What is the difference between thread safety and thread-local storage in C++?

What is the difference between thread safety and thread-local storage in C++?

Thread safety refers to the property of a piece of code to function correctly during simultaneous execution by multiple threads. In contrast, thread-local storage allows each thread to have its own instance of a variable, preventing interference between threads.

Can you give an example of thread-local storage in C++?

Sure! You can use the thread_local keyword in C++. For example:

thread_local int counter = 0;
void incrementCounter() {
    counter++;
}
``` This ensures that each thread has its own `counter` variable.

When should I use thread-local storage instead of making a function thread-safe?

Use thread-local storage when you need each thread to maintain its own state without sharing it. If you need to share data safely across threads, then you should implement thread safety mechanisms like mutexes.

Are there any performance implications of using thread-local storage?

Yes, thread-local storage can improve performance by reducing contention between threads, but it may increase memory usage since each thread has its own copy of the variable.