Trying to pass adress to a reffernce to a pointer

Question

Why calling funk(&a) gives a compile error

func(int * & data) {data++;}

int main(){

int a = 5;
int *p = &a;
func(&a); //this gives a compile error
funk(p);  //this works fine 
}

error: invalid initialization of non-const reference of type ‘int*&’ from an rvalue of type ‘int*’

because `a` is of type constant (address can't be changed). you can't change `a` address(which you are doing inside the function). — roottraveller, Jan 25 '16 at 03:55
You cannot modify an _rvalue_. That is what `func(&a)` is attempting. When you pass a reference, it must be either an _lvalue_ or have a _const-qualifier_. — paddy, Jan 25 '16 at 03:55
@paddy actually rvalues can be modified. Example `std::string().resize(5);` . This code is illegal because it attempts to bind an lvalue reference to an rvalue. — M.M, Jan 25 '16 at 05:30

score 2 · Accepted Answer · answered Jan 25 '16 at 03:58

2

Just as the error message explains, the parameter needs to reference a variable, and &a is not a variable, it's an address of a variable.

answered Jan 25 '16 at 03:58

Amit

1 Answers1