Intel® oneAPI Threading Building Blocks Developer Guide and API Reference
task_group_context
[scheduler.task_group_context]
task_group_context represents a set of properties used by task scheduler for execution of the associated tasks. Each task is associated with only one task_group_context object.
The task_group_context objects form a forest of trees. Each tree’s root is a task_group_context constructed as isolated.
task_group_context is cancelled explicitly by the user request, or implicitly when an exception is thrown out of an associated task. Canceling task_group_context causes the entire subtree rooted at it to be cancelled.
The task_group_context carries floating point settings inherited from the parent task_group_context object or captured with a dedicated interface.
// Defined in header <oneapi/tbb/task_group.h>
namespace oneapi {
namespace tbb {
class task_group_context {
public:
enum kind_t {
isolated = /* implementation-defined */,
bound = /* implementation-defined */
};
enum traits_type {
fp_settings = /* implementation-defined */,
default_traits = 0
};
task_group_context( kind_t relation_with_parent = bound,
uintptr_t traits = default_traits );
~task_group_context();
void reset();
bool cancel_group_execution();
bool is_group_execution_cancelled() const;
void capture_fp_settings();
uintptr_t traits() const;
};
} // namespace tbb;
} // namespace oneapiMember types and constants
enumkind_t::isolated
When passed to the specific constructor, the created task_group_context object has no parent.
enumkind_t::bound
When passed to the specific constructor, the created task_group_context object becomes a child of the innermost running task’s group when the first task associated to the task_group_context is passed to the task scheduler. If there is no innermost running task on the current thread, the task_group_context becomes isolated.
enumtraits_type::fp_settings
When passed to the specific constructor, the flag forces the context to capture floating-point settings from the current thread.
Member functions
task_group_context(kind_trelation_to_parent=bound, uintptr_ttraits=default_traits)
Constructs an empty task_group_context.
~task_group_context()
Destroys an empty task_group_context. The behavior is undefined if there are still extant tasks associated with this task_group_context.
boolcancel_group_execution()
Requests that tasks associated with this task_group_context are not executed.
Returns false if this task_group_context is already cancelled; true, otherwise. If concurrently called by multiple threads, exactly one call returns true and the rest return false.
boolis_group_execution_cancelled()const
Returns true if this task_group_context has received the cancellation request.
voidreset()
Reinitializes this task_group_context to the uncancelled state.
voidcapture_fp_settings()
Captures floating-point settings from the current thread.
uintptr_ttraits()const
Returns traits of this task_group_context.