This templatized class provides synchronized access to guarded objects in a multithreaded environment. In addition, os_sentinel can provide change notification to blocked threads when the guarded object is modified. Change detection occurs when the guarded object is released from a lock and does not incur the overhead of a true comparison operation.

Interface

Constructor

os_sentinel( T& object )

Constructs a sentinel to guard access to object .

Throws: os_thread_toolkit_error

const T& operator*() const

Returns a constant reference to the guarded object.

T& operator*()

Returns a reference to the guarded object.

const T* operator->() const

Returns a constant pointer to the guarded object.

T* operator->()

Returns a pointer to the guarded object.

lock

void lock()

Acquires the lock, blocking if necessary. Depending upon the underlying platform, the lock attempt will fail or the thread will deadlock if it tries to obtain a mutex that it already owns.

Throws: os_thread_toolkit_error

notify

void notify()

Signals a change in the state of the guarded object, awakening all waiting threads. Calling notify() has no effect if there are no threads waiting. The calling thread must own the lock associated with the sentinel when calling this member function to provide predictable scheduling of awakened threads and to guarantee proper internal synchronization. The behavior of this member function is undefined if the calling thread does not own the lock.

Throws: os_thread_toolkit_error

notify_unlock

void notify_unlock()

Performs the same function as notify() , but then releases the lock afterwards.

Throws: os_thread_toolkit_error

observe

void observe()

Blocks until the guarded object is modified.

Throws: os_thread_toolkit_error

try_lock

bool try_lock()

Attempts to acquire the lock. Instead of blocking, this function returns false if it fails to acquire a lock immediately.

Throws: os_thread_toolkit_error

unlock

void unlock()

Releases the lock.

Throws: os_thread_toolkit_error

wait

void wait()

Synonym for observe() ; alternative event syntax.

Throws: os_thread_toolkit_error

sentinel

Library

Declaration

Interface