cds  2.2.0
cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits > Class Template Reference

Michael's ordered list (key-value pair), template specialization for RCU. More...

#include <cds/container/michael_kvlist_rcu.h>

Inheritance diagram for cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >:
cds::intrusive::MichaelList< cds::urcu::gc< RCU >, implementation_defined, Traits >

Public Types

typedef cds::urcu::gc< RCU > gc
 Garbage collector.
 
typedef Key key_type
 Key type.
 
typedef Value mapped_type
 Type of value stored in the list.
 
typedef std::pair< key_type const, mapped_typevalue_type
 key/value pair stored in the list
 
typedef Traits traits
 List traits.
 
typedef base_class::back_off back_off
 Back-off strategy.
 
typedef maker::allocator_type allocator_type
 Allocator type used for allocate/deallocate the nodes.
 
typedef base_class::item_counter item_counter
 Item counting policy.
 
typedef maker::key_comparator key_comparator
 key comparison functor
 
typedef base_class::memory_model memory_model
 Memory ordering. See michael_list::traits::memory_model.
 
typedef base_class::stat stat
 Internal statistics.
 
typedef base_class::rcu_check_deadlock rcu_check_deadlock
 RCU deadlock checking policy.
 
typedef gc::scoped_lock rcu_lock
 RCU scoped lock.
 
using exempt_ptr = cds::urcu::exempt_ptr< gc, node_type, value_type, typename maker::intrusive_traits::disposer, cds::urcu::details::conventional_exempt_pair_cast< node_type, value_type > >
 pointer to extracted node
 
typedef cds::urcu::raw_ptr_adaptor< value_type, typename base_class::raw_ptr, raw_ptr_converter > raw_ptr
 Result of get(), get_with() functions - pointer to the node found.
 

Public Member Functions

 MichaelKVList ()
 Default constructor. More...
 
 ~MichaelKVList ()
 List destructor. More...
 
template<typename K >
bool insert (const K &key)
 Inserts new node with key and default value. More...
 
template<typename K , typename V >
bool insert (const K &key, const V &val)
 Inserts new node with a key and a value. More...
 
template<typename K , typename Func >
bool insert_with (const K &key, Func func)
 Inserts new node and initialize it by a functor. More...
 
template<typename K , typename Func >
std::pair< bool, bool > update (const K &key, Func func, bool bAllowInsert=true)
 Updates an element with given key. More...
 
template<typename K , typename... Args>
bool emplace (K &&key, Args &&... args)
 Inserts data of type mapped_type constructed with std::forward<Args>(args)... More...
 
template<typename K >
bool erase (K const &key)
 Deletes key from the list. More...
 
template<typename K , typename Less >
bool erase_with (K const &key, Less pred)
 Deletes the item from the list using pred predicate for searching. More...
 
template<typename K , typename Func >
bool erase (K const &key, Func f)
 Deletes key from the list. More...
 
template<typename K , typename Less , typename Func >
bool erase_with (K const &key, Less pred, Func f)
 Deletes the item from the list using pred predicate for searching. More...
 
template<typename K >
exempt_ptr extract (K const &key)
 Extracts an item from the list. More...
 
template<typename K , typename Less >
exempt_ptr extract_with (K const &key, Less pred)
 Extracts an item from the list using pred predicate for searching. More...
 
template<typename Q >
bool contains (Q const &key)
 Checks whether the list contains key. More...
 
template<typename Q , typename Less >
bool contains (Q const &key, Less pred)
 Checks whether the map contains key using pred predicate for searching. More...
 
template<typename Q , typename Func >
bool find (Q const &key, Func f)
 Finds key and performs an action with it. More...
 
template<typename Q , typename Less , typename Func >
bool find_with (Q const &key, Less pred, Func f)
 Finds the key val using pred predicate for searching. More...
 
template<typename K >
raw_ptr get (K const &key)
 Finds key and return the item found. More...
 
template<typename K , typename Less >
raw_ptr get_with (K const &key, Less pred)
 Finds key and return the item found. More...
 
bool empty () const
 Checks if the list is empty.
 
size_t size () const
 Returns list's item count. More...
 
stat const & statistics () const
 Returns const reference to internal statistics.
 
void clear ()
 Clears the list. More...
 

Static Public Attributes

static constexpr const bool c_bExtractLockExternal = base_class::c_bExtractLockExternal
 Group of extract_xxx functions do not require external locking.
 

