Atomics.isLockFree() - JavaScript | MDN

Try it

console.log(Atomics.isLockFree(3));
// 3 is not one of the BYTES_PER_ELEMENT values
// Expected output: false

console.log(Atomics.isLockFree(4));
// 4 is one of the BYTES_PER_ELEMENT values
// Expected output: true

Syntax

js

Atomics.isLockFree(size)

Parameters

size

The size in bytes to check.

Return value

A true or false value indicating whether the operation is lock free.

  • Always true if size is 4, because all known platforms support 4-byte atomic operations.
  • Always false if the given size is not one of the BYTES_PER_ELEMENT property of integer TypedArray types.

Examples

Using Atomics.isLockFree()

js

Atomics.isLockFree(1); // true (platform-dependent)
Atomics.isLockFree(2); // true (platform-dependent)
Atomics.isLockFree(3); // false
Atomics.isLockFree(4); // true
Atomics.isLockFree(5); // false
Atomics.isLockFree(6); // false
Atomics.isLockFree(7); // false
Atomics.isLockFree(8); // true (platform-dependent)

Specifications

Specification
ECMAScript® 2027 Language Specification
# sec-atomics.islockfree

Browser compatibility

See also

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