tf::Task Class Reference

class to create a task handle over a node in a taskflow graph More...

#include <task.hpp>

Public Member Functions
	Task ()=default
	constructs an empty task
	Task (const Task &other)
	constructs the task with the copy of the other task
Task &	operator= (const Task &)
	replaces the contents with a copy of the other task
Task &	operator= (std::nullptr_t)
	replaces the contents with a null pointer
bool	operator== (const Task &rhs) const
	compares if two tasks are associated with the same graph node
bool	operator!= (const Task &rhs) const
	compares if two tasks are not associated with the same graph node
const std::string &	name () const
	queries the name of the task
size_t	num_successors () const
	queries the number of successors of the task
size_t	num_dependents () const
	queries the number of predecessors of the task
size_t	num_strong_dependents () const
	queries the number of strong dependents of the task
size_t	num_weak_dependents () const
	queries the number of weak dependents of the task
Task &	name (const std::string &name)
	assigns a name to the task
template<typename C >
Task &	work (C &&callable)
	assigns a callable
template<typename T >
Task &	composed_of (T &object)
	creates a module task from a taskflow
template<typename... Ts>
Task &	precede (Ts &&... tasks)
	adds precedence links from this to other tasks
template<typename... Ts>
Task &	succeed (Ts &&... tasks)
	adds precedence links from other tasks to this
Task &	release (Semaphore &semaphore)
	makes the task release this semaphore
Task &	acquire (Semaphore &semaphore)
	makes the task acquire this semaphore
Task &	data (void *data)
	assigns pointer to user data
void	reset ()
	resets the task handle to null
void	reset_work ()
	resets the associated work to a placeholder
bool	empty () const
	queries if the task handle points to a task node
bool	has_work () const
	queries if the task has a work assigned
template<typename V >
void	for_each_successor (V &&visitor) const
	applies an visitor callable to each successor of the task
template<typename V >
void	for_each_dependent (V &&visitor) const
	applies an visitor callable to each dependents of the task
size_t	hash_value () const
	obtains a hash value of the underlying node
TaskType	type () const
	returns the task type
void	dump (std::ostream &ostream) const
	dumps the task through an output stream
void *	data () const
	queries pointer to user data

Friends
class	FlowBuilder
class	Runtime
class	Taskflow
class	TaskView
class	Executor

Detailed Description

class to create a task handle over a node in a taskflow graph

A task is a wrapper over a node in a taskflow graph. It provides a set of methods for users to access and modify the attributes of the associated node in the taskflow graph. A task is very lightweight object (i.e., only storing a node pointer) that can be trivially copied around, and it does not own the lifetime of the associated node.

Member Function Documentation

composed_of()

template<typename T >

Task & tf::Task::composed_of

(

T &

object

)

creates a module task from a taskflow

Template Parameters

T	object type

Parameters

object

a custom object that defines T::graph() method

Returns

*this

data()

Task & tf::Task::data ( void *  data )

inline

assigns pointer to user data

Parameters

data	pointer to user data

The following example shows how to attach user data to a task and run the task iteratively while changing the data value:

tf::Executor executor;
tf::Taskflow taskflow("attach data to a task");
 
int data;
 
// create a task and attach it the data
auto A = taskflow.placeholder();
A.data(&data).work([A](){
  auto d = *static_cast<int*>(A.data());
  std::cout << "data is " << d << std::endl;
});
 
// run the taskflow iteratively with changing data
for(data = 0; data<10; data++){
  executor.run(taskflow).wait();
}

Returns

*this

name()

Task & tf::Task::name ( const std::string &  name )

inline

assigns a name to the task

Parameters

name	a std::string acceptable string

Returns

*this

precede()

template<typename... Ts>

Task & tf::Task::precede

(

Ts &&...

tasks

)

adds precedence links from this to other tasks

Template Parameters

Ts	parameter pack

Parameters

tasks

one or multiple tasks

Returns

*this

succeed()

template<typename... Ts>

Task & tf::Task::succeed

(

Ts &&...

tasks

)

adds precedence links from other tasks to this

Template Parameters

Ts	parameter pack

Parameters

tasks

one or multiple tasks

Returns

*this

work()

template<typename C >

Task & tf::Task::work

(

C &&

callable

)

assigns a callable

Template Parameters

C	callable type

Parameters

callable

callable to construct one of the static, dynamic, condition, and cudaFlow tasks

Returns

*this

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

• task.hpp