C Specification

To query the OpenCL device corresponding to an OpenGL context, call the function

// Provided by cl_khr_gl_sharing
cl_int clGetGLContextInfoKHR(
    const cl_context_properties* properties,
    cl_gl_context_info param_name,
    size_t param_value_size,
    void* param_value,
    size_t* param_value_size_ret);

Parameters

  • properties points to an property list whose format and valid contents are identical to the properties argument of clCreateContext. properties must identify a single valid GL context or GL share group object.

  • param_name is a constant that specifies the device types to query, and must be one of the values shown in the Supported Device Types table below.

  • param_value is a pointer to memory where the result of the query is returned, as described in the Supported Device Types table. 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 Supported Device Types 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_value. If param_value_size_ret is NULL, it is ignored.

Description

Table 1. Supported Device Types for clGetGLContextInfoKHR
param_name Return Type Information returned in param_value

CL_CURRENT_DEVICE_FOR_GL_CONTEXT_KHR

provided by the cl_khr_gl_sharing extension.

cl_device_id

Return the OpenCL device currently associated with the specified OpenGL context.

CL_DEVICES_FOR_GL_CONTEXT_KHR

provided by the cl_khr_gl_sharing extension.

cl_device_id[]

Return all OpenCL devices which may be associated with the specified OpenGL context.

clGetGLContextInfoKHR returns CL_SUCCESS if the function is executed successfully. If no device(s) exist corresponding to param_name, the call will not fail, but the value of param_value_size_ret will be zero. Otherwise, it returns one of the following errors:

  • CL_INVALID_GL_SHAREGROUP_REFERENCE_KHR if a context was specified for an OpenGL or OpenGL ES implementation using the EGL, GLX, or WGL binding APIs, as described for clCreateContext; and any of the following conditions hold:

    • The specified display and context properties do not identify a valid OpenGL or OpenGL ES context.

    • The specified context does not support buffer and renderbuffer objects.

    • The specified context is not compatible with the OpenCL context being created (for example, it exists in a physically distinct address space, such as another hardware device; or it does not support sharing data with OpenCL due to implementation restrictions).

  • CL_INVALID_GL_SHAREGROUP_REFERENCE_KHR if a share group was specified for a CGL-based OpenGL implementation by setting the property CL_CGL_SHAREGROUP_KHR, and the specified share group does not identify a valid CGL share group object.

  • CL_INVALID_OPERATION if a context was specified as described above and any of the following conditions hold:

    • A context or share group object was specified for one of CGL, EGL, GLX, or WGL and the OpenGL implementation does not support that window-system binding API.

    • More than one of the properties CL_CGL_SHAREGROUP_KHR, CL_EGL_DISPLAY_KHR, CL_GLX_DISPLAY_KHR, and CL_WGL_HDC_KHR is set to a non-default value.

    • Both of the properties CL_CGL_SHAREGROUP_KHR and CL_GL_CONTEXT_KHR are set to non-default values.

  • CL_INVALID_VALUE if a property name specified in properties is invalid.

  • 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 Supported Device Types 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_context_properties, cl_gl_context_info, cl_khr_gl_sharing

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