oracular (3) clCreateContextFromType.3clc.gz
NAME
clCreateContextFromType - Create an OpenCL context from a device type that identifies the specific
device(s) to use.
cl_context clCreateContextFromType(const cl_context_properties *properties, cl_device_type device_type,
void (CL_CALLBACK *pfn_notify) (const char *errinfo,
const void *private_info, size_t cb, void *user_data),
void *user_data, cl_int *errcode_ret);
PARAMETERS
properties
Specifies a list of context property names and their corresponding values. Each property name is
immediately followed by the corresponding desired value. The list of supported properties is
described in the table below. properties can also be NULL in which case the platform that is
selected is implementation-defined.
If the cl_khr_gl_sharing(3clc) extension is supported, properties points to an attribute list whose
format and valid contents are identical to the properties argument of clCreateContext(3clc) which is:
properties specifies a list of context property names and their corresponding values. Each property
name is immediately followed by the corresponding desired value. The list is terminated with 0. The
list of supported properties is described in the table below. properties can be NULL in which case
the platform that is selected is implementation-defined.
┌──────────────────────────────┬────────────────────────────┬────────────────────────────────┐
│cl_context_properties enum │ Property value │ Description │
├──────────────────────────────┼────────────────────────────┼────────────────────────────────┤
│CL_CONTEXT_PLATFORM │ cl_platform_id │ Specifies the platform to │
│ │ │ use. │
├──────────────────────────────┼────────────────────────────┼────────────────────────────────┤
│CL_CONTEXT_INTEROP_USER_SYNC │ cl_bool │ Specifies whether the user │
│ │ │ is responsible for │
│ │ │ synchronization between │
│ │ │ OpenCL and other APIs. │
│ │ │ Please refer to the specific │
│ │ │ sections in the OpenCL 1.2 │
│ │ │ extension specification that │
│ │ │ describe sharing with other │
│ │ │ APIs for restrictions on │
│ │ │ using this flag. If │
│ │ │ CL_CONTEXT_INTEROP_USER_SYNC │
│ │ │ is not specified, a default │
│ │ │ of CL_FALSE is assumed. │
├──────────────────────────────┼────────────────────────────┼────────────────────────────────┤
│CL_CONTEXT_D3D10_DEVICE_KHR │ ID3D10Device * │ Specifies the ID3D10Device * │
│ │ │ to use for Direct3D 10 │
│ │ │ interoperability. The │
│ │ │ default value is NULL │
│ │ │ (applies if the extension │
│ │ │ cl_khr_d3d10_sharing(3clc) │
│ │ │ is supported) │
├──────────────────────────────┼────────────────────────────┼────────────────────────────────┤
│CL_CONTEXT_ADAPTER_D3D9_KHR │ IDirect3DDevice9 * │ Specifies an │
│ │ │ IDirect3DDevice9 to use for │
│ │ │ D3D9 intero (applies if the │
│ │ │ cl_khr_dx9_media_sharing(3clc) │
│ │ │ extension is supported) │
├──────────────────────────────┼────────────────────────────┼────────────────────────────────┤
│CL_CONTEXT_ADAPTER_D3D9EX_KHR │ IDirect3DDeviceEx* │ Specifies an │
│ │ │ IDirect3DDevice9Ex to use for │
│ │ │ D3D9 interop (applies if the │
│ │ │ cl_khr_dx9_media_sharing(3clc) │
│ │ │ extension is supported) │
├──────────────────────────────┼────────────────────────────┼────────────────────────────────┤
│CL_CONTEXT_ADAPTER_DXVA_KHR │ IDXVAHD_Device * │ Specifies an IDXVAHD_Device to │
│ │ │ use for DXVA interop (applies │
│ │ │ if the │
│ │ │ cl_khr_dx9_media_sharing(3clc) │
│ │ │ extension is supported) │
├──────────────────────────────┼────────────────────────────┼────────────────────────────────┤
│CL_GL_CONTEXT_KHR │ 0, OpenGL context handle │ OpenGL context to associated │
│ │ │ the OpenCL context with │
│ │ │ (available if the │
│ │ │ cl_khr_gl_sharing(3clc) │
│ │ │ extension is enabled) │
├──────────────────────────────┼────────────────────────────┼────────────────────────────────┤
│CL_CGL_SHAREGROUP_KHR │ 0, CGL share group handle │ CGL share group to associate │
│ │ │ the OpenCL context with │
│ │ │ (available if the │
│ │ │ cl_khr_gl_sharing(3clc) │
│ │ │ extension is enabled) │
├──────────────────────────────┼────────────────────────────┼────────────────────────────────┤
│CL_EGL_DISPLAY_KHR │ EGL_NO_DISPLAY, EGLDisplay │ CGL share group to associate │
│ │ handle │ the OpenCL context with │