Forward iterators

typedef iterator_type< false > iterator
 Forward iterator. More...
 
typedef iterator_type< true > const_iterator
 Const forward iterator.
 
iterator begin ()
 Returns a forward iterator addressing the first element in a list. More...
 
iterator end ()
 Returns an iterator that addresses the location succeeding the last element in a list. More...
 
const_iterator begin () const
 Returns a forward const iterator addressing the first element in a list.
 
const_iterator cbegin () const
 Returns a forward const iterator addressing the first element in a list.
 
const_iterator end () const
 Returns an const iterator that addresses the location succeeding the last element in a list.
 
const_iterator cend () const
 Returns an const iterator that addresses the location succeeding the last element in a list.
 

Additional Inherited Members

- Protected Types inherited from cds::intrusive::MichaelList< cds::urcu::gc< RCU >, implementation_defined, Traits >
typedef node_type::atomic_marked_ptr atomic_node_ptr
 Atomic node pointer.
 
typedef node_type::marked_ptr marked_node_ptr
 Node marked pointer.
 
typedef atomic_node_ptr auxiliary_head
 Auxiliary head type (for split-list support)
 
typedef implementation_defined value_type
 type of value stored in the list
 
typedef Traits traits
 Traits template parameter.
 
typedef traits::hook hook
 hook type
 
typedef hook::node_type node_type
 node type
 
typedef implementation_defined key_comparator
 key comparison functor based on opt::compare and opt::less option setter.
 
typedef traits::disposer disposer
 disposer used
 
typedef traits::stat stat
 Internal statistics.
 
typedef get_node_traits< value_type, node_type, hook >::type node_traits
 node traits
 
typedef michael_list::get_link_checker< node_type, traits::link_checker >::type link_checker
 link checker
 
typedef cds::urcu::gc< RCU > gc
 Garbage collector.
 
typedef traits::back_off back_off
 back-off strategy
 
typedef traits::item_counter item_counter
 Item counting policy used.
 
typedef traits::memory_model memory_model
 Memory ordering. See cds::opt::memory_model option.
 
typedef gc::template guarded_ptr< value_typeguarded_ptr
 Guarded pointer.
 
typedef iterator_type< false > iterator
 Forward iterator. More...
 
typedef iterator_type< true > const_iterator
 Const forward iterator. More...
 
- Protected Member Functions inherited from cds::intrusive::MichaelList< cds::urcu::gc< RCU >, implementation_defined, Traits >
 MichaelList ()
 Default constructor initializes empty list.
 
 ~MichaelList ()
 Destroys the list object.
 
bool insert (value_type &val)
 Inserts new node. More...
 
bool insert (value_type &val, Func f)
 Inserts new node. More...
 
std::pair< bool, bool > update (value_type &val, Func func, bool bInsert=true)
 Updates the node. More...
 
bool unlink (value_type &val)
 Unlinks the item val from the list. More...
 
bool erase (Q const &key)
 Deletes the item from the list. More...
 
bool erase (Q const &key, Func func)
 Deletes the item from the list. More...
 
bool erase_with (Q const &key, Less pred)
 Deletes the item from the list using pred predicate for searching. More...
 
bool erase_with (Q const &key, Less pred, Func f)
 Deletes the item from the list using pred predicate for searching. More...
 
guarded_ptr extract (Q const &key)
 Extracts the item from the list with specified key. More...
 
guarded_ptr extract_with (Q const &key, Less pred)
 Extracts the item using compare functor pred. More...
 
bool find (Q &key, Func f)
 Finds key in the list. More...
 
bool find_with (Q &key, Less pred, Func f)
 Finds the key using pred predicate for searching. More...
 
bool contains (Q const &key)
 Checks whether the list contains key. More...
 
bool contains (Q const &key, Less pred)
 Checks whether the list contains key using pred predicate for searching. More...
 
guarded_ptr get (Q const &key)
 Finds the key and return the item found. More...
 
guarded_ptr get_with (Q const &key, Less pred)
 Finds the key and return the item found. More...
 
void clear ()
 Clears the list. More...
 
bool empty () const
 Checks whether the list is empty.
 
size_t size () const
 Returns list's item count. More...
 
stat const & statistics () const
 Returns const reference to internal statistics.
 
iterator begin ()
 Returns a forward iterator addressing the first element in a list. More...
 
const_iterator begin () const
 Returns a forward const iterator addressing the first element in a list.
 
iterator end ()
 Returns an iterator that addresses the location succeeding the last element in a list. More...
 
const_iterator end () const
 Returns an const iterator that addresses the location succeeding the last element in a list.
 
const_iterator cbegin () const
 Returns a forward const iterator addressing the first element in a list.
 
const_iterator cend () const
 Returns an const iterator that addresses the location succeeding the last element in a list.
 
