Struct FlowHandle 

pub struct FlowHandle { /* private fields */ }

A reference to a spawned flow, returned by super::runtime::Runtime::spawn.

Holding a FlowHandle does not keep the flow alive — it is a way to (a) read its FlowId for addressing with Send, and (b) block the calling native thread until it finishes via FlowHandle::join. Dropping without joining is fine (fire-and-forget).

Implementations

impl FlowHandle

pub fn id(&self) -> FlowId

pub fn join(self) -> FlowOutcome

Block the current (native) thread until the flow terminates. Never call from inside a worker / from bytecode.

Examples found in repository

examples/ping_pong.rs (line 36)

fn main() {
    let chunk = samples::ping_pong();
    let rt = match Runtime::with_natives_and_config(
        chunk,
        std_native_table(),
        RuntimeConfig {
            workers: 1,
            quantum: 10_000,
        },
    ) {
        Ok(rt) => rt,
        Err(e) => {
            eprintln!("runtime: {e}");
            std::process::exit(1);
        }
    };
    let Some(main) = rt.function_index("main") else {
        eprintln!("missing main");
        std::process::exit(1);
    };
    let handle = match rt.spawn(main, &[]) {
        Ok(h) => h,
        Err(e) => {
            eprintln!("spawn: {e}");
            std::process::exit(1);
        }
    };
    let outcome = handle.join();
    let metrics = rt.metrics();
    rt.shutdown();

    match outcome {
        FlowOutcome::Completed(Value::Int(2)) => {
            println!("pong replied 2 (Atomic Hop)");
            println!("{metrics}");
        }
        other => {
            eprintln!("unexpected {other:?}");
            std::process::exit(1);
        }
    }
}

examples/atomic_actors.rs (line 48)

fn main() {
    let chunk = samples::atomic_request_reply();
    let rt = match Runtime::with_natives_and_config(
        chunk,
        std_native_table(),
        RuntimeConfig {
            workers: 2,
            quantum: 10_000,
        },
    ) {
        Ok(rt) => rt,
        Err(e) => {
            eprintln!("runtime: {e}");
            std::process::exit(1);
        }
    };
    let Some(main) = rt.function_index("main") else {
        eprintln!("missing main");
        std::process::exit(1);
    };
    let handle = match rt.spawn(main, &[]) {
        Ok(h) => h,
        Err(e) => {
            eprintln!("spawn: {e}");
            std::process::exit(1);
        }
    };
    let outcome = handle.join();
    let metrics = rt.metrics();
    rt.shutdown();

    match outcome {
        FlowOutcome::Completed(Value::Int(42)) => {
            println!("atomic request-reply ok: payload=42");
            println!("{metrics}");
        }
        other => {
            eprintln!("unexpected {other:?}");
            std::process::exit(1);
        }
    }
}

examples/throughput.rs (line 60)

fn main() {
    let n: u32 = std::env::args()
        .nth(1)
        .and_then(|s| s.parse().ok())
        .unwrap_or(50_000);

    let workers = std::thread::available_parallelism()
        .map(|p| p.get())
        .unwrap_or(1);

    let rt = match Runtime::with_config(
        trivial_chunk(),
        RuntimeConfig {
            workers,
            quantum: 10_000,
        },
    ) {
        Ok(rt) => rt,
        Err(e) => {
            eprintln!("runtime: {e}");
            std::process::exit(1);
        }
    };
    let Some(worker_fn) = rt.function_index("worker") else {
        eprintln!("missing worker");
        std::process::exit(1);
    };

    let start = Instant::now();
    let mut handles = Vec::with_capacity(n as usize);
    for _ in 0..n {
        match rt.spawn(worker_fn, &[]) {
            Ok(h) => handles.push(h),
            Err(e) => {
                eprintln!("spawn: {e}");
                std::process::exit(1);
            }
        }
    }
    let mut ok = 0u32;
    for h in handles {
        if matches!(h.join(), FlowOutcome::Completed(Value::Int(1))) {
            ok += 1;
        }
    }
    let elapsed = start.elapsed();
    let metrics = rt.metrics();
    rt.shutdown();

    let secs = elapsed.as_secs_f64().max(1e-9);
    println!("processes={ok}/{n}");
    println!("workers={workers}");
    println!("elapsed_ms={:.2}", elapsed.as_secs_f64() * 1000.0);
    println!("spawns_per_sec={:.0}", ok as f64 / secs);
    println!("{metrics}");
}