thread_pool

A simple fixed-size thread pool.

class thread_pool :
  public execution_context

Types

Name	Description
basic_executor_type	Executor implementation type used to submit functions to a thread pool.
executor_type	Executor used to submit functions to a thread pool.
fork_event	Fork-related event notifications.

Member Functions

Name	Description
attach	Attaches the current thread to the pool.
executor	Obtains the executor associated with the pool.
get_executor	Obtains the executor associated with the pool.
join	Joins the threads.
notify_fork	Notify the execution_context of a fork-related event.
stop	Stops the threads.
thread_pool [constructor]	Constructs a pool with an automatically determined number of threads. — Constructs a pool with a specified number of threads.
wait	Waits for threads to complete.
~thread_pool [destructor]	Destructor.

Protected Member Functions

Name	Description
destroy	Destroys all services in the context.
shutdown	Shuts down all services in the context.

The thread pool class is an execution context where functions are permitted to run on one of a fixed number of threads.

Shared objects: Safe, with the specific exceptions of the join() wait() and notify_fork() functions. The join() and wait() functions must not be called at the same time as other calls to join() or wait() on the same pool. The notify_fork() function should not be called while any thread_pool function, or any function on an I/O object that is associated with the thread_pool, is being called in another thread. (In effect, this means that notify_fork() is safe only on a thread pool that has no internal or attached threads at the time.)

Submitting tasks to the pool

To submit functions to the thread pool, use the dispatch, post or defer free functions.

For example:

void my_task()
{
  ...
}

...

// Launch the pool with four threads.
boost::asio::thread_pool pool(4);

// Submit a function to the pool.
boost::asio::post(pool, my_task);

// Submit a lambda object to the pool.
boost::asio::post(pool,
    []()
    {
      ...
    });

// Wait for all tasks in the pool to complete.
pool.join();

Requirements

Header: boost/asio/thread_pool.hpp

Convenience header: boost/asio.hpp

Boost C++ Libraries