The task_handle class represents an individual parallel work item. It encapsulates the instructions and the data required to execute a piece of work.
template< typename _Function > class task_handle : public ::Concurrency::details::_UnrealizedChore;
The function call operator that the runtime invokes to perform the work of the task handle.
task_handle objects can be used in conjunction with a structured_task_group or a more general task_group object, to decompose work into parallel tasks. For more information, see Task Parallelism (Concurrency Runtime).
Note that the creator of a task_handle object is responsible for maintaining the lifetime of the created task_handle object until it is no longer required by the Concurrency Runtime. Typically, this means that the task_handle object must not destruct until either the wait or run_and_wait method of the task_group or structured_task_group to which it is queued has been called.
task_handle objects are typically used in conjunction with C++ lambdas. Because you do not know the true type of the lambda, the make_task function is typically used to create a task_handle object.
The runtime creates a copy of the work function that you pass to a task_handle object. Therefore, any state changes that occur in a function object that you pass to a task_handle object will not appear in your copy of that function object.