Template class for holding thread-local values during a parallel computation that will be merged into a final value.
template<typename T> class combinable;
#include "tbb/combinable.h"
A combinable<T> provides each thread with its own local instance of type T.
namespace tbb {
template <typename T>
class combinable {
public:
combinable();
template <typename FInit>
combinable(FInit finit);}
combinable(const combinable& other);
~combinable();
combinable& operator=( const combinable& other);
void clear();
T& local();
T& local(bool & exists);
template<typename FCombine> T combine(FCombine fcombine);
template<typename Func> void combine_each(Func f);
};
}
| Member | Description |
|---|---|
| combinable() |
Constructs combinable such that any thread-local instances of T will be created using default construction. |
| template<typename FInit> combinable(FInit finit) |
Constructs combinable such that any thread-local element will be created by copying the result of finit(). CautionThe expression finit() must be safe to evaluate concurrently by multiple threads. It is evaluated each time a thread-local element is created. |
| combinable( const combinable& other ); |
Construct a copy of other, so that it has copies of each element in other with the same thread mapping. |
| ~combinable() |
Destroy all thread-local elements in *this. |
| combinable& operator=( const combinable& other ) |
Set *this to be a copy of other. |
| void clear() |
Remove all elements from *this. |
| T& local() |
If thread-local element does not exist, create it. Returns: Reference to thread-local element. |
| T& local( bool& exists ) |
Similar to local(), except that exists is set to true if an element was already present for the current thread; false otherwise. Returns: Reference to thread-local element. |
| template<typename FCombine>T combine(FCombine fcombine) |
Requires: Parameter fcombine should be an associative binary functor with the signature T(T,T) or T(const T&,const T&). Effects: Computes a reduction over all elements using binary functor fcombine. If there are no elements, creates the result using the same rules as for creating a thread-local element. Returns: Result of the reduction. |
| template<typename Func> void combine_each(Func f) |
Requires: Parameter f should be a unary functor with the signature void(T) or void(const T&). Effects: Evaluates f(x) for each instance x of T in *this. |