Unblocks a thread blocked on pthread_cond_wait Unlocks a mutex previously locked by pthread_mutex_lock Initializes a mutex using a provided attribute structure Releases a previously acquired mutex locked by WaitForSingleObject
Releases resources allocated to a Windows handle Sets the stack size value of the thread attribute structure Sets a thread attribute structure to default The following table is a list of the various functions used to implement threading in the CMutexClass, CEventClass, CTask, and CThread classes. They allow one thread to notify another that a change has occurred. Condition variables allow threads to rendezvous. Like mutexes, condition variables, in UNIX, are another form of synchronization mechanism. Thread B is blocked trying to acquire mutex(1), which is blocked by thread A. Example: Thread AĪ deadlock occurs in the example above because thread A is blocked trying to acquire mutex(2), which is held by thread B. Resource starvation occurs when one or more threads are competing for the same resource. Poor implementations of mutexes can result in resource starvation, also known as deadlock. Once a thread has completed data access, it releases the corresponding mutex this allows other threads to acquire it and access the corresponding data. Once a thread has acquired a mutex, other threads attempting to acquire the same mutex are blocked, and placed in a low-CPU usage wait state. When a thread needs access to a resource, it must first acquire a mutex. In multi-threaded applications, mutexes, deployed programmatically, prevent multiple threads from accessing a single resource at the same time. To prevent this scenario, the OS provides a Mutual Exclusion Object, known in short as a mutex. A loss of data integrity occurs when one thread is modifying a variable while another thread is attempting to read it, or two threads are attempting to modify the same variable at the same time. Resource Management-Thread Synchronizationīecause threads within a multi-threaded process share the same resources, OS level control mechanisms are necessary to ensure data integrity. A multi-threaded process allows multiple tasks to run asynchronously from within the environment of the process. A process that has more than one thread of control defines a multi-threaded process. What is Threading?Įvery process has at least one thread of control, and every process can perform at least one task at a time. The CMutexClass and CEventClass provide resource management, while the CTask class is a base class for deriving classes that support homogeneous asynchronous threading. These include the CMutexClass, CEventClass, and CTask classes. To support the new class, CThread, other supporting classes were also developed.
It supports both event driven and interval based asynchronous threading.He wanted a thread class that had the following attributes: Although there are many excellent examples of object-oriented threading on CodeProject, none of the classes introduced suited all of my brother's needs and my curiosities. C has always been my language of choice for low-level programming I use C++ for GUI development. I have written many multi-threaded libraries in the past however, they are all in C. I’m running into an issue which could be due to my use of Task Notifications but I’m unable to confirm.Recently, my brother asked me if there is an easy way to create a C++ class that facilitated object orientated threading.
I am trying to write a small thread abstraction wrapper on top of the freeRTOS implementation and am testing it using the Windows port.