Array alignment

[daurnimator]

As part of my module's public members, I want to expose a type that is an array of u8 with align(4).
This currently fails with

error: align qualifier invalid on array type
pub const State = [48]align(4)u8;

[andrewrk]

The syntax is

pub const state align(4) = [48]u8{...}

Or

pub const state: [48]u8 align(4) = undefined

The alignment is a property of the variable (memory location), not the type.

[daurnimator]

e.g. I have a function:

pub const State = [48]u8;
pub fn foo(state: *align(4)State) void {

And I want a user to be able to write:

fn bar() {
    var state: State = StateInitializer;
    foo(&state);
}

Then they get an alignment error.

How can they fix it?

[andrewrk]

They would have to put the alignment on the state variable like this:

    var state: State align(4) = StateInitializer;

If you want to encapsulate this into a type you'll need to use a struct and this issue needs to be implemented: #1512

[daurnimator]

If you want to encapsulate this into a type you'll need to use a struct and this issue needs to be implemented: #1512

Thanks. I'm working around it for now by lying about the type (saying it's a const State = [48 / 4]u32; instead) and using @sliceToBytes everywhere.