NumSubgroups(3)

# NumSubgroups(3) Manual Page

## Name

NumSubgroups - Number of subgroups in a workgroup

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## Description

`NumSubgroups`

  Decorating a variable with the `NumSubgroups` built-in decoration will make that variable contain the number of subgroups in the local workgroup.

Valid Usage

- VUID-NumSubgroups-NumSubgroups-04293
  The `NumSubgroups` decoration must be used only within the `GLCompute`, `MeshEXT`, `TaskEXT`, `MeshNV`, or `TaskNV` `Execution` `Model`

- VUID-NumSubgroups-NumSubgroups-04294
  The variable decorated with `NumSubgroups` must be declared using the `Input` `Storage` `Class`

- VUID-NumSubgroups-NumSubgroups-04295
  The variable decorated with `NumSubgroups` must be declared as a scalar 32-bit integer value

## See Also

No cross-references are available

## Document Notes

For more information, see the Vulkan Specification

This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.

## Copyright

Copyright 2014-2025 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0