What is a mutable method?

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On Friday, 22 May 2015 at 12:12:46 UTC, tcak wrote:
> I know there is mutable variables, but what is a mutable method?
>
> Error message says "mutable method 
> project.mariadb.connector.ver2p1.resultset.ResultSetColumn.info 
> is not callable using a const object".

The method that can change the state of the object.
This kind of error says that you try to call non-const method on 
const object, which is prohibited. You can call only the methods 
marked as const on the const object.