table of contents
CLCREATECONTEXTFROMT(3clc) | OpenCL Manual | CLCREATECONTEXTFROMT(3clc) |
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¶
propertiesSpecifies 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.
device_type
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 handle | CGL share group to associate 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) |
A bit-field that identifies the type of device and is
described in the table below.
pfn_notify
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. |
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 GroupCOPYRIGHT¶
Copyright © 2007-2011 The Khronos Group Inc.NOTES¶
- 1.
- OpenCL Specification
page 56, section 4.4 - Contexts
06/18/2014 | The Khronos Group |