C Specification

To query information about a command-queue, call the function

// Provided by CL_VERSION_1_0
cl_int clGetCommandQueueInfo(
    cl_command_queue command_queue,
    cl_command_queue_info param_name,
    size_t param_value_size,
    void* param_value,
    size_t* param_value_size_ret);

Parameters

  • command_queue specifies the command-queue being queried.

  • param_name specifies the information to query.

  • param_value is a pointer to memory where the appropriate result being queried is returned. If param_value is NULL, it is ignored.

  • param_value_size specifies the size in bytes of memory pointed to by param_value. This size must be greater than or equal to the size of the return type specified in the Command-Queue Queries table. If param_value is NULL, it is ignored.

  • param_value_size_ret returns the actual size in bytes of data being queried by param_name. If param_value_size_ret is NULL, it is ignored.

Description

The list of supported param_name values and the information returned in param_value by clGetCommandQueueInfo is described in the Command-Queue Queries table.

Table 1. List of supported param_names by clGetCommandQueueInfo
Queue Info Return Type Description

CL_QUEUE_CONTEXT

cl_context

Return the context specified when the command-queue is created.

CL_QUEUE_DEVICE

cl_device_id

Return the device specified when the command-queue is created.

CL_QUEUE_REFERENCE_COUNT [1]

cl_uint

Return the command-queue reference count.

CL_QUEUE_PROPERTIES

cl_command_queue_properties

Return the currently specified properties for the command-queue. These properties are specified by the value associated with the CL_QUEUE_PROPERTIES passed in properties argument in clCreateCommandQueueWithProperties, or the value of the properties argument in clCreateCommandQueue.

CL_QUEUE_PROPERTIES_ARRAY

missing before version 3.0.

cl_queue_properties[]

Return the properties argument specified in clCreateCommandQueueWithProperties.

If the properties argument specified in clCreateCommandQueueWithProperties used to create command_queue was not NULL, the implementation must return the values specified in the properties argument in the same order and without including additional properties.

If command_queue was created using clCreateCommandQueue, or if the properties argument specified in clCreateCommandQueueWithProperties was NULL, the implementation must return param_value_size_ret equal to 0, indicating that there are no properties to be returned.

CL_QUEUE_SIZE

missing before version 2.0.

cl_uint

Return the size of the device command-queue. To be considered valid for this query, command_queue must be a device command-queue.

CL_QUEUE_DEVICE_DEFAULT

missing before version 2.1.

cl_command_queue

Return the current default command-queue for the underlying device.

clGetCommandQueueInfo returns CL_SUCCESS if the function is executed successfully. Otherwise, it returns one of the following errors:

  • CL_INVALID_COMMAND_QUEUE if command_queue is not a valid command-queue, or if command_queue is not a valid command-queue for param_name.

  • CL_INVALID_VALUE if param_name is not one of the supported values, or if the size in bytes specified by param_value_size is less than size of the return type specified in the Command-Queue Queries table and param_value is not NULL.

  • 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.

See Also

CL_VERSION_1_0, cl_command_queue, cl_command_queue_info

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

1. The reference count returned should be considered immediately stale. It is unsuitable for general use in applications. This feature is provided for identifying memory leaks.