Volatile Member Functions. McGraw-Hill The Complete Reference Fourth Edition

C h a p t e r 2 3 : N a m e s p a c e s , C o n v e r s i o n F u n c t i o n s , a n d O t h e r A d v a n c e d T o p i c s

609 mutable int i; int j; public: int geti() const { return i; // ok

} void seti(int x) const { i = x; // now, OK.

}

/* The following function won't compile.

void setj(int x) const { j = x; // Still Wrong!

*/

}

}; int main()

{

Demo ob; ob.seti(1900); cout << ob.geti();

} return 0;

Here, i is specified as mutable, so it may be changed by the seti( ) function. However,

j

is not mutable and setj( ) is unable to modify its value.

Volatile Member Functions

Class member functions may be declared as volatile, which causes this to be treated as a volatile pointer. To specify a member function as volatile, use the form shown in the following example: class X { public:

}; void f2(int a) volatile; // volatile member function