Struct CWakeState 

#[repr(C)]
pub struct CWakeState {
    pub fn_ptr: Option<CWakeFn>,
    pub ctx: *mut c_void,
}

Stable-address storage for a C wake callback. The pointer to this struct is what the Waker holds in its RawWaker::data slot, so it MUST NOT move after a Waker has been built from it.

Fields

fn_ptr: Option<CWakeFn>

Function called when the Waker is woken. None disables.

ctx: *mut c_void

Opaque pointer passed to fn_ptr on wake.

Implementations

impl CWakeState

pub const fn empty() -> Self

Empty / disabled state.

pub fn set(&mut self, fn_ptr: Option<CWakeFn>, ctx: *mut c_void)

Update the callback. Existing Wakers built from self pick up the new value on their next wake — no re-registration needed (the Waker’s data pointer is unchanged).

Trait Implementations

impl Send for CWakeState

SAFETY: CWakeState holds a function pointer (Send/Sync) + an opaque user ctx pointer (no auto-impl). For the wake path to be sound across threads the C caller must ensure the underlying object behind ctx is reachable from whatever thread the backend dispatches the wake callback on. By marking the state as Send+Sync we let backends (e.g. AtomicWaker) stash the Waker in shared state; the C contract is documented at the FFI surface (“the C ctx must outlive every wake-callback invocation and be safe to read from any thread the runtime dispatches wakes on”).

impl Sync for CWakeState