- Protected Attributes inherited from cds::intrusive::MichaelList< cds::urcu::gc< RCU >, implementation_defined, Traits >
atomic_node_ptr m_pHead
 Head pointer.
 
item_counter m_ItemCounter
 Item counter.
 
stat m_Stat
 Internal statistics.
 
- Static Protected Attributes inherited from cds::intrusive::MichaelList< cds::urcu::gc< RCU >, implementation_defined, Traits >
static constexpr const size_t c_nHazardPtrCount
 Count of hazard pointer required for the algorithm.
 

Detailed Description

template<typename RCU, typename Key, typename Value, typename Traits = michael_list::traits>
class cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >

Michael's ordered list (key-value pair), template specialization for RCU.

This is key-value variation of non-intrusive MichaelList. Like standard container, this implementation split a value stored into two part - constant key and alterable value.

Usually, ordered single-linked list is used as a building block for the hash table implementation. The complexity of searching is O(N).

Template arguments:

  • RCU - one of RCU type
  • Key - key type of an item stored in the list. It should be copy-constructible
  • Value - value type stored in a list
  • Traits - type traits, default is michael_list::traits
Note
Before including <cds/container/michael_kvlist_rcu.h> you should include appropriate RCU header file, see RCU type for list of existing RCU class and corresponding header files.

It is possible to declare option-based list using cds::container::michael_list::make_traits metafunction istead of Traits template argument. For example, the following traits-based declaration of Michael's list

#include <cds/urcu/general_buffered.h>
#include <cds/container/michael_kvlist_rcu.h>
// Declare comparator for the item
struct my_compare {
int operator ()( int i1, int i2 )
{
return i1 - i2;
}
};
// Declare traits
struct my_traits: public cds::container::michael_list::traits
{
typedef my_compare compare;
};
// Declare traits-based list
typedef cds::container::MichaelKVList< cds::urcu::gc< cds::urcu::general_buffered<> >, int, int, my_traits > traits_based_list;

is equivalent for the following option-based list

#include <cds/urcu/general_buffered.h>
#include <cds/container/michael_kvlist_rcu.h>
// my_compare is the same
// Declare option-based list
typedef cds::container::MichaelKVList< cds::urcu::gc< cds::urcu::general_buffered<> >, int, int,
>::type
> option_based_list;

Member Typedef Documentation

§ iterator

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
typedef iterator_type<false> cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::iterator

Forward iterator.

You may safely use iterators in multi-threaded environment only under external RCU lock. Otherwise, a program crash is possible if another thread deletes the item the iterator points to.

Constructor & Destructor Documentation

§ MichaelKVList()

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::MichaelKVList ( )
inline

Default constructor.

Initializes empty list

§ ~MichaelKVList()

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::~MichaelKVList ( )
inline

List destructor.

Clears the list

Member Function Documentation

§ begin()

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
iterator cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::begin ( )
inline

Returns a forward iterator addressing the first element in a list.

For empty list

begin() == end()

§ clear()

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
void cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::clear ( )
inline

Clears the list.

Post-condition: the list is empty

§ contains() [1/2]

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
template<typename Q >
bool cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::contains ( Q const &  key)
inline

Checks whether the list contains key.

The function searches the item with key equal to key and returns true if it is found, and false otherwise.

The function applies RCU lock internally.

§ contains() [2/2]

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
template<typename Q , typename Less >
bool cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::contains ( Q const &  key,
Less  pred 
)
inline

Checks whether the map contains key using pred predicate for searching.

The function is an analog of contains( key ) but pred is used for key comparing. Less functor has the interface like std::less. Less must imply the same element order as the comparator used for building the list.

The function applies RCU lock internally.

§ emplace()

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
template<typename K , typename... Args>
bool cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::emplace ( K &&  key,
Args &&...  args 
)
inline

Inserts data of type mapped_type constructed with std::forward<Args>(args)...

Returns true if inserting successful, false otherwise.

The function applies RCU lock internally.

§ end()

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
iterator cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::end ( )
inline

Returns an iterator that addresses the location succeeding the last element in a list.

Do not use the value returned by end function to access any item. Internally, end returning value equals to nullptr.

The returned value can be used only to control reaching the end of the list. For empty list

begin() == end()

§ erase() [1/2]

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
template<typename K >
bool cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::erase ( K const &  key)
inline

Deletes key from the list.

