Description

The __kernel (or kernel) qualifier declares a function to be a kernel that can be executed by an application on an OpenCL device(s). The following rules apply to functions that are declared with this qualifier:

  • It can be executed on the device only

  • It can be called by the host

  • It is just a regular function call if a __kernel function is called by another kernel function.

Kernel functions with variables declared inside the function with the __local or local qualifier can be called by the host using appropriate APIs such as clEnqueueNDRangeKernel.

The __kernel and kernel names are reserved for use as functions qualifiers and shall not be used otherwise.

See Also

accessQualifiers, optionalAttributeQualifiers

Document Notes

For more information, see the OpenCL C Specification

This page is extracted from the OpenCL C 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