In C/C++, " volatile " is needed when developing embedded systems or device drivers, where you need to read or write a memory-mapped hardware device. The contents of a particular device register could change at any time, so you need the " volatile " keyword to ensure that such accesses aren't optimized away by the compiler. Volatile Variables In C++ the volatile keyword is used to declare a variable whose value can be changed by various external factors that are outside the program's control, such as hardware or a concurrently executing thread. This prevents the compiler from doing some optimizations assuming the variable value remains unchanged unless explicitly changed within the program. Following is the syntax to use the volatile keyword in C++. Syntax to Define Volatile Variable volatile type variable_Name ... Watch out when a situation becomes volatile — it is likely to change for the worse suddenly. If you and your best friend have a volatile relationship, you frequently fight and make up. What Does " Volatile " Really Mean? — A Deep Dive The word “ volatile ” is a fascinating term packed with layers of meaning. It’s often used to describe something that’s changeable, unpredictable, or unstable. But, as with many words, its exact connotation depends on the context. Definition of " Volatile " Let’s break down the core meanings of " volatile " using a simple definition list:
