C Specification

To enqueue a command to execute a native C/C++ function not compiled using the OpenCL compiler, call the function

// Provided by CL_VERSION_1_0
cl_int clEnqueueNativeKernel(
    cl_command_queue command_queue,
    void (CL_CALLBACK* user_func)(void*),
    void* args,
    size_t cb_args,
    cl_uint num_mem_objects,
    const cl_mem* mem_list,
    const void** args_mem_loc,
    cl_uint num_events_in_wait_list,
    const cl_event* event_wait_list,
    cl_event* event);

Parameters

  • command_queue is a valid host command-queue. A native user function can only be executed on a command-queue created on a device that has CL_EXEC_NATIVE_KERNEL capability set in CL_DEVICE_EXECUTION_CAPABILITIES as specified in the Device Queries table.

  • user_func is a pointer to a host-callable user function. It is the application’s responsibility to ensure that the host-callable user function is thread-safe.

  • args is a pointer to the args list that user_func should be called with.

  • cb_args is the size in bytes of the args list that args points to.

  • num_mem_objects is the number of buffer objects that are passed in args.

  • mem_list is a list of valid buffer objects, if num_mem_objects > 0. The buffer object values specified in mem_list are memory object handles (cl_mem values) returned by clCreateBuffer or clCreateBufferWithProperties, or NULL.

  • args_mem_loc is a pointer to appropriate locations that args points to where memory object handles (cl_mem values) are stored. Before the user function is executed, the memory object handles are replaced by pointers to global memory.

  • event_wait_list, num_events_in_wait_list and event are as described in clEnqueueNDRangeKernel.

Description

The data pointed to by args and cb_args bytes in size will be copied and a pointer to this copied region will be passed to user_func. The copy needs to be done because the memory objects (cl_mem values) that args may contain need to be modified and replaced by appropriate pointers to global memory. When clEnqueueNativeKernel returns, the memory region pointed to by args can be reused by the application.

clEnqueueNativeKernel returns CL_SUCCESS if the user function execution instance was successfully queued. Otherwise, it returns one of the following errors:

  • CL_INVALID_COMMAND_QUEUE if command_queue is not a valid host command-queue.

  • CL_INVALID_CONTEXT if context associated with command_queue and events in event_wait_list are not the same.

  • CL_INVALID_VALUE if user_func is NULL.

  • CL_INVALID_VALUE if args is a NULL value and cb_args > 0, or if args is a NULL value and num_mem_objects > 0.

  • CL_INVALID_VALUE if args is not NULL and cb_args is 0.

  • CL_INVALID_VALUE if num_mem_objects > 0 and mem_list or args_mem_loc are NULL.

  • CL_INVALID_VALUE if num_mem_objects = 0 and mem_list or args_mem_loc are not NULL.

  • CL_INVALID_OPERATION if the device associated with command_queue cannot execute the native kernel.

  • CL_INVALID_MEM_OBJECT if one or more memory objects specified in mem_list are not valid or are not buffer objects.

  • CL_OUT_OF_RESOURCES if there is a failure to queue the execution instance of kernel on the command-queue because of insufficient resources needed to execute the kernel.

  • CL_MEM_OBJECT_ALLOCATION_FAILURE if there is a failure to allocate memory for data store associated with buffer objects specified as arguments to kernel.

  • CL_INVALID_EVENT_WAIT_LIST if event_wait_list is NULL and num_events_in_wait_list > 0, or event_wait_list is not NULL and num_events_in_wait_list is 0, or if event objects in event_wait_list are not valid events.

  • CL_INVALID_OPERATION if SVM pointers are passed as arguments to a kernel and the device does not support SVM or if system pointers are passed as arguments to a kernel and/or stored inside SVM allocations passed as kernel arguments and the device does not support fine grain system SVM allocations.

  • CL_OUT_OF_RESOURCES if there is a failure to allocate resources required by the OpenCL implementation on the device.

  • CL_OUT_OF_HOST_MEMORY if there is a failure to allocate resources required by the OpenCL implementation on the host.

The total number of read-only images specified as arguments to a kernel cannot exceed CL_DEVICE_MAX_READ_IMAGE_ARGS. Each image array argument to a kernel declared with the read_only qualifier counts as one image. The total number of write-only images specified as arguments to a kernel cannot exceed CL_DEVICE_MAX_WRITE_IMAGE_ARGS. Each image array argument to a kernel declared with the write_only qualifier counts as one image.

The total number of read-write images specified as arguments to a kernel cannot exceed CL_DEVICE_MAX_READ_WRITE_IMAGE_ARGS. Each image array argument to a kernel declared with the read_write qualifier counts as one image.

See Also

CL_VERSION_1_0, cl_command_queue, cl_event, cl_mem, cl_uint

Document Notes

For more information, see the OpenCL Specification

This page is extracted from the OpenCL 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