Macro ctor

macro_rules! ctor {
    (
        $(#[$meta:meta])*
        $vis:vis unsafe fn $name:ident () $bl:block
    ) => { ... };
    (
        $(#[$meta:meta])*
        $vis:vis unsafe static $(mut)? $name:ident:$ty:ty = $e:expr;
    ) => { ... };
}

Run a function on program startup or initialize a constant.

See the crate level documentation for more info.