Bits of .NET

🧵 Multiple Threads, One Memory

Web Workers communicate via message passing. SharedArrayBuffer + Atomics enables shared memory. No copying. True multithreading.

📝 Basic Shared Memory

// Main thread
const sharedBuffer = new SharedArrayBuffer(Int32Array.BYTES_PER_ELEMENT * 2);
const sharedArray = new Int32Array(sharedBuffer);
sharedArray[0] = 0;  // Counter

const worker = new Worker('worker.js');
worker.postMessage(sharedBuffer);  // Transfer, not copy!

// worker.js
let sharedArray;
self.onmessage = (e) => {
  sharedArray = new Int32Array(e.data);
  
  // Atomic increment
  Atomics.add(sharedArray, 0, 1);
  
  // Notify main thread
  Atomics.notify(sharedArray, 0, 1);
};

// Main thread waiting
Atomics.wait(sharedArray, 0, 0);  // Wait until value changes

✅ Atomics Methods

// Atomic operations (no race conditions)
Atomics.add(array, index, value)      // atomic addition
Atomics.sub(array, index, value)      // atomic subtraction
Atomics.and(array, index, value)      // atomic AND
Atomics.or(array, index, value)       // atomic OR
Atomics.xor(array, index, value)      // atomic XOR
Atomics.compareExchange(array, index, expected, replacement)
Atomics.exchange(array, index, value)

// Synchronization
Atomics.wait(array, index, value)     // Wait until value changes
Atomics.notify(array, index, count)   // Wake waiting threads

// Loading/storing (ensures ordering)
Atomics.load(array, index)
Atomics.store(array, index, value)