Atomics.notify
The static Atomics
.notify()
method notifies up some agents that are sleeping in the wait queue.
Note: This operation works with a shared Int32Array
only.
Syntax
Atomics.notify(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 notify. Defaults to
+Infinity
.
Return value
A number of woken up agents.
Exceptions
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 notified 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 notifies the waiting thread once it has written:
console.log(int32[0]); // 0;
Atomics.store(int32, 0, 123);
Atomics.notify(int32, 0, 1);
Specifications
|
Desktop |
|
Chrome |
Edge |
Firefox |
Internet Explorer |
Opera |
Safari |
Basic support |
68
- 68
- 60 — 63
- Chrome disabled
SharedArrayBuffer on January 5, 2018 to help reduce the efficacy of speculative side-channel attacks. This was a temporary removal while mitigations were put in place.
- Uses the non-standard name:
wake
|
16
- 16
- Support was removed to mitigate speculative execution side-channel attacks (Windows blog).
- Uses the non-standard name:
wake
|
63 Disabled
- 63
Disabled
- Support was disabled by default to mitigate speculative execution side-channel attacks (Mozilla Security Blog).
- Disabled From version 63: this feature is behind the
javascript.options.shared_memory preference (needs to be set to true ). To change preferences in Firefox, visit about:config.
- 57
Disabled
- Support was disabled by default to mitigate speculative execution side-channel attacks (Mozilla Security Blog).
- Uses the non-standard name:
wake
- Disabled From version 57: this feature is behind the
javascript.options.shared_memory preference (needs to be set to true ). To change preferences in Firefox, visit about:config.
- 55 — 57
- 48 — 55
Disabled
- Disabled From version 48 until version 55 (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.
- 46 — 48
Disabled
- The
count parameter defaults to 0 instead of the later-specified +Infinity .
- Uses the non-standard name:
futexWake
- Disabled From version 46 until version 48 (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.
|
No |
No |
10.1 — ?
- 10.1 — ?
- Uses the non-standard name:
wake
|
|
Mobile |
|
Android webview |
Chrome for Android |
Edge Mobile |
Firefox for Android |
Opera for Android |
iOS Safari |
Samsung Internet |
Basic support |
60 — 63
- 60 — 63
- Chrome disabled
SharedArrayBuffer on January 5, 2018 to help reduce the efficacy of speculative side-channel attacks. This is intended as a temporary measure until other mitigations are in place.
- Uses the non-standard name:
wake
|
60 — 63
- 60 — 63
- Chrome disabled
SharedArrayBuffer on January 5, 2018 to help reduce the efficacy of speculative side-channel attacks. This is intended as a temporary measure until other mitigations are in place.
- Uses the non-standard name:
wake
|
? |
63 Disabled
- 63
Disabled
- Support was disabled by default to mitigate speculative execution side-channel attacks (Mozilla Security Blog).
- Disabled From version 63: this feature is behind the
javascript.options.shared_memory preference (needs to be set to true ). To change preferences in Firefox, visit about:config.
- 57
Disabled
- Support was disabled by default to mitigate speculative execution side-channel attacks (Mozilla Security Blog).
- Uses the non-standard name:
wake
- Disabled From version 57: this feature is behind the
javascript.options.shared_memory preference (needs to be set to true ). To change preferences in Firefox, visit about:config.
- 55 — 57
- 48 — 55
Disabled
- Disabled From version 48 until version 55 (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.
- 46 — 48
Disabled
- The
count parameter defaults to 0 instead of the later-specified +Infinity .
- Uses the non-standard name:
futexWake
- Disabled From version 46 until version 48 (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.
|
No |
No |
No |
|
Server |
|
Node.js |
Basic support |
8.10.0
- 8.10.0
- Uses the non-standard name:
wake
|
See also