Question

So, I have these two functions ref() and pointy() that respectively create a local reference and pointer to a locally-defined int:

#include <iostream>

int& ref() {
  int knuckles = 6;
  int &chuckles = knuckles;
  return chuckles;
};

int* pointy() {
    int buckles = 8;
    return &buckles;
};

int main(int argc, char **argv) {
    int a = ref(), *b = pointy();
    int c = 14, d = 20;
    std::cout << a << ' ' << *b << ' ' << c+d;
};

The code compiles fine, and it gives a warning about returning the address of local variable buckles, but what concerns me is that it doesn’t say anything about ref() returning a reference to knuckles.
Is my compiler (g++ via MinGW, if it makes a difference) just sleeping on the job? Is there something about references that keeps the referent from going out of scope? Or is my reference syntax just bad?

Much obliged!

Answer 1

Your two test cases aren’t parallel. This program:

#include <iostream>

int& ref() {
  int knuckles = 6;
  return knuckles;
};

int* pointy() {
    int buckles = 8;
    return &buckles;
};

int main(int argc, char **argv) {
    int a = ref(), *b = pointy();
    int c = 14, d = 20;
    std::cout << a << ' ' << *b << ' ' << c+d;
};

Produces these warnings:

$ g++ -O4 -std=c++0x    x.cc   -o x
x.cc: In function ‘int& ref()’:
x.cc:4:7: warning: reference to local variable ‘knuckles’ returned [enabled by default]
x.cc: In function ‘int* pointy()’:
x.cc:9:9: warning: address of local variable ‘buckles’ returned [enabled by default]