task::then Method

Adds a continuation task to this task.

template<
   typename _Function
>
__declspec(
   noinline
) auto then(const _Function& _Func) const -> typename details::_ContinuationTypeTraits<_Function, _ReturnType>::_TaskOfType;

template<
   typename _Function
>
__declspec(
   noinline
) auto then(const _Function& _Func, const task_options& _TaskOptions) const -> typename details::_ContinuationTypeTraits<_Function, _ReturnType>::_TaskOfType;

template<
   typename _Function
>
__declspec(
   noinline
) auto then(const _Function& _Func, cancellation_token _CancellationToken, task_continuation_context _ContinuationContext) const -> typename details::_ContinuationTypeTraits<_Function, _ReturnType>::_TaskOfType;

template<
   typename _Function
>
__declspec(
   noinline
) auto then(const _Function& _Func, const task_options& _TaskOptions = task_options()) const -> typename details::_ContinuationTypeTraits<_Function, void>::_TaskOfType;

template<
   typename _Function
>
__declspec(
   noinline
) auto then(const _Function& _Func, cancellation_token _CancellationToken, task_continuation_context _ContinuationContext) const -> typename details::_ContinuationTypeTraits<_Function, void>::_TaskOfType;

Parameters

• _Function
  The type of the function object that will be invoked by this task.

• _Func
  The continuation function to execute when this task completes. This continuation function must take as input a variable of either result_type or task<result_type>, where result_type is the type of the result this task produces.

• _TaskOptions
  The task options include cancellation token, scheduler and continuation context. By default the former 3 options are inherited from the antecedent task

• _CancellationToken
  The cancellation token to associate with the continuation task. A continuation task that is created without a cancellation token will inherit the token of its antecedent task.

• _ContinuationContext
  A variable that specifies where the continuation should execute. This variable is only useful when used in a Windows Store style app. For more information, see task_continuation_context

Return Value

The newly created continuation task. The result type of the returned task is determined by what _Func returns.

Remarks

The overloads of then that take a lambda or functor that returns a Windows::Foundation::IAsyncInfo interface, are only available to Windows Store apps.

For more information on how to use task continuations to compose asynchronous work, see Task Parallelism (Concurrency Runtime).

Requirements

Header: ppltasks.h

Namespace: concurrency

See Also

Reference

task Class (Concurrency Runtime)