Where all to use volatile keyword in C

Question

I know volatile keyword prevents compiler from optimizing a variable and read it from memory whenever it is read. Apart from memory mapped registers, what are all the situat

Answer 1

Besides extensions such as memory mapped devices, in standard C volatile has two use cases: interaction with signal handlers and modification of objects across usage of setjmp/longjmp. Both are case were there is unusual flow of control that an optimizer may not be aware of.