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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);



Refers to the platform ID returned by clGetPlatformIDs(3clc) or can be NULL. If platform is NULL, the behavior is implementation-defined.


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.


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.


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.


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


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


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

•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.


OpenCL Specification[1]


clGetDeviceInfo(3clc), clGetPlatformIDs(3clc), clCreateContext(3clc), classDiagram(3clc)


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OpenCL Specification
page 35, section 4.2 - Querying Devices
01/14/2021 The Khronos Group