What causes std::bad_function_call?

Question

I\'ve seen a few questions that refer to the std::bad_function_call exception, but haven\'t been able to find out any by Googling about what causes this exception.

W

Answer 1

Call of a temporary function also can throw:

struct F
{
    const std::function<void()>& myF;

    F(const std::function<void()>& f) : myF(f) {}

    void call()
    {
        myF();
    }
};

int main()
{
    F f([]{ std::cout << "Hello World!" << std::endl;});

    f.call();

    return 0;
}

But this depend on compiler (vc++ throws, g++ not).

Answer 2

in my case was the problem was in capture list. i have a recursive lambda function.

//decl
std::function<void(const SBone*, const core::vector3df&, const core::quaternion&)> f_build;
f_build = [&f_build](const SBone* bone, const core::vector3df& pos, const core::quaternion& rot)
{
...
}

missing & from f_build in capture list generate a bad call.

Answer 3

Sure- the easiest is where you try to call a std::function that's empty.

int main() {
    std::function<int()> intfunc;
    int x = intfunc(); // BAD
}

Answer 4

"Performing a function call without having a target to call throws an exception of type std::bad_function_call"

    std::function<void(int,int)> f;
    f(33,66); // throws std::bad_function_call

No credits to me....its Nicolai Josuttis Pundit of C++ Standard Lib