CPP Concurrency & Multithreading

Question 1

What is a race condition in concurrent programming?

Accepted Answer

A bug where program outcome depends on the relative timing of thread execution

Answer

Two threads competing to be scheduled first at startup

Answer

A deadlock involving more than two threads

Answer

A thread running faster than the scheduler allows

Question 2

What is a mutex (mutual exclusion lock)?

Accepted Answer

A synchronization primitive that allows only one thread at a time to access a critical section

Answer

A mechanism that allows all threads to read shared data simultaneously

Answer

A thread scheduling algorithm

Answer

A lock-free data structure

Question 3

What is a deadlock in multithreaded programs?

Accepted Answer

A state where two or more threads each wait forever for resources held by the others

Answer

A thread that is executing too slowly

Answer

A thread that never releases the CPU

Answer

An exception thrown inside a thread

Question 4

What is the difference between parallelism and concurrency?

Accepted Answer

Concurrency is about dealing with multiple tasks at once (possibly interleaved); parallelism is executing multiple tasks simultaneously on multiple processors

Answer

They are identical concepts

Answer

Parallelism is single-threaded; concurrency is multi-threaded

Answer

Concurrency requires multiple CPUs; parallelism does not

Question 5

What is a thread-safe data structure?

Accepted Answer

A data structure that correctly handles simultaneous access from multiple threads without data corruption

Answer

A data structure that can only be used by one thread

Answer

A data structure stored in thread-local storage

Answer

A data structure that uses no locks

Question 6

What is a semaphore in concurrent programming?

Accepted Answer

A signaling mechanism that controls access to a limited number of resources using a counter

Answer

A type of thread pool

Answer

A way to terminate threads gracefully

Answer

A hardware interrupt handler