RCU synchronize method can be called. RCU should not be locked.

Returns true if key is found and has been deleted, false otherwise

§ erase() [2/2]

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
template<typename K , typename Func >
bool cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::erase ( K const &  key,
Func  f 
)
inline

Deletes key from the list.

The function searches an item with key key, calls f functor and deletes the item. If key is not found, the functor is not called.

The functor Func interface:

struct functor {
void operator()(value_type& val) { ... }
};

RCU synchronize method can be called. RCU should not be locked.

Return true if key is found and deleted, false otherwise

See also: erase

§ erase_with() [1/2]

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
template<typename K , typename Less >
bool cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::erase_with ( K const &  key,
Less  pred 
)
inline

Deletes the item from the list using pred predicate for searching.

The function is an analog of erase(K const&) but pred is used for key comparing. Less functor has the interface like std::less. pred must imply the same element order as the comparator used for building the list.

§ erase_with() [2/2]

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
template<typename K , typename Less , typename Func >
bool cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::erase_with ( K const &  key,
Less  pred,
Func  f 
)
inline

Deletes the item from the list using pred predicate for searching.

The function is an analog of erase(K const&, Func) but pred is used for key comparing. Less functor has the interface like std::less. pred must imply the same element order as the comparator used for building the list.

§ extract()

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
template<typename K >
exempt_ptr cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::extract ( K const &  key)
inline

Extracts an item from the list.

The function searches an item with key equal to key in the list, unlinks it from the list, and returns exempt_ptr pointer to the item found. If key is not found the function returns an empty exempt_ptr.

Note
The function does NOT dispose the item found. It just excludes the item from the list and returns a pointer to item found. You shouldn't lock RCU before calling this function.
#include <cds/urcu/general_buffered.h>
#include <cds/container/michael_kvlist_rcu.h>
typedef cds::urcu::gc< general_buffered<> > rcu;
rcu_michael_list theList;
// ...
rcu_michael_list::exempt_ptr p;
// The RCU should NOT be locked when extract() is called!
assert( !rcu::is_locked());
// extract() call
p = theList.extract( 10 );
if ( p ) {
// do something with p
...
}
// we may safely release extracted pointer here.
// release() passes the pointer to RCU reclamation cycle.
p.release();

§ extract_with()

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
template<typename K , typename Less >
exempt_ptr cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::extract_with ( K const &  key,
Less  pred 
)
inline

Extracts an item from the list using pred predicate for searching.

This function is the analog for extract(K const&). The pred is a predicate used for key comparing. Less has the interface like std::less. pred must imply the same element order as key_comparator.

§ find()

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
template<typename Q , typename Func >
bool cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::find ( Q const &  key,
Func  f 
)
inline

Finds key and performs an action with it.

The function searches an item with key equal to key and calls the functor f for the item found. The interface of Func functor is:

struct functor {
void operator()( value_type& item );
};

where item is the item found.

The functor may change item.second that is reference to value of node. Note that the function is only guarantee that item cannot be deleted during functor is executing. The function does not serialize simultaneous access to the list item. If such access is possible you must provide your own synchronization schema to exclude unsafe item modifications.

The function makes RCU lock internally.

The function returns true if key is found, false otherwise.

§ find_with()

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
template<typename Q , typename Less , typename Func >
bool cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::find_with ( Q const &  key,
Less  pred,
Func  f 
)
inline

Finds the key val using pred predicate for searching.

The function is an analog of find(Q const&, Func) but pred is used for key comparing. Less functor has the interface like std::less. pred must imply the same element order as the comparator used for building the list.

§ get()

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
template<typename K >
raw_ptr cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::get ( K const &  key)
inline

Finds key and return the item found.

The function searches the item with key and returns the pointer to item found. If key is not found it returns an empty raw_ptr object.

Note the compare functor should accept a parameter of type K that can be not the same as key_type.

RCU should be locked before call of this function. Returned item is valid only while RCU is locked:

typedef cds::container::MichaelKVList< cds::urcu::gc< cds::urcu::general_buffered<> >, int, foo, my_traits > ord_list;
ord_list theList;
// ...
tyename ord_list::raw_ptr rp;
{
// Lock RCU
ord_list::rcu_lock lock;
rp = theList.get( 5 );
if ( rp ) {
// Deal with rp
//...
}
// Unlock RCU by rcu_lock destructor
}
// rp can be released at any time after RCU has been unlocked
rp.release();

§ get_with()

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
template<typename K , typename Less >
raw_ptr cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::get_with ( K const &  key,
Less  pred 
)
inline

Finds key and return the item found.

