What is extern volatile in C?

Related questions

1. What are atomic operations?
2. What is difference between static and volatile in C?
3. What is an atomic update?
4. What is atomic in multithreading?
5. What is a runnable?
6. What is callable and future?
7. Is runnable marker interface?
8. Is mutex lock Atomic?
9. What is an atomic process?
10. What are atomic instructions?

Tags

1. #somewhere
2. #consistent
3. #outside
4. #external
5. #defined
6. #variable
7. #extern
8. #should
9. #example
10. #scope
11. #could
12. #world
13. #modification
14. #means
15. #header
16. #definition
17. #volatile