The static Atomics
.wake()
method wakes up some agents that are sleeping in the wait queue.
Note: This operation works with a shared Int32Array
only.
Syntax
Atomics.wake(typedArray, index, count)
Parameters
typedArray
- A shared
Int32Array
. index
- The position in the
typedArray
to wake up on. count
- The number of sleeping agents to wake. Defaults to
+Infinity
.
Return value
A number of woken up agents.
Exceptions
- Throws a
TypeError
, iftypedArray
is not a sharedInt32Array
. - Throws a
RangeError
, ifindex
is out of bounds in thetypedArray
.
Examples
Given a shared Int32Array
:
var sab = new SharedArrayBuffer(1024); var int32 = new Int32Array(sab);
A reading thread is sleeping and waiting on location 0 which is expected to be 0. As long as that is true, it will not go on. However, once the writing thread has stored a new value, it will be woken up by the writing thread and return the new value (123).
Atomics.wait(int32, 0, 0); console.log(int32[0]); // 123
A writing thread stores a new value and wakes up the waiting thread once it has written:
console.log(int32[0]); // 0; Atomics.store(int32, 0, 123); Atomics.wake(int32, 0, 1);
Specifications
Specification | Status | Comment |
---|---|---|
ECMAScript Latest Draft (ECMA-262) The definition of 'Atomics.wake' in that specification. |
Living Standard | Initial definition in ES2017. |
Browser compatibility
Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|---|
Basic support | 601 | 16 | 55 | No | No | 10.1 |
Feature | Android webview | Chrome for Android | Edge mobile | Firefox for Android | IE mobile | Opera Android | iOS Safari |
---|---|---|---|---|---|---|---|
Basic support | 60 | 60 | ? | 55 | No | No | No |
1. The count
parameter defaults to 0
, instead of +Infinity
.
2. In versions 46 and 47, this method was named Atomics.futexWake()
and the count
parameter defaulted to 0
.
3. From version 46 until version 54 (exclusive): this feature is behind the javascript.options.shared_memory
preference (needs to be set to true
). To change preferences in Firefox, visit about:config.