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s3_mutex Class Reference

A mutex (MUTual EXclusion primitive) that is implemented as a wrapper around pthread_mutex_t. More...

#include <s3_mutex.h>

List of all members.

Public Methods
	s3_mutex ()
	Default constructor: instantiate a new mutex. More...
	~s3_mutex ()
	Destructor: destroy the mutex primitive. More...
void	lock () const
	Attempt to lock the mutex. More...
bool	try_lock () const
	Attempt to lock the mutex, but immediately return a false if it is already locked. More...
void	unlock () const
	Unlock the mutex (please read note about unlocking in s3_mutex class documentation.. More...
Protected Methods
	s3_mutex (const s3_mutex &src)
	Copy constructor: private for your convenience (thou shalt not copy construct an s3_mutex - deal with it). More...
s3_mutex &	operator= (const s3_mutex &src)
	Neither shalt thou copy assign an s3_mutex. More...
Protected Attributes
pthread_mutex_t	mutex
	LinuxThreads mutex primitive. More...
Friends
class	s3_condition

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Detailed Description

A mutex (MUTual EXclusion primitive) that is implemented as a wrapper around pthread_mutex_t.

Note: only the fast mutex kind is implemented.

A mutex is a primitive that is either in a locked or unlocked state and is always owned by a single process when it is locked. Otherwise it is not owned. The following operations are supported (assumes a fast mutex):

• lock:
  • if the mutex is currently locked (i.e.owned by a process):
• suspend the caller until the mutex becomes unlocked
  • lock the mutex and obtain ownership of it.
• else:
  • lock the mutex and obtain ownership of it
• unlock:
  • unlock the mutex and relinquish ownership.
• try_lock:
  • if the mutex is currently locked (i.e. owned by a process):
  • return immediately and indicate this condition
  • else:
  • lock the mutex and obtain ownership of it

All the above operations are atomic.

Note: The following rules must be obeyed when calling unlock:

• Only the process that locked the mutex (i.e. the owner) may unlock it.
• Unlock may not be called on an already unlocked mutex. Violating any of these rules has undefined behaviour and it should therefore never happen.

All the member functions are declared const and a semaphore can therefore always be used in a const context.

Definition at line 75 of file s3_mutex.h.

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Constructor & Destructor Documentation

s3_mutex::s3_mutex (    )

Default constructor: instantiate a new mutex. Definition at line 44 of file s3_mutex.cc. References CONST_OVERRIDE_MUTEX_T, and mutex.

s3_mutex::~s3_mutex (    )

Destructor: destroy the mutex primitive. Definition at line 51 of file s3_mutex.cc. References CONST_OVERRIDE_MUTEX_T, mutex, and unlock.

s3_mutex::s3_mutex (  const s3_mutex &    src )  [protected]

Copy constructor: private for your convenience (thou shalt not copy construct an s3_mutex - deal with it). Definition at line 63 of file s3_mutex.cc.

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Member Function Documentation

void s3_mutex::lock (    )  const

Attempt to lock the mutex. If it is already locked, block until it becomes available and then lock it and return. Definition at line 77 of file s3_mutex.cc. References CONST_OVERRIDE_MUTEX_T, and mutex. Referenced by s3_periodic_notifier::event_loop::add_client, s3_post_office::add_dst, s3_txport_tcp_rx_task::cleanup, s3_txport_tcp::clear_critical_by_id, s3_periodic_notifier::event_loop::clients, s3_txport_local::connect, s3_txport_tcp_rx_task::connected, s3_inplace_fifo_mux::create_vqueue, s3_message_box::deliver_msg, s3_txport_local::deregister_me, s3_inplace_fifo_mux::destroy_vqueue, s3_periodic_notifier::disable, s3_txport_tcp::disconnect_by_id, s3_txport_local::disconnect_by_id, s3_event_dispatcher::dispatch_event, s3_periodic_notifier::enable, s3_txport_tcp::get_client_id_list, s3_txport_local::get_client_id_list, s3_txport_tcp::get_ip_address_by_id, s3_message_box::get_msg, s3_txport_tcp::get_socket_by_id, s3_txport_tcp::is_connected_by_id, s3_txport_local::is_connected_by_id, s3_inplace_fifo_mux::is_started, s3_event_dispatcher::is_subscribed, s3_subscribable_fifo::is_subscribed_consumer, s3_subscribable_fifo::is_subscribed_producer, s3_thread_base::lock_state, s3_txport_local::main_loop, s3_periodic_notifier::event_loop::main_loop, s3_periodic_notifier::notify, s3_subscribable_fifo::notify_consumers, s3_subscribable_fifo::notify_producers, s3_txport_tcp::num_connections, s3_txport_local::num_connections, s3_txport_tcp::reap, s3_txport_local::register_me, s3_periodic_notifier::event_loop::remove_client, s3_post_office::remove_dst, s3_thread_base::request_terminate, s3_periodic_notifier::s3_periodic_notifier, s3_txport_local::send_metadata, s3_txport_tcp::set_critical_by_id, s3_periodic_notifier::set_period, s3_periodic_notifier::event_loop::set_period, s3_inplace_fifo_mux::set_queue, s3_txport_tcp::spawn_handler, s3_inplace_fifo_mux::start, s3_inplace_fifo_mux::stop, s3_periodic_notifier::subscribe, s3_subscribable_fifo::subscribe_consumer, s3_event_dispatcher::subscribe_handler, s3_subscribable_fifo::subscribe_producer, s3_thread_base::test_terminate, s3_periodic_notifier::unsubscribe, s3_subscribable_fifo::unsubscribe_consumer, s3_event_dispatcher::unsubscribe_handler, s3_subscribable_fifo::unsubscribe_producer, s3_log_buffer::write_to_device, and s3_periodic_notifier::~s3_periodic_notifier.