│ │ │ (available if the │
│ │ │ cl_khr_gl_sharing(3clc) │
│ │ │ extension is enabled) │
├──────────────────────────────┼────────────────────────────┼────────────────────────────────┤
│CL_GLX_DISPLAY_KHR │ None, X handle │ X Display an OpenGL context │
│ │ │ was created with respect to │
│ │ │ (available if the │
│ │ │ cl_khr_gl_sharing(3clc) │
│ │ │ extension is enabled) │
├──────────────────────────────┼────────────────────────────┼────────────────────────────────┤
│CL_WGL_HDC_KHR │ 0, HDC handle │ HDC an OpenGL context was │
│ │ │ created with respect to │
│ │ │ (available if the │
│ │ │ cl_khr_gl_sharing(3clc) │
│ │ │ extension is enabled) │
├──────────────────────────────┼────────────────────────────┼────────────────────────────────┤
│CL_CONTEXT_D3D11_DEVICE_KHR │ ID3D11Device * │ Specifies the ID3D11Device * │
│ │ │ to use for Direct3D 11 │
│ │ │ interoperability. The default │
│ │ │ value is NULL * (applies if │
│ │ │ the cl_khr_d3d11_sharing(3clc) │
│ │ │ extension is supported) │
└──────────────────────────────┴────────────────────────────┴────────────────────────────────┘
device_type
A bit-field that identifies the type of device and is described in the table below.
┌───────────────────────────┬───────────────────────────────────────┐
│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. │
└───────────────────────────┴───────────────────────────────────────┘
pfn_notify
A callback function that can be registered by the application. This callback function will be used by
the OpenCL implementation to report information on errors that occur in this context. This callback
function may be called asynchronously by the OpenCL implementation. It is the application's
responsibility to ensure that the callback function is thread-safe. If pfn_notify is NULL, no
callback function is registered. The parameters to this callback function are:
errinfo is a pointer to an error string.
private_info and cb represent a pointer to binary data that is returned by the OpenCL implementation
that can be used to log additional information helpful in debugging the error.
user_data is a pointer to user supplied data.
There are a number of cases where error notifications need to be delivered due to an error that
occurs outside a context. Such notifications may not be delivered through the pfn_notify callback.
Where these notifications go is implementation-defined.
user_data
Passed as the user_data argument when pfn_notify is called. user_data can be NULL.
errcode_ret
Return an appropriate error code. If errcode_ret is NULL, no error code is returned.
DESCRIPTION
Only devices that are returned by clGetDeviceIDs(3clc) for device_type are used to create the context. The context does not reference any sub-devices that may have been created from these devices.
NOTES
clCreateContextFromType may return all or a subset of the actual physical devices present in the platform
and that match device_type.
clCreateContextFromType and clCreateContext(3clc) perform an implicit retain. This is very helpful for
3rd party libraries, which typically get a context passed to them by the application. However, it is
possible that the application may delete the context without informing the library. Allowing functions to
attach to (i.e. retain) and release a context solves the problem of a context being used by a library no
longer being valid.
ERRORS
clCreateContextFromType returns a valid non-zero context and errcode_ret is set to CL_SUCCESS if the
context is created successfully. Otherwise, it returns a NULL value with the following error vlaues
returned in errcode_ret:
• CL_INVALID_PLATFORM if properties is NULL and no platform could be selected or if platform value
specified in properties is not a valid platform. If the cl_khr_gl_sharing(3clc) extension is
supported, this error is replaced (or not) by CL_INVALID_GL_SHAREGROUP_REFERENCE_KHR and possibly
CL_INVALID_OPERATION (see below and section 9.6.4 of the spec for clarification). .RE
• CL_INVALID_PROPERTY if context property name in properties is not a supported property name, or
if the value specified for a supported property name is not valid, or if the same property name
is specified more than once.
• CL_INVALID_VALUE if pfn_notify is NULL but user_data is not NULL.
