using const with function

[oj2wbRfi]

what is the purpose of using const with function

  void readData () {}
  void readData const () {}

[George P]

https://stackoverflow.com/questions/751681/meaning-of-const-last-in-a-function-declaration-of-a-class

[seeplus]

For that case, the const goes after the () and the function has to be a class member function. In the above, the const is before the () !

@Ivanka - is this a misprint as that is invalid syntax?

[Peter87]

It is a promise that the function will not modify the object that it's called on.

obj.readData(); // will not modify obj 

It's similar to marking reference parameters as const.

void foo(const T&);

foo(obj); // will not modify obj