Errors

Every fallible call answers ucall::Result, whose Error carries the Status the library reported and a static message beside it, so nothing allocates on the failure path. A mistake the binding catches before calling the library, like polling an event loop the server lacks, reports the status the library would have used. Status prints its stable spelling, such as “connection-failed”, and a status a newer library added reads as Status::Internal.

use ucall::*;

let mut client = Client::new(ClientOptions { connections: 1, ..Default::default() })?;
match client.get("http://127.0.0.1:1/") {
    Ok(response) => println!("answered {}", response.status_code().0),
    Err(error) if error.status == Status::ConnectionFailed => println!("nobody listens: {error}"),
    Err(error) => return Err(error.into()),
}

A submitted call that fails completes with Err in Completed::response: Status::ConnectionFailed, Status::ConnectionClosed, Status::Timeout, Status::HandshakeFailed or Status::PeerRejected. A request lookup that finds nothing answers None, and HTTP error statuses are ordinary responses. Backend and CPUClass print and parse their stable names, like “linux-uring618” and “intel-icelake”, failing with Status::InvalidArgument on a name no value has, and Status::from_name reads a status back from its spelling. ucall::version() spells the linked library’s version, candidate suffix included. ucall::decode_percent decodes a path or a query value, which requests lend still percent-encoded.