• CL_INVALID_DEVICE_TYPE if device_type is not a valid value.
• CL_DEVICE_NOT_AVAILABLE if no devices that match device_type and property values specified in
properties are currently available.
• CL_DEVICE_NOT_FOUND if no devices that match device_type and property values specified in
properties 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.
• CL_INVALID_D3D10_DEVICE_KHR if the Direct3D 10 device specified for interoperability is not
compatible with the devices against which the context is to be created (if the
cl_khr_d3d10_sharing(3clc) extension is enabled).
• CL_INVALID_GL_SHAREGROUP_REFERENCE_KHR when an invalid OpenGL context or share group object
handle is specified in properties if the cl_khr_gl_sharing(3clc) extension is enabled.
• CL_INVALID_GL_SHAREGROUP_REFERENCE_KHR: If no OpenGL or OpenGL ES context or share group is
specified in the attribute list, then memory objects may not be shared, and calling any of the
commands in section 9.7 will result in this error (if the cl_khr_gl_sharing(3clc) extension is
enabled).
• CL_INVALID_GL_SHAREGROUP_REFERENCE_KHR if the cl_khr_gl_sharing(3clc) extension is enabled and
if a context was specified by any of the following means:
• Context specified for an EGL-based OpenGL ES or OpenGL implementation by setting the
attributes CL_GL_CONTEXT_KHR and CL_EGL_DISPLAY_KHR.
• Context was specified for a GLX-based OpenGL implementation by setting the attributes
CL_GL_CONTEXT_KHR and CL_GLX_DISPLAY_KHR.
• Context was specified for a WGL-based OpenGL implementation by setting the attributes
CL_GL_CONTEXT_KHR and CL_WGL_HDC_KHR.
and any of the following conditions hold:
• The specified display and context attributes 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 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 attribute CL_CGL_SHAREGROUP_KHR, and the specified share group does
not identify a valid CGL share group object (only if the cl_khr_gl_sharing(3clc) extension is
enabled).
• CL_INVALID_DX9_MEDIA_ADAPTER_KHR if the media adapter specified for interoperability is not
compatible with the devices against which the context is to be created (only if the
cl_khr_dx9_media_sharing(3clc) extension is supported).
• CL_INVALID_ADAPTER_KHR if any of the values of the properties CL_CONTEXT_ADAPTER_D3D9_KHR,
CL_CONTEXT_ADAPTER_D3D9EX_KHR or CL_CONTEXT_ADAPTER_DXVA_KHR is non-NULL and does not specify a
valid media adapter with which the cl_device_ids against which this context is to be created may
interoperate. (only if the cl_khr_dx9_media_sharing(3clc) extension is supported).
• CL_INVALID_OPERATION if interoperability is specified by setting CL_CONTEXT_ADAPTER_D3D9_KHR,
CL_CONTEXT_ADAPTER_D3D9EX_KHR or CL_CONTEXT_ADAPTER_DXVA_KHR to a non-NULL value, and
interoperability with another graphics API is also specified. (only if the
cl_khr_dx9_media_sharing(3clc) extension is supported).
• CL_INVALID_D3D11_DEVICE_KHR if the Direct3D 11 device specified for interoperability is not
compatible with the devices against which the context is to be created (only if the
cl_khr_d3d11_sharing(3clc) extension is supported).
• CL_INVALID_OPERATION if Direct3D 11 interoperability is specified by setting
CL_INVALID_D3D11_DEVICE_KHR to a non-NULL value, and interoperability with another graphics API
is also specified. (only if the cl_khr_d3d11_sharing(3clc) extension is supported).
• CL_INVALID_D3D11_DEVICE_KHR if the value of the property CL_CONTEXT_D3D11_DEVICE_KHR is non-NULL
and does not specify a valid Direct3D 11 device with which the cl_device_ids against which this
context is to be created may interoperate. (only if the cl_khr_d3d11_sharing(3clc) extension is
supported).
SPECIFICATION
OpenCL Specification[1]
SEE ALSO
clCreateContext(3clc), clGetContextInfo(3clc), clReleaseContext(3clc), clRetainContext(3clc), clGetContextInfo(3clc), classDiagram(3clc)
AUTHORS
The Khronos Group
COPYRIGHT
Copyright © 2007-2011 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.
NOTES
1. OpenCL Specification
page 56, section 4.4 - Contexts