#include <stdlib.h>
#include <string.h>
#include <stdio.h>

struct Foo
{
    int a;
    int b;
};

void Foo_set(struct Foo *f, int a, int b)
{
    f->a = a;
    f->b = b;
}

int main()
{
    struct Foo *f = malloc(sizeof(struct Foo));
    memset(f, 0, sizeof(struct Foo));

    Foo_set(f, 1, 2);

    printf("%i, %i\n", f->a, f->b);

    free(f);

    return 0;
}