The function is an analog of get(K const&) but pred is used for comparing the keys.

Less functor has the semantics like std::less but should take arguments of type key_type and K in any order. pred must imply the same element order as the comparator used for building the list.

§ insert() [1/2]

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
template<typename K >
bool cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::insert ( const K &  key)
inline

Inserts new node with key and default value.

The function creates a node with key and default value, and then inserts the node created into the list.

Preconditions:

  • The key_type should be constructible from value of type K. In trivial case, K is equal to key_type.
  • The mapped_type should be default-constructible.

The function applies RCU lock internally.

Returns true if inserting successful, false otherwise.

§ insert() [2/2]

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
template<typename K , typename V >
bool cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::insert ( const K &  key,
const V &  val 
)
inline

Inserts new node with a key and a value.

The function creates a node with key and value val, and then inserts the node created into the list.

Preconditions:

  • The key_type should be constructible from key of type K.
  • The mapped_type should be constructible from val of type V.

The function applies RCU lock internally.

Returns true if inserting successful, false otherwise.

§ insert_with()

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
template<typename K , typename Func >
bool cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::insert_with ( const K &  key,
Func  func 
)
inline

Inserts new node and initialize it by a functor.

This function inserts new node with key key and if inserting is successful then it calls func functor with signature

struct functor {
void operator()( value_type& item );
};

The argument item of user-defined functor func is the reference to the list's item inserted. item.second is a reference to item's value that may be changed. User-defined functor func should guarantee that during changing item's value no any other changes could be made on this list's item by concurrent threads.

The key_type should be constructible from value of type K.

The function allows to split creating of new item into two part:

  • create item from key;
  • insert new item into the list;
  • if inserting is successful, initialize the value of item by calling func functor

This can be useful if complete initialization of object of mapped_type is heavyweight and it is preferable that the initialization should be completed only if inserting is successful.

The function applies RCU lock internally.

Warning
See insert item troubleshooting

§ size()

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
size_t cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::size ( ) const
inline

Returns list's item count.

The value returned depends on item counter provided by Traits. For atomicity::empty_item_counter, this function always returns 0.

Note
Even if you use real item counter and it returns 0, this fact does not mean that the list is empty. To check list emptyness use empty() method.

§ update()

template<typename RCU , typename Key , typename Value , typename Traits = michael_list::traits>
template<typename K , typename Func >
std::pair<bool, bool> cds::container::MichaelKVList< cds::urcu::gc< RCU >, Key, Value, Traits >::update ( const K &  key,
Func  func,
bool  bAllowInsert = true 
)
inline

Updates an element with given key.

The operation performs inserting or changing data with lock-free manner.

If the key not found in the list, then the new item created from key is inserted into the list (note that in this case the key_type should be copy-constructible from type K). Otherwise, the functor func is called with item found. The functor Func may be a function with signature:

void func( bool bNew, value_type& item );

or a functor:

struct my_functor {
void operator()( bool bNew, value_type& item );
};

with arguments:

  • bNew - true if the item has been inserted, false otherwise
  • item - item of the list

The functor may change any fields of the item.second that is mapped_type; however, func must guarantee that during changing no any other modifications could be made on this item by concurrent threads.

The function applies RCU lock internally.

Returns std::pair<bool, bool> where first is true if operation is successful, second is true if new item has been added or false if the item with key already is in the list.

Warning
See insert item troubleshootingUpdates data by key The operation performs inserting or replacing the element with lock-free manner.

If the key not found in the list, then the new item created from key will be inserted iff bAllowInsert is true. (note that in this case the key_type should be constructible from type K). Otherwise, if key is found, the functor func is called with item found.

The functor Func signature is:

struct my_functor {
void operator()( bool bNew, value_type& item );
};

with arguments:

  • bNew - true if the item has been inserted, false otherwise
  • item - the item found or inserted

The functor may change any fields of the item.second that is mapped_type; however, func must guarantee that during changing no any other modifications could be made on this item by concurrent threads.

The function applies RCU lock internally.

Returns std::pair<bool, bool> where first is true if operation is successful, second is true if new item has been added or false if the item with key already exists.

Warning
See insert item troubleshooting

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

cds 2.2.0 Developed by Maxim Khizhinsky aka khizmax 2007 - 2017
Autogenerated Wed Jan 4 2017 08:49:38 by Doxygen 1.8.12