions, this is the best way to achieve lock-freedom.
• boost::lockfree::capacity, optional
  If this template argument is passed to the options, the size of the queue is set at compile-time.
  It this option implies fixed_sized<true>
• boost::lockfree::allocator, defaults to boost::lockfree::allocator<std::allocator<void>>
  Specifies the allocator that is used for the internal freelist

Requirements:

• T must have a copy constructor
• T must have a trivial assignment operator
• T must have a trivial destructor

Member Typedef Documentation

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

typedef implementation_defined::allocator boost::lockfree::queue< T, A0, A1, A2 >::allocator

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

typedef implementation_defined::size_type boost::lockfree::queue< T, A0, A1, A2 >::size_type

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

typedef T boost::lockfree::queue< T, A0, A1, A2 >::value_type

Constructor & Destructor Documentation

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

boost::lockfree::queue< T, A0, A1, A2 >::queue ( void  )

inline

Construct queue.

References BOOST_ASSERT.

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

template<typename U >

boost::lockfree::queue< T, A0, A1, A2 >::queue ( typename node_allocator::template rebind< U >::other const &  alloc )

inlineexplicit

Construct queue.

References boost::BOOST_STATIC_ASSERT().

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

boost::lockfree::queue< T, A0, A1, A2 >::queue ( allocator const &  alloc )

inlineexplicit

Construct queue.

References BOOST_ASSERT.

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

boost::lockfree::queue< T, A0, A1, A2 >::queue ( size_type  n )

inlineexplicit

Construct queue, allocate n nodes for the freelist.

References BOOST_ASSERT.

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

template<typename U >

boost::lockfree::queue< T, A0, A1, A2 >::queue ( size_type  n, typename node_allocator::template rebind< U >::other const &  alloc  )

inline

Construct queue, allocate n nodes for the freelist.

References boost::BOOST_STATIC_ASSERT().

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

boost::lockfree::queue< T, A0, A1, A2 >::~queue ( void  )

inline

Destroys queue, free all nodes from freelist.

References boost::memory_order_relaxed, and boost::lockfree::queue< T, A0, A1, A2 >::unsynchronized_pop().

Member Function Documentation

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

bool boost::lockfree::queue< T, A0, A1, A2 >::bounded_push ( T const &  t )

inline

Pushes object t to the queue.

Postcondition

object will be pushed to the queue, if internal node can be allocated

Returns

true, if the push operation is successful.

Note

Thread-safe and non-blocking. If internal memory pool is exhausted, operation will fail

Exceptions

if	memory allocator throws

References boost::flyweights::t.

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

template<typename Functor >

size_t boost::lockfree::queue< T, A0, A1, A2 >::consume_all ( Functor &  f )

inline

consumes all elements via a functor

sequentially pops all elements from the queue and applies the functor on each object

Returns

number of elements that are consumed

Note

Thread-safe and non-blocking, if functor is thread-safe and non-blocking

References boost::lockfree::queue< T, A0, A1, A2 >::consume_one().

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

template<typename Functor >

size_t boost::lockfree::queue< T, A0, A1, A2 >::consume_all ( Functor const &  f )

inline

consumes all elements via a functor

sequentially pops all elements from the queue and applies the functor on each object

Returns

number of elements that are consumed

Note

Thread-safe and non-blocking, if functor is thread-safe and non-blocking

References boost::lockfree::queue< T, A0, A1, A2 >::consume_one().

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

template<typename Functor >

bool boost::lockfree::queue< T, A0, A1, A2 >::consume_one ( Functor &  f )

inline

consumes one element via a functor

pops one element from the queue and applies the functor on this object

Returns

true, if one element was consumed

Note

Thread-safe and non-blocking, if functor is thread-safe and non-blocking

References boost::lockfree::queue< T, A0, A1, A2 >::pop(), and boost::sinks::event_log::success.

Referenced by boost::lockfree::queue< T, A0, A1, A2 >::consume_all().

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

template<typename Functor >

bool boost::lockfree::queue< T, A0, A1, A2 >::consume_one ( Functor const &  f )

inline

consumes one element via a functor

pops one element from the queue and applies the functor on this object

Returns

true, if one element was consumed

Note

Thread-safe and non-blocking, if functor is thread-safe and non-blocking

References boost::lockfree::queue< T, A0, A1, A2 >::pop(), and boost::sinks::event_log::success.

