| volatile | Keyword

Keyword Index

Indicates that a variable can be changed by a background routine.

Keyword `volatile` is an extreme opposite of `const`. It indicates that a variable may be changed in a way which is absolutely unpredictable by analysing the normal program flow (for example, a variable which may be changed by an interrupt handler). This keyword uses the following syntax:

    volatile data-definition;

Every reference to the variable will reload the contents from memory rather than take advantage of situations where a copy can be in a register.