pthread_attr_t definition is incorrect, will cause unaligned memory accesses

[thestinger]

It's not correct to bind a union in Rust as an array of bytes. The alignment of a byte array is always 1.

struct Foo {
    xs: [u8, ..64]
}

fn main() {
    println!("{}", std::mem::min_align_of::<Foo>())
}

x86 allows unaligned memory accesses, but other architectures are not as forgiving.

[thestinger]

This was implemented by 47e0bd4, but I don't think it's possible to correctly express this in Rust until we have either a way to specify minimum alignment or a direct analogy to union.

[thestinger]

cc @alexcrichton

[alexcrichton]

Hm, it is kinda nice having these defined in rust instead of having to malloc them. Do you know if we change the to all just [u64, ..N] if things would be ok? Or would this want some sort of #[align] attribute?

[thestinger]

Building them out of a combination of u64 and u32 would work.