Question

Can I have functors in C? I mean for example in C++ I can do:

struct Rules
{

    operator()(/*maybe some args*/)
    {
    }
};

Some (fictitious) algorithm:

int sort(iter beg, iter end, Rules);

Can I do identically in C?

Answer 1

Not really. At best, you could do something like:

int sort(iter a, iter b, bool (*cmp)(iter a, iter b, void *), void *p_state)
{
    ...
    cmp(a, b, p_state);
}


bool func(iter a, iter b, void *p_state)
{
    type_t *p_type = (type_t *)p_state;
    ...
}


type_t state;
...
sort(a, b, func, &state);

This allows you to give the function state, albeit manually.

You may be able to hide some of the clunkiness behind macros, but beware macros!