Julia - fixed size array in C struct

Question

I need to make a Julia type corresponding to a C struct that has a fixed size array:

struct cstruct {
    ...
    int arr[N] //N known at compile time
    ...
};

I have defined Julia types corresponding to other C structs with arrays like this:

type  jstruct
    ...
    arr::Ptr{Cint}
    ...
end

But as I understand it, this only works when arr is a pointer, not an array of a specific size. How can I ensure that the offsets of elements coming after arr remain the same in both languages?

Answer 1

When you define a C struct with a fixed size array (or with the array hack), the data are stored directly inline within that struct. It's not a pointer to another region. The equivalent Julia structure is:

type JStruct{N}
    arr::NTuple{N,Int}
end

That will store the integers directly inline within the struct.