multifunction_node

[flow_graph.multifunction_node]

A node that used for nodes that receive messages at a single input port and may generate one or more messages that are broadcast to successors.

// Defined in header <tbb/flow_graph.h>

namespace tbb {
namespace flow {

    template < typename Input, typename Output, typename Policy = /*implementation-defined*/ >
    class multifunction_node : public graph_node, public receiver<Input> {
    public:
        template<typename Body>
        multifunction_node( graph &g, size_t concurrency, Body body, Policy /*unspecified*/ = Policy(),
                            node_priority_t priority = no_priority );
        template<typename Body>
        multifunction_node( graph &g, size_t concurrency, Body body,
                            node_priority_t priority = no_priority );

        multifunction_node( const multifunction_node& other );
        ~multifunction_node();

        bool try_put( const Input &v );

        using output_ports_type = /*implementation-defined*/;
        output_ports_type& output_ports();
    };

} // namespace flow
} // namespace tbb

Requirements:

multifunction_node has a user-settable concurrency limit. It can be set to one of predefined values. The user can also provide a value of type std::size_t to limit concurrency to a value between 1 and tbb::flow::unlimited.

When the concurrency limit allows, it executes the user-provided body on incoming messages. The body may create one or more output messages and broadcast them to successors.

multifunction_node is a graph_node, receiver<InputType> and has a tuple of sender<Output> outputs.

multifunction_node has a discarding and broadcast-push properties.

The body object passed to a multifunction_node is copied. Therefore updates to member variables will not affect the original object used to construct the node. If the state held within a body object must be inspected from outside of the node, the copy_body function can be used to obtain an updated copy.

Member types

output_ports_type is an alias to a tuple of output ports.

Member functions

template<typename Body>
multifunction_node( graph &g, size_t concurrency, Body body,
                    node_priority_t priority = no_priority );

Constructs a multifunction_node that will invoke a copy of body. At most concurrency calls to body may be made concurrently.

Allows to specify node priority.

template<typename Body>
multifunction_node( graph &g, size_t concurrency, Body body, Policy /*unspecified*/ = Policy(),
                    node_priority_t priority = no_priority );

Constructs a multifunction_node that will invoke a copy of body. At most concurrency calls to body may be made concurrently.

Allows to specify a policy and node priority.

multifunction_node( const multifunction_node &src )

Constructs a multifunction_node that has the same initial state that other had when it was constructed. The multifunction_node that is constructed will have a reference to the same graph object as other, will have a copy of the initial body used by other, and have the same concurrency threshold as other. The predecessors and successors of other will not be copied.

The new body object is copy-constructed from a copy of the original body provided to other at its construction. Therefore changes made to member variables in other’s body after the construction of other will not affect the body of the new multifunction_node.

bool try_put( const input_type &v )

If concurrency limit allows, executes the user-provided body on incoming messages and returns true. Otherwise executes nothing and return false.

output_ports_type& output_ports();

Returns: a tuple of output ports.