concurrent_priority_queue Class
The concurrent_priority_queue class is a container that allows multiple threads to concurrently push and pop items. Items are popped in priority order where priority is determined by a functor supplied as a template argument.
Syntax
template <typename T,
typename _Compare= std::less<T>,
typename _Ax = std::allocator<T>
>,
typename _Ax = std::allocator<T>> class concurrent_priority_queue;
Parameters
T
The data type of the elements to be stored in the priority queue.
_Compare
The type of the function object that can compare two element values as sort keys to determine their relative order in the priority queue. This argument is optional and the binary predicate less<T> is the default value.
_Ax
The type that represents the stored allocator object that encapsulates details about the allocation and deallocation of memory for the concurrent priority queue. This argument is optional and the default value is allocator<T>.
Members
Public Typedefs
| Name | Description |
|---|---|
allocator_type |
A type that represents the allocator class for the concurrent priority queue. |
const_reference |
A type that represents a const reference to an element of the type stored in a concurrent priority queue. |
reference |
A type that represents a reference to an element of the type stored in a concurrent priority queue. |
size_type |
A type that counts the number of elements in a concurrent priority queue. |
value_type |
A type that represents the data type stored in a concurrent priority queue. |
Public Constructors
| Name | Description |
|---|---|
| concurrent_priority_queue | Overloaded. Constructs a concurrent priority queue. |
Public Methods
| Name | Description |
|---|---|
| clear | Erases all elements in the concurrent priority. This method is not concurrency-safe. |
| empty | Tests if the concurrent priority queue is empty at the time this method is called. This method is concurrency-safe. |
| get_allocator | Returns a copy of the allocator used to construct the concurrent priority queue. This method is concurrency-safe. |
| push | Overloaded. Adds an element to the concurrent priority queue. This method is concurrency-safe. |
| size | Returns the number of elements in the concurrent priority queue. This method is concurrency-safe. |
| swap | Swaps the contents of two concurrent priority queues. This method is not concurrency-safe. |
| try_pop | Removes and returns the highest priority element from the queue if the queue is non-empty. This method is concurrency-safe. |
Public Operators
| Name | Description |
|---|---|
| operator= | Overloaded. Assigns the contents of another concurrent_priority_queue object to this one. This method is not concurrency-safe. |
Remarks
For detailed information on the concurrent_priority_queue class, see Parallel Containers and Objects.
Inheritance Hierarchy
concurrent_priority_queue
Requirements
Header: concurrent_priority_queue.h
Namespace: concurrency
clear
Erases all elements in the concurrent priority. This method is not concurrency-safe.
void clear();
Remarks
clear is not concurrency-safe. You must ensure that no other threads are invoking methods on the concurrent priority queue when you call this method. clear does not free memory.
concurrent_priority_queue
Constructs a concurrent priority queue.
explicit concurrent_priority_queue(
const allocator_type& _Al = allocator_type());
explicit concurrent_priority_queue(
size_type _Init_capacity,
const allocator_type& _Al = allocator_type());
template<typename _InputIterator>
concurrent_priority_queue(_InputIterator _Begin,
_InputIterator _End,
const allocator_type& _Al = allocator_type());
concurrent_priority_queue(
const concurrent_priority_queue& _Src);
concurrent_priority_queue(
const concurrent_priority_queue& _Src,
const allocator_type& _Al);
concurrent_priority_queue(
concurrent_priority_queue&& _Src);
concurrent_priority_queue(
concurrent_priority_queue&& _Src,
const allocator_type& _Al);
Parameters
_InputIterator
The type of the input iterator.
_Al
The allocator class to use with this object.
_Init_capacity
The initial capacity of the concurrent_priority_queue object.
_Begin
The position of the first element in the range of elements to be copied.
_End
The position of the first element beyond the range of elements to be copied.
_Src
The source concurrent_priority_queue object to copy or move elements from.
Remarks
All constructors store an allocator object _Al and initialize the priority queue.
The first constructor specifies an empty initial priority queue and optionally specifies an allocator.
The second constructor specifies a priority queue with an initial capacity _Init_capacity and optionally specifies an allocator.
The third constructor specifies values supplied by the iterator range [ _Begin, _End) and optionally specifies an allocator.
The fourth and fifth constructors specify a copy of the priority queue _Src.
The sixth and seventh constructors specify a move of the priority queue _Src.
empty
Tests if the concurrent priority queue is empty at the time this method is called. This method is concurrency-safe.
bool empty() const;
Return Value
true if the priority queue was empty at the moment the function was called, false otherwise.
get_allocator
Returns a copy of the allocator used to construct the concurrent priority queue. This method is concurrency-safe.
allocator_type get_allocator() const;
Return Value
A copy of the allocator used to construct the concurrent_priority_queue object.
operator=
Assigns the contents of another concurrent_priority_queue object to this one. This method is not concurrency-safe.
concurrent_priority_queue& operator= (const concurrent_priority_queue& _Src);
concurrent_priority_queue& operator= (concurrent_priority_queue&& _Src);
Parameters
_Src
The source concurrent_priority_queue object.
Return Value
A reference to this concurrent_priority_queue object.
push
Adds an element to the concurrent priority queue. This method is concurrency-safe.
void push(const value_type& _Elem);
void push(value_type&& _Elem);
Parameters
_Elem
The element to be added to the concurrent priority queue.
size
Returns the number of elements in the concurrent priority queue. This method is concurrency-safe.
size_type size() const;
Return Value
The number of elements in this concurrent_priority_queue object.
Remarks
The returned size is guaranteed to include all elements added by calls to the function push. However, it may not reflect results of pending concurrent operations.
swap
Swaps the contents of two concurrent priority queues. This method is not concurrency-safe.
void swap(concurrent_priority_queue& _Queue);
Parameters
_Queue
The concurrent_priority_queue object to swap contents with.
try_pop
Removes and returns the highest priority element from the queue if the queue is non-empty. This method is concurrency-safe.
bool try_pop(reference _Elem);
Parameters
_Elem
A reference to a variable that will be populated with the highest priority element, if the queue is non-empty.
Return Value
true if a value was popped, false otherwise.