I'm having a problem with a project that was originally a C project and is being extended with C . E.g. all the APIs are C, and the application layer is C . It mostly works, except I seem to be unable to define constructors that do any sort of processing in pre-main. It's like the memory exists, and the reference is valid, but the constructor itself just doesn't execute. Running -Wall and -Wextra, the only error I get is that I'm missing a memory region definition for .ctors.

I did notice that the linker flags include -nostartfiles, so I tried disabling that flag but I ended up with some additional memory region warnings about the size of .ctors and .dtors changing and an undefined reference to main, which I thought was... odd.

So, any idea where I would start investigating the bug? I'm thinking maybe GCC is putting constructors in __main but the linker script is pointing the start of the program to something other than main()?

SSCCE below:

#include <iostream>
using namespace std;

class Foo {
    public:
        Foo() {
            bar_ = 10;
        };

        Foo(int bar) : bar_(bar) {};

        void setBar(int val) {
            bar_ = val;
        }

        int getBar() {
            return bar_;
        }

    private:
        int bar_;
};


Foo myObj;
Foo otherObj(10);

int main(){
    // Default Constructor
    cout << myObj.getBar() << endl;     // Prints 0
    myObj.setBar(10);
    cout << myObj.getBar() << endl;     // Prints 10

    // Parameterized constructor
    cout << otherObj.getBar() << endl;  // Prints 0
    otherObj.setBar(10);
    cout << otherObj.getBar() << endl;  // Prints 10

    // Parameterized constructor (local)
    Foo thirdObj(10);
    cout << thirdObj.getBar() << endl;  // Prints 10
}