But it is not available in standard C++ library. In Linux, all thread functions are declared in header file. Each thread shares memory, file descriptors and other system resources. Each thread executes different parts of a program. Thread is generally referred as a light weight process. There are various uses of Multithreading, some of them are: Multithreading environment allows you to run many activities simultaneously where different threads are responsible for different activities. This is the best example of multithreading. When you login to you Facebook profile, on your news feed, you can see live videos, you can comment or hit a like button, everything simultaneously. Multithreading means two or more threads running concurrently where each thread is handling a different task. 100+ C++ Programs with explanation and output.Abstract class and Pure Virtual Functions.On success, pthread_cancel() returns 0 on error, it returns a nonzero error number. (Joining with a thread is the only way to know that cancellation has completed.) RETURN VALUE The above steps happen asynchronously with respect to the pthread_cancel() call the return status of pthread_cancel() merely informs the caller whether the cancellation request was successfully queued.Īfter a canceled thread has terminated, a join with that thread using pthread_join(3) obtains PTHREAD_CANCELED as the thread's exit status. Thread-specific data destructors are called, in an unspecified order. Cancellation clean-up handlers are popped (in the reverse of the order in which they were pushed) and called. When a cancellation requested is acted on, the following steps occur for thread (in this order): 1. A list of functions that are or may be cancellation points is provided in pthreads(7). Deferred cancelability means that cancellation will be delayed until the thread next calls a function that is a cancellation point. Asynchronous cancelability means that the thread can be canceled at any time (usually immediately, but the system does not guarantee this). If a thread has enabled cancellation, then its cancelability type determines when cancellation occurs.Ī thread's cancellation type, determined by pthread_setcanceltype(3), may be either asynchronous or deferred (the default for new threads). If a thread has disabled cancellation, then a cancellation request remains queued until the thread enables cancellation. Whether and when the target thread reacts to the cancellation request depends on two attributes that are under the control of that thread: its cancelability state and type.Ī thread's cancelability state, determined by pthread_setcancelstate(3), can be enabled (the default for new threads) or disabled. The pthread_cancel() function sends a cancellation request to the thread thread.
Join and cancel pthread c code#
The same code runs fine when compiled with gcc 6.3.0Ĭould someone please share some thoughts why this is happening and if it is inherent to the compiler. If there is no local object on the thread stack the program terminates normally and no abort signal is raised. The exception seems to be caused by the existence a local object on the thread stack that would need to have its destructors called. The sleeping thread would then raise an abort signal that would cause the application to terminate abnormally. The following piece of code shows a scenario where the main thread calls pthread_cancel on a background thread that is sleeping.