//---- exploring FFI: how to pass in a struct and have it modified?
int write_test(int start, int count, char* buf) {
    int i=0;
    for(i=0; i<count; i++) {
        *(buf+i) = 0x41+i; // A, B, C...
    }
    return 42;
}
   './mylib.dylib write_test i i i *' cd 0;10;(10#' ')
┌──┬─┬──┬──────────┐
│42│0│10│ABCDEFGHIJ│
└──┴─┴──┴──────────┘