Derive Macro ServiceSpecificError 

#[derive(ServiceSpecificError)]

Binder service-specific error codes for a plain Rust enum.

Implements rsbinder::ServiceSpecificError, so the type can be passed to Status::service_specific and read back with Status::service_error::<T>() instead of a bare i32.

#[derive(ServiceSpecificError, Clone, Copy, PartialEq, Eq, Debug)]
#[repr(i32)]
pub enum LookupError { NotFound = 1, Busy = 2 }

Err(Status::service_specific(LookupError::Busy, Some("try again")))

#[repr(i8)], #[repr(i16)] or #[repr(i32)] is required, and every variant needs an explicit value — it is the number a peer matches on, so it belongs at the declaration rather than in declaration order. A wider repr is refused here rather than truncated on the wire, where a binder status carries the code as an i32.

This derive does not touch the parcel: an error code travels in the status header, not as a value in the payload. Combine it with #[derive(BinderEnum)] when the same enum is also a method argument or return value.

For an .aidl enum, use rsbinder::impl_service_specific_error! instead — the generated type is an open newtype, not a Rust enum, so a derive cannot be attached to it. Never both on one type: two impls of one trait do not compile.