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21 Type Qualifiers

A declaration can include type qualifiers to advise the compiler about how the variable will be used. There are three different qualifiers, const, volatile and restrict. They pertain to different issues, so you can use more than one together. For instance, const volatile describes a value that the program is not allowed to change, but might have a different value each time the program examines it. (This might perhaps be a special hardware register, or part of shared memory.)

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