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Programming-Idioms

# 25 Send a value to another thread
Share the string value "Alan" with an existing running process which will then display "Hello, Alan"
New implementation

Be concise.

Be useful.

All contributions dictatorially edited by webmasters to match personal tastes.

Please do not paste any copyright violating material.

Please try to avoid dependencies to third-party libraries and frameworks.

Other implementations 
declare

   task Greeter is
      entry Greet (Name : String);
   end Greeter;

   task body Greeter is
   begin

      accept Greet (Name : String) do
         Ada.Text_IO.Put_Line ("Hello, " & Name);
      end Greet;

   end Greeter;

begin
   Greeter.Greet ("Alan");
end;
(require '[clojure.core.async :refer :all])
(def c (chan 1))

(go (println "Hello," (<! c)))

(>!! c "Alan")
#include <future>
#include <mutex>
#include <iostream>
#include <optional>
#include <condition_variable>
//declaration
auto mutex = std::mutex{};
auto cv = std::condition_variable{};
auto variable = std::optional<std::string>{};
auto future = std::async([&]() {
	auto lock = std::unique_lock{mutex, std::defer_lock};
	cv.wait(lock, [&variable](){ return variable.has_value(); });
	std::cout << "Hello, " << *variable << "!" << std::endl;
});

//passing value in main thread (or it can be done in others as well)
{
	auto lock = std::unique_lock{mutex};
	variable = "Alan";
	cv.notify_all();
}
using System.Threading;
using(var readyEvent = new ManualResetEvent(false))
{
    var thread = new Thread(() =>
    {
        readyEvent.WaitOne();
        Console.WriteLine(value);
    });

    thread.Start();

    value = "Alan";
    readyEvent.Set();

    thread.Join();
}
using System.Collections.Concurrent;
using System.Threading;
ConcurrentQueue<int> coll = new ConcurrentQueue<int>();
var ts = new CancellationTokenSource();
CancellationToken ct = ts.Token;

Task t2 = Task.Factory.StartNew(() => {
	while (true) {
		Thread.Sleep(250);
		if (ct.IsCancellationRequested) break;
			bool isDequeued = coll.TryDequeue(out int result);
			if (isDequeued) Console.WriteLine(result);
	}});
while (true) {
	int val = Convert.ToInt32(Console.ReadLine());
	if (val == -1) break;
	coll.Enqueue(val);
}
ts.Cancel();
import std.concurrency;
import std.stdio;
auto t = spawn( {
   receive( (string s) { writefln("Hello, %s", s); } );
} );

t.send("Alan");
import "dart:isolate";
sendPort.send("value");
pid = spawn fn ->
  receive do
    {:hello, name} ->
      IO.puts("Hello, #{name}")
    _ ->
      IO.puts(:stderr, "Unexpected message received")
  end
end

send pid, {:hello, "Alan"}
str[1] = "Alan"
sync all
if (this_image() == 1) then
  print *,"Hello, ", str
end if
import "fmt"
go func() {
	v := <-ch
	fmt.Printf("Hello, %v\n", v)
}()

ch <- "Alan"
import Control.Concurrent.Chan
peopleToGreet <- newChan
writeChan peopleToGreet "Alan"

{
  // in file worker.js
  onmessage = ({data}) => {
    console.log (`Hello, ${data}`)
  }
}
{
  // in file main.js
  const worker = new Worker ('worker.js')
  worker.postMessage ('Alan')
}
import { isMainThread, Worker, parentPort } from 'worker_threads';
if (isMainThread) {
  const worker = new Worker(new URL(import.meta.url));
  worker.postMessage('Alan');
} else {
  parentPort.once('message', (message) => {
    console.log(`Hello, ${message}`);
  });
}
https://gist.github.com/f7c174c53efaba4d8575
import static java.lang.System.out;
import static java.lang.Thread.sleep;
class Process {
    volatile String s;
    void f() throws InterruptedException {
        Thread a = new Thread(() -> {
            try {
                sleep(1_000);
                out.println("Hello, " + s);
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
        });
        a.start();
        sleep(500);
        s = "Alan";
    }
}
Process p = new Process();
p.f();
extension=pthreads.so

class AsyncOperation extends Thread
{
    private $name;

    public function __construct($arg)
    {
        $this->name = $arg;
    }

    public function run()
    {
        sleep(1);
        if ($this->name) {
            printf("Hello %s\n", $this->name);
        }
    }
}

$thread = new AsyncOperation("World");

if ($thread->start()) {
    $thread->merge(['name' => 'Alan']);
}
Uses IdThreadSafe; // From Indy
var Queue: TIdThreadSafeStringList;

type

TTask = class(TThread)
  procedure Execute; override;
end;

procedure TTask.Execute;
begin
  while not Terminated do begin
    Sleep(10);
    with Queue.Lock do try
      while Count > 0 do begin
        WriteLn('Hello, ', Strings[0]);
        Delete(0);
      end;
    finally
      Queue.Unlock;
    end;
  end;
end;

begin
  Queue := TIdThreadSafeStringList.Create;
  TTask.Create(False);
  Queue.Add('Alan');
  Sleep(5000);
end. 

use threads;
use threads::shared;
my @queue :shared;

threads->create('my_task');
push @queue, 'Alan';
sleep 5;

sub my_task {
   while (1) {
      while (@queue) {
         print "Hello, ", (pop @queue), "\n";
      }
      sleep 1;
}

         
      
from queue import Queue
from threading import Thread
q = Queue()

def worker():
    while True:
        print(f"Hello, {q.get()}")
        q.task_done()

Thread(target=worker, daemon=True).start()

q.put("Alan")
q.join()
queue = Queue.new
thread = Thread.new do
  puts queue.pop
end
queue << "Alan"
thread.join

use std::thread;
use std::sync::mpsc::channel;
let (send, recv) = channel();

thread::spawn(move || {
    loop {
        let msg = recv.recv().unwrap();
        println!("Hello, {:?}", msg);
    }  
});

send.send("Alan").unwrap();

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