What happens if a thread tries to join itself?
Summary of the Article
What happens if a thread tries to join itself?
The call returns immediately indicating an error. The call returns immediately indicating a successful completion. A thread cannot join itself – a deadlock would occur and it is detected by the library.
Can a thread call join on itself?
A thread cannot join itself because a deadlock would occur and it is detected by the library. However, two threads may try to join each other. They will deadlock, but this situation is not detected by the library. The pthread_join subroutine also allows a thread to return information to another thread.
What happens if thread join is not called?
If you don’t join these threads, you might end up using more resources than there are concurrent tasks, making it harder to measure the load. To be clear, if you don’t call join, the thread will complete at some point anyway, it won’t leak or anything. But this some point is non-deterministic.
Is thread join thread safe?
It is not thread safe. If you have more than one thread that can call your snippet at any time, you may experience a race condition. The only real way to protect against this is by wrapping your snippet in an std::mutex shared by the threads calling said snippet.
Can a thread interrupt itself?
The interrupt() method is a method of the Thread class, and it is used by one thread to signal another thread: it is possible (although it doesn’t really make sense) for a thread to interrupt itself. The target thread knows it has been interrupted if it is executing a method that will throw an InterruptedException.
Can a thread deadlock itself?
Common examples of the cause of threading deadlocks include: A thread that waits on itself (e.g. attempts to acquire the same mutex lock twice). Threads that wait on each other (e.g. A waits on B, B waits on A). Thread that fails to release a resource (e.g. mutex lock, semaphore, barrier, condition, event, etc.).
What makes a thread joinable?
A thread that has finished executing code, but has not yet been joined is still considered an active thread of execution and is therefore joinable.
What happens when a thread calls fork?
The fork( ) system call creates an exact duplicate of the address space from which it is called, resulting in two address spaces executing the same code. Problems can occur if the forking address space has multiple threads executing at the time of the fork( ).
Which exception is thrown if the caller attempted to join a thread?
Exceptions
| Exception Type | Condition |
|---|---|
| ThreadStateException | The caller attempted to join a thread that is in the System.Threading.ThreadState.Unstarted state. |
Can a detached thread be joined?
If a thread is created as detached, it can never be joined.
Why is thread stop unsafe?
stop() results in the release of all locks a thread has acquired, potentially exposing the objects protected by those locks when those objects are in an inconsistent state. The thread might catch the ThreadDeath exception and use a finally block in an attempt to repair the inconsistent object or objects.
What happens if a thread joins itself
The call returns immediately indicating an error. The call returns immediately indicating a successful completion. A thread cannot join itself – a deadlock would occur and it is detected by the library.
Can a thread call join on itself
A thread cannot join itself because a deadlock would occur and it is detected by the library. However, two threads may try to join each other. They will deadlock, but this situation is not detected by the library. The pthread_join subroutine also allows a thread to return information to another thread.
What happens if thread join is not called
If you don't join these threads, you might end up using more resources than there are concurrent tasks, making it harder to measure the load. To be clear, if you don't call join , the thread will complete at some point anyway, it won't leak or anything. But this some point is non-deterministic.
Is thread join thread safe
It is not thread safe. If you have more than one thread that can call your snippet at any time, you may experience a race condition. The only real way to protect against this is by wrapping your snippet in an std::mutex shared by the threads calling said snippet.
Can a thread interrupt itself
The interrupt() method is a method of the Thread class, and it is used by one thread to signal another thread: it is possible (although it doesn't really make sense) for a thread to interrupt itself. The target thread knows it has been interrupted if it is executing a method that will throw an InterruptedException.
Can a thread deadlock itself
Common examples of the cause of threading deadlocks include: A thread that waits on itself (e.g. attempts to acquire the same mutex lock twice). Threads that wait on each other (e.g. A waits on B, B waits on A). Thread that fails to release a resource (e.g. mutex lock, semaphore, barrier, condition, event, etc.).
What makes a thread joinable
A thread that has finished executing code, but has not yet been joined is still considered an active thread of execution and is therefore joinable.
What happens when a thread calls fork
The fork( ) system call creates an exact duplicate of the address space from which it is called, resulting in two address spaces executing the same code. Problems can occur if the forking address space has multiple threads executing at the time of the fork( ).
Which exception is thrown if the caller attempted to join a thread
Exceptions
| Exception Type | Condition |
|---|---|
| ThreadStateException | The caller attempted to join a thread that is in the System.Threading.ThreadState.Unstarted state. |
Can a detached thread be joined
If a thread is created as detached, it can never be joined.
Why is thread stop unsafe
stop() results in the release of all locks a thread has acquired, potentially exposing the objects protected by those locks when those objects are in an inconsistent state. The thread might catch the ThreadDeath exception and use a finally block in an attempt to repair the inconsistent object or objects.
How do I make thread-safe without synchronized
Lazy Creation of Singleton ThreadSafe Instance without Using Synchronized KeywordEnsure that only one instance of a class is created.Provide a global point of access to the object.Allow multiple instances in the future without affecting a singleton class's clients.
What happens when a thread wakes up another thread
What happens when a thread wakes up another thread How does a sleeping thread get to run again It removes the sleeping thread from the queue, and calls make_runnable on the thread, which currently adds it to the end of the runqueue.
What are the two ways to check if a thread has been interrupted
void interrupt() – This method is used to interrupt the thread. static boolean interrupted() – This method checks whether the current thread has been interrupted or not. boolean isInterrupted() – This method checks whether the thread has been interrupted or not.
What are the 3 causes of deadlock
The four necessary conditions for a deadlock situation to occur are mutual exclusion, hold and wait, no preemption and circular set. We can prevent a deadlock by preventing any one of these conditions. There are different ways to detect and recover a system from deadlock.
What triggers deadlock
A deadlock will occur when a transaction (A) is trying to access one or more rows which are in use by another transaction (B). Normally this is not a problem, the transaction (A) will wait until the rows are released.
Is a thread joinable by default
thread::joinable
So a default constructed thread is not joinable. A thread that has finished executing code, but has not yet been joined is still considered an active thread of execution and is therefore joinable.
Do threads have their own call stack
Distinguishing between these kinds of memory matters because each thread will have its own stack. However, all the threads in a process will share the heap. Some people call threads lightweight processes because they have their own stack but can access shared data.
What is the difference between forking and multithreading
A thread process is considered a sibling while a forked process is considered a child. Also, threads are known as light-weight processes as they don't have any overhead as compared to processes (as it doesn't issue any separate command for creating completely new virtual address space).
Is thread join a blocking call
The Thread. join() method is a blocking call. This means that it will cause the thread that calls it to stop executing until the thread it is waiting for has finished.
What exception does join () throw
InterruptedException
The join() method may also return if the referenced thread is interrupted. In this case, the method throws an InterruptedException.
Can a thread cancel itself
A thread automatically terminates when it returns from its entry-point routine. A thread can also explicitly terminate itself or terminate any other thread in the process, using a mechanism called cancelation.
Can a thread interrupt another thread
One thread can interrupt another thread by calling the second thread's interrupt method. A thread should frequently check its isInterrupted method to see if it has been interrupted. If a thread is interrupted while it is sleeping, InterruptedException is thrown.
Will thread automatically be killed
A thread automatically terminates when it returns from its entry-point routine. A thread can also explicitly terminate itself or terminate any other thread in the process, using a mechanism called cancelation.
Do threads need to be synchronized
In the Multithreading concept, multiple threads try to access the shared resources at a time to produce inconsistent results. The synchronization is necessary for reliable communication between threads.