asio C++ library


defer (2 of 3 overloads)

Submits a completion token or function object for execution.

    typename Executor,
    typename NullaryToken = DEFAULT>
DEDUCED defer(
    const Executor & ex,
    NullaryToken && token = DEFAULT,
    typename constraint< execution::is_executor< Executor >::value||is_executor< Executor >::value >::type  = 0);

This function submits an object for execution using the specified executor. The function object is queued for execution, and is never called from the current thread prior to returning from defer().

The use of defer(), rather than post, indicates the caller's preference that the executor defer the queueing of the function object. This may allow the executor to optimise queueing for cases when the function object represents a continuation of the current call context.



The target executor.


The completion token that will be used to produce a completion handler. The function signature of the completion handler must be:

void handler();
Return Value

This function returns async_initiate<NullaryToken, void()>(Init{ex}, token), where Init is a function object type defined as:

class Init
  using executor_type = Executor;
  explicit Init(const Executor& ex) : ex_(ex) {}
  executor_type get_executor() const noexcept { return ex_; }
  template <typename CompletionHandler>
    void operator()(CompletionHandler&& completion_handler) const;
  Executor ex_; // exposition only

The function call operator of Init:

Completion Signature