Macro kernel::stack_try_pin_init

macro_rules! stack_try_pin_init {
    (let $var:ident $(: $t:ty)? = $val:expr) => { ... };
    (let $var:ident $(: $t:ty)? =? $val:expr) => { ... };
}

Initialize and pin a type directly on the stack.

Examples

#[pin_data]
struct Foo {
    #[pin]
    a: Mutex<usize>,
    b: Box<Bar>,
}

struct Bar {
    x: u32,
}

stack_try_pin_init!(let foo: Result<Pin<&mut Foo>, AllocError> = pin_init!(Foo {
    a <- new_mutex!(42),
    b: Box::new(Bar {
        x: 64,
    }, GFP_KERNEL)?,
}));
let foo = foo.unwrap();
pr_info!("a: {}", &*foo.a.lock());

#[pin_data]
struct Foo {
    #[pin]
    a: Mutex<usize>,
    b: Box<Bar>,
}

struct Bar {
    x: u32,
}

stack_try_pin_init!(let foo: Pin<&mut Foo> =? pin_init!(Foo {
    a <- new_mutex!(42),
    b: Box::new(Bar {
        x: 64,
    }, GFP_KERNEL)?,
}));
pr_info!("a: {}", &*foo.a.lock());

Syntax

A normal let binding with optional type annotation. The expression is expected to implement PinInit/Init. This macro assigns a result to the given variable, adding a ? after the = will propagate this error.