EventThreadPool Class Reference

#include <evo/event_thread.h>

Inheritance diagram for EventThreadPool:

Detailed Description

Event processing thread pool.

• This runs a group of threads as EventQueue consumers that process events added to the queue
• Events are popped from the queue and invoked by a thread in the pool, then are destroyed (if event returns true)
• Use start() to start threads, and shutdown() and join() to shutdown
• Use add() to add events to queue

Example

#include <evo/event_thread.h>
using namespace evo;

struct MyEvent : Event {
    bool operator()() {
        // ...
        return true;
    }
};

int main() {
    // Setup
    EventThreadPool threadpool;
    threadpool.start(2);

    // Add an event to invoke in thread pool
    threadpool.add(new MyEvent);

    // Shutdown
    threadpool.shutdown().join();
    return 0;
}

Public Types
typedef MutexInert	MutexT
	Mutex type More...
typedef EventThreadState	SharedState
	Thread shared state More...
typedef EventThreadPool	This
	This type. More...
typedef Thread::Init	ThreadInit
	Thread init type More...

Public Member Functions
	EventThreadPool (ulong wait_timeout_ms=1)
	Constructor. More...
bool	active () const
	Get whether thread group is active (threads running). More...
This &	add (Event *event, ulongl spinwait_ns=1)
	Add an event to queue to be processed. More...
bool	join ()
	Join all threads by waiting for them to stop. More...
This &	shutdown ()
	Stop processing events and shutdown threads. More...
ulong	size () const
	Get thread group size. More...
bool	start (uint count=1)
	Create new threads, add to group and start them. More...

Public Attributes
SharedState	shared_state
	Shared state used by threads. More...
ThreadInit	thread_init
	Thread init values for function-based threads, not used for class-based threads More...

Protected Types
typedef impl::ThreadGroupNode< EventThreadState, Thread >	Node

Protected Attributes
bool	active_
bool	cancel_flag_
Node *	first_
Node *	last_
MutexT	mutex_
ulong	size_

Member Typedef Documentation

MutexT

typedef MutexInert MutexT

inherited

Mutex type

Node

typedef impl::ThreadGroupNode<EventThreadState ,Thread > Node

protectedinherited

SharedState

typedef EventThreadState SharedState

inherited

Thread shared state

This

typedef EventThreadPool This

This type.

ThreadInit

typedef Thread::Init ThreadInit

inherited

Thread init type

Constructor & Destructor Documentation

EventThreadPool()

EventThreadPool ( ulong  wait_timeout_ms = 1 )

inline

Constructor.

Parameters

wait_timeout_ms

Maximum thread wait while idle – see waitms in EventQueue::process_multiwait()

Member Function Documentation

active()

bool active ( ) const

inlineinherited

Get whether thread group is active (threads running).

• The group is active when at least 1 thread is started, and inactive once join() returns
• The group does not become inactive until join() is called, even if all threads finished

Returns

Whether active

add()

This& add ( Event *  event, ulongl  spinwait_ns = 1  )

inline

Add an event to queue to be processed.

• This takes ownership of the event pointer, and will free it once the event is completed (via C++ delete operator)
  • The event is only freed if it returns true, otherwise it's assumed that ownership was transferred elsewhere
• This blocks while queue is full (spin-wait with 1 nanosecond sleep) – a full queue should be avoided
• Caution: Do not call from the same queue that invoked (called) the event, this will deadlock if the queue is full

Parameters

event	Event pointer to add and take ownership of
spinwait_ns	Spin-wait sleep time in nanoseconds (usually default is preferred) – used to sleep each loop while spin waiting

Returns

This

join()

bool join ( )

inlineinherited

Join all threads by waiting for them to stop.

Returns

Always true

shutdown()

This& shutdown ( )

inline

Stop processing events and shutdown threads.

• This starts the shutdown process, call join() to wait for all threads to fully stop
• Stop adding events to the queue before calling this, otherwise behavior is undefned (likely shutdown delay or memory leak)

Returns

This

size()

ulong size ( ) const

inlineinherited

Get thread group size.

Returns

Number of threads running

start()

bool start ( uint  count = 1 )

inlineinherited

Create new threads, add to group and start them.

• This may be called multiple times to grow the number of threads
• This fails once cancel() is called, until join() is called to reset
• Fails for function-based threads if thread_init.func isn't set (by constructor or directly)

Parameters

count

Number of threads to add and start

Returns

Whether successful, false on error

Member Data Documentation

active_

bool active_

protectedinherited

cancel_flag_

bool cancel_flag_

protectedinherited

first_

Node* first_

protectedinherited

last_

Node* last_

protectedinherited

mutex_

MutexT mutex_

mutableprotectedinherited

shared_state

SharedState shared_state

inherited

Shared state used by threads.

size_

ulong size_

protectedinherited

thread_init

ThreadInit thread_init

inherited

Thread init values for function-based threads, not used for class-based threads

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The documentation for this class was generated from the following file:

• evo/event_thread.h