A Quiz in Advanced RE (Asm/C)

[zeffy]

Originally Posted by chants

3) as far as I know its the captures that are on the temporary object, and the actual function arguments are passed per __thiscall logic.

Oops, you're right. I knew that but mixed up the terminology (captures vs arguments), heh.

Here's an example of how MSVC seems to implement lambdas:

bool normal_function()
{
    int a, b, c;
    int d = 0;
    int e = 0;
    int f = 0;

    return [a, b, c](int, int, int) -> bool {
        return true;
    }(d, e, f);
}

Which is compiled into something resembling this:

bool normal_function()
{
    class lambda_class
    {
        int *a_;
        int *b_;
        int *c_;

    public:
        lambda_class(int *a, int *b, int *c)
            : a_(a), b_(c), c_(c)
        {
        }

        bool operator()(int d, int e, int f)
        {
            return true;
        }
    };

    int a, b, c;
    int d = 0;
    int e = 0;
    int f = 0;

    return lambda_class(&a, &b, &c)(d, e, f);
}