clGetDeviceIDs

Obtain the list of devices available on a platform.

cl_int clGetDeviceIDs ( cl_platform_id  platform ,
  cl_device_type  device_type ,
  cl_uint  num_entries ,
  cl_device_id  *devices ,
  cl_uint  *num_devices )

Parameters

platform

Refers to the platform ID returned by clGetPlatformIDs or can be NULL. If platform is NULL, the behavior is implementation-defined.

device_type

A bitfield that identifies the type of OpenCL device. The device_type can be used to query specific OpenCL devices or all OpenCL devices available. The valid values for device_type are specified in the following table.

cl_device_type Description
CL_DEVICE_TYPE_CPU An OpenCL device that is the host processor. The host processor runs the OpenCL implementations and is a single or multi-core CPU.
CL_DEVICE_TYPE_GPU An OpenCL device that is a GPU. By this we mean that the device can also be used to accelerate a 3D API such as OpenGL or DirectX.
CL_DEVICE_TYPE_ACCELERATOR Dedicated OpenCL accelerators (for example the IBM CELL Blade). These devices communicate with the host processor using a peripheral interconnect such as PCIe.
CL_DEVICE_TYPE_CUSTOM Dedicated accelerators that do not support programs written in OpenCL C.
CL_DEVICE_TYPE_DEFAULT The default OpenCL device in the system. The default device cannot be a CL_DEVICE_TYPE_CUSTOM device.
CL_DEVICE_TYPE_ALL All OpenCL devices available in the system except CL_DEVICE_TYPE_CUSTOM devices.
num_entries

The number of cl_device_id entries that can be added to devices. If devices is not NULL, the num_entries must be greater than zero.

devices

A list of OpenCL devices found. The cl_device_id values returned in devices can be used to identify a specific OpenCL device. If devices argument is NULL, this argument is ignored. The number of OpenCL devices returned is the mininum of the value specified by num_entries or the number of OpenCL devices whose type matches device_type.

num_devices

The number of OpenCL devices available that match device_type. If num_devices is NULL, this argument is ignored.

Notes

clGetDeviceIDs may return all or a subset of the actual physical devices present in the platform and that match device_type.

Errors

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

  • CL_INVALID_PLATFORM if platform is not a valid platform.
  • CL_INVALID_DEVICE_TYPE if device_type is not a valid value.
  • CL_INVALID_VALUE if num_entries is equal to zero and devices is not NULL or if both num_devices and devices are NULL.
  • CL_DEVICE_NOT_FOUND if no OpenCL devices that matched device_type were found.
  • 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.

Specification

OpenCL Specification

Also see

clGetDeviceInfo, clGetPlatformIDs, clCreateContext, Cardinality Diagram

Copyright © 2007-2013 The Khronos Group Inc. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and/or associated documentation files (the "Materials"), to deal in the Materials without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Materials, and to permit persons to whom the Materials are furnished to do so, subject to the condition that this copyright notice and permission notice shall be included in all copies or substantial portions of the Materials.