Creational Design Patterns in Modern C++ - Multithreading Issues

The video tutorial explores the challenges of using a logger in a multithreaded application. It begins by demonstrating the problem of multiple logger instances being created when two threads call the instance method simultaneously. The solution involves using a mutex to ensure thread safety, making the logger class suitable for multithreaded applications. However, the video also highlights the performance drawbacks of this approach and introduces the double checked locking pattern to mitigate these issues. Finally, it warns about potential pitfalls of the double checked locking pattern, such as non-atomic operations leading to invalid values.

How can the performance of an application be negatively impacted by locking after the instance is created?

What potential problem arises when one thread modifies an instance variable while another thread reads from it?

What happens if a thread reads an invalid value from an instance variable?