Function query

3rd/asio-1.24.0/include/asio/thread_pool.hpp:557–560

Query the occupancy (recommended number of work items) for the pool. * Do not call this function directly. It is intended for use with the * asio::query customisation point. * * For example: * @code auto ex = my_thread_pool.executor(); * std::size_t occupancy = asio::query( * ex, asio::execution::occupancy); @endcode */

   *     ex, asio::execution::occupancy); @endcode
   */
  std::size_t query(execution::occupancy_t) const ASIO_NOEXCEPT
  {
    return static_cast<std::size_t>(pool_->num_threads_);
  }

public:
  /// Determine whether the thread pool is running in the current thread.