[FIXED] How can I make GCC/Clang warn about the use of uninitialized members?

Issue

I am compiling the code behind

class Test {
public:
    Test() {}

    int k;
};

int main() {
  Test t;
  std::cout << t.k << "\n";
}

like

g/clang++ main.cpp -Wall -Wextra --std=c++14 -o exe; ./exe

Why neither of the compilers does not warn me about indeterminate value of the integer is not it a very serious potential bug? How to enable a warning for indeterminate initializations?

Solution

For this example, GCC gives me the desired warning when I give it -O1 (or higher).

Presumably whatever mechanism it uses to detect this is tied into the optimisation effort level somehow. It's a notoriously hard thing to do.

Ensure that you heed your release-build warnings as well as debug-build warnings.

Answered By - Lightness Races in Orbit

Answer Checked By - Timothy Miller (PHPFixing Admin)