s3_mutex & s3_mutex::operator= (  const s3_mutex &    src )  [protected]

Neither shalt thou copy assign an s3_mutex. Definition at line 70 of file s3_mutex.cc.

bool s3_mutex::try_lock (    )  const

Attempt to lock the mutex, but immediately return a false if it is already locked. If it is unlocked, it is locked as if lock was called. Return values: c  true Mutex was unlocked and is now locked by caller (proceeded like wait). c  false Mutex was already locked (skirted the suspend). Definition at line 87 of file s3_mutex.cc. References CONST_OVERRIDE_MUTEX_T, and mutex. Referenced by s3_thread_base::test_state.

void s3_mutex::unlock (    )  const

Unlock the mutex (please read note about unlocking in s3_mutex class documentation.. Definition at line 116 of file s3_mutex.cc. References CONST_OVERRIDE_MUTEX_T, and mutex. Referenced by s3_periodic_notifier::event_loop::add_client, s3_post_office::add_dst, s3_txport_tcp_rx_task::cleanup, s3_txport_tcp::clear_critical_by_id, s3_periodic_notifier::event_loop::clients, s3_txport_local::connect, s3_txport_tcp_rx_task::connected, s3_inplace_fifo_mux::create_vqueue, s3_message_box::deliver_msg, s3_txport_local::deregister_me, s3_inplace_fifo_mux::destroy_vqueue, s3_periodic_notifier::disable, s3_txport_tcp::disconnect_by_id, s3_txport_local::disconnect_by_id, s3_event_dispatcher::dispatch_event, s3_periodic_notifier::enable, s3_txport_tcp::get_client_id_list, s3_txport_local::get_client_id_list, s3_txport_tcp::get_ip_address_by_id, s3_message_box::get_msg, s3_txport_tcp::get_socket_by_id, s3_txport_tcp::is_connected_by_id, s3_txport_local::is_connected_by_id, s3_inplace_fifo_mux::is_started, s3_event_dispatcher::is_subscribed, s3_subscribable_fifo::is_subscribed_consumer, s3_subscribable_fifo::is_subscribed_producer, s3_txport_local::main_loop, s3_periodic_notifier::event_loop::main_loop, s3_periodic_notifier::notify, s3_subscribable_fifo::notify_consumers, s3_subscribable_fifo::notify_producers, s3_txport_tcp::num_connections, s3_txport_local::num_connections, s3_txport_tcp::reap, s3_txport_local::register_me, s3_periodic_notifier::event_loop::remove_client, s3_post_office::remove_dst, s3_thread_base::request_terminate, s3_periodic_notifier::s3_periodic_notifier, s3_txport_local::send_metadata, s3_txport_tcp::set_critical_by_id, s3_periodic_notifier::set_period, s3_periodic_notifier::event_loop::set_period, s3_inplace_fifo_mux::set_queue, s3_txport_tcp::spawn_handler, s3_inplace_fifo_mux::start, s3_inplace_fifo_mux::stop, s3_periodic_notifier::subscribe, s3_subscribable_fifo::subscribe_consumer, s3_event_dispatcher::subscribe_handler, s3_subscribable_fifo::subscribe_producer, s3_thread_base::test_terminate, s3_thread_base::unlock_state, s3_periodic_notifier::unsubscribe, s3_subscribable_fifo::unsubscribe_consumer, s3_event_dispatcher::unsubscribe_handler, s3_subscribable_fifo::unsubscribe_producer, s3_log_buffer::write_to_device, ~s3_mutex, and s3_periodic_notifier::~s3_periodic_notifier.

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Friends And Related Function Documentation

friend class s3_condition [friend]

Definition at line 78 of file s3_mutex.h.

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Member Data Documentation

pthread_mutex_t s3_mutex::mutex [protected]

LinuxThreads mutex primitive. Definition at line 83 of file s3_mutex.h. Referenced by lock, s3_mutex, try_lock, unlock, s3_condition::wait, and ~s3_mutex.

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

• s3_mutex.h
• s3_mutex.cc

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