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

bool boost::lockfree::queue< T, A0, A1, A2 >::empty ( void  ) const

inline

Check if the queue is empty.

Returns

true, if the queue is empty, false otherwise

Note

The result is only accurate, if no other thread modifies the queue. Therefore it is rarely practical to use this value in program logic.

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

bool boost::lockfree::queue< T, A0, A1, A2 >::is_lock_free ( void  ) const

inline

Returns

true, if implementation is lock-free.

Warning

It only checks, if the queue head and tail nodes and the freelist can be modified in a lock-free manner. On most platforms, the whole implementation is lock-free, if this is true. Using c++0x-style atomics, there is no possibility to provide a completely accurate implementation, because one would need to test every internal node, which is impossible if further nodes will be allocated from the operating system.

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

bool boost::lockfree::queue< T, A0, A1, A2 >::pop ( T &  ret )

inline

Pops object from queue.

Postcondition

if pop operation is successful, object will be copied to ret.

Returns

true, if the pop operation is successful, false if queue was empty.

Note

Thread-safe and non-blocking

Referenced by boost::lockfree::queue< T, A0, A1, A2 >::consume_one().

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

template<typename U >

bool boost::lockfree::queue< T, A0, A1, A2 >::pop ( U &  ret )

inline

Pops object from queue.

Precondition

type U must be constructible by T and copyable, or T must be convertible to U

Postcondition

if pop operation is successful, object will be copied to ret.

Returns

true, if the pop operation is successful, false if queue was empty.

Note

Thread-safe and non-blocking

References boost::memory_order_acquire.

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

bool boost::lockfree::queue< T, A0, A1, A2 >::push ( T const &  t )

inline

Pushes object t to the queue.

Postcondition

object will be pushed to the queue, if internal node can be allocated

Returns

true, if the push operation is successful.

Note

Thread-safe. If internal memory pool is exhausted and the memory pool is not fixed-sized, a new node will be allocated from the OS. This may not be lock-free.

References boost::flyweights::t.

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

void boost::lockfree::queue< T, A0, A1, A2 >::reserve ( size_type  n )

inline

Allocate n nodes for freelist.

Precondition

only valid if no capacity<> argument given

Note

thread-safe, may block if memory allocator blocks

References boost::n.

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

void boost::lockfree::queue< T, A0, A1, A2 >::reserve_unsafe ( size_type  n )

inline

Allocate n nodes for freelist.

Precondition

only valid if no capacity<> argument given

Note

not thread-safe, may block if memory allocator blocks

References boost::n.

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

bool boost::lockfree::queue< T, A0, A1, A2 >::unsynchronized_pop ( T &  ret )

inline

Pops object from queue.

Postcondition

if pop operation is successful, object will be copied to ret.

Returns

true, if the pop operation is successful, false if queue was empty.

Note

Not thread-safe, but non-blocking

Referenced by boost::lockfree::queue< T, A0, A1, A2 >::~queue().

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

template<typename U >

bool boost::lockfree::queue< T, A0, A1, A2 >::unsynchronized_pop ( U &  ret )

inline

Pops object from queue.

Precondition

type U must be constructible by T and copyable, or T must be convertible to U

Postcondition

if pop operation is successful, object will be copied to ret.

Returns

true, if the pop operation is successful, false if queue was empty.

Note

Not thread-safe, but non-blocking

References boost::memory_order_relaxed.

template<typename T , class A0 = boost::parameter::void_, class A1 = boost::parameter::void_, class A2 = boost::parameter::void_>

bool boost::lockfree::queue< T, A0, A1, A2 >::unsynchronized_push ( T const &  t )

inline

Pushes object t to the queue.

Postcondition

object will be pushed to the queue, if internal node can be allocated

Returns

true, if the push operation is successful.

Note

Not Thread-safe. If internal memory pool is exhausted and the memory pool is not fixed-sized, a new node will be allocated from the OS. This may not be lock-free.

Exceptions

if	memory allocator throws

References boost::memory_order_relaxed, and boost::flyweights::t.

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

• boost_1_57_0/boost/lockfree/queue.hpp