Detailed Description

Defines the User Kernels, which are a method to extend OpenVX with new vision functions.

User Kernels can be loaded by OpenVX and included as nodes in the graph or as immediate functions (if the Client supplies the interface). User Kernels will typically be loaded and executed on High Level Operating System/CPU compatible targets, not on remote processors or other accelerators. This specification does not mandate what constitutes compatible platforms.

Call sequence of User Kernels Installation

Call sequence of a Graph Verify and Release with User Kernels.

Call sequence of a Graph Execution with User Kernels

During the first graph verification, the implementation will perform the following action sequence:

Initialize local data node attributes
- If VX_KERNEL_LOCAL_DATA_SIZE == 0, then set VX_NODE_LOCAL_DATA_SIZE to 0 and set VX_NODE_LOCAL_DATA_PTR to NULL.
- If VX_KERNEL_LOCAL_DATA_SIZE != 0, set VX_NODE_LOCAL_DATA_SIZE to VX_KERNEL_LOCAL_DATA_SIZE and set VX_NODE_LOCAL_DATA_PTR to the address of a buffer of VX_KERNEL_LOCAL_DATA_SIZE bytes.
Call the vx_kernel_validate_f callback.
Call the vx_kernel_initialize_f callback (if not NULL):
- If VX_KERNEL_LOCAL_DATA_SIZE == 0, the callback is allowed to set VX_NODE_LOCAL_DATA_SIZE and VX_NODE_LOCAL_DATA_PTR.
- If VX_KERNEL_LOCAL_DATA_SIZE != 0, then any attempt by the callback to set VX_NODE_LOCAL_DATA_SIZE or VX_NODE_LOCAL_DATA_PTR attributes will generate an error.
Provide the buffer optionally requested by the application
- If VX_KERNEL_LOCAL_DATA_SIZE == 0 and VX_NODE_LOCAL_DATA_SIZE != 0, and VX_NODE_LOCAL_DATA_PTR == NULL, then the implementation will set VX_NODE_LOCAL_DATA_PTR to the address of a buffer of VX_NODE_LOCAL_DATA_SIZE bytes.

At node destruction time, the implementation will perform the following action sequence:

Call vx_kernel_deinitialize_f callback (if not NULL): If the VX_NODE_LOCAL_DATA_PTR was set earlier by the implementation, then any attempt by the callback to set the VX_NODE_LOCAL_DATA_PTR attributes will generate an error.
If the VX_NODE_LOCAL_DATA_PTR was set earlier by the implementation, then the pointed memory must not be used anymore by the application after the vx_kernel_deinitialize_f callback completes.

A user node requires re-verification, if any changes below occurred after the last node verification:

The VX_NODE_BORDER node attribute was modified.
At least one of the node parameters was replaced by a data object with different meta-data, or was replaced by the 0 reference for optional parameters, or was set to a data object if previously not set because optional.

The node re-verification can by triggered explicitly by the application by calling vxVerifyGraph that will perform a complete graph verification. Otherwise, it will be triggered automatically at the next graph execution.

During user node re-verification, the following action sequence will occur:

Call the vx_kernel_deinitialize_f callback (if not NULL): If the VX_NODE_LOCAL_DATA_PTR was set earlier by the OpenVX implementation, then any attempt by the callback to set the VX_NODE_LOCAL_DATA_PTR attributes will generate an error.
Reinitialize local data node attributes if needed If VX_KERNEL_LOCAL_DATA_SIZE == 0:
- set VX_NODE_LOCAL_DATA_PTR to NULL.
- set VX_NODE_LOCAL_DATA_SIZE to 0.
Call the vx_kernel_validate_f callback.
Call the vx_kernel_initialize_f callback (if not NULL):
- If VX_KERNEL_LOCAL_DATA_SIZE == 0, the callback is allowed to set VX_NODE_LOCAL_DATA_SIZE and VX_NODE_LOCAL_DATA_PTR.
- If VX_KERNEL_LOCAL_DATA_SIZE is != 0, then any attempt by the callback to set VX_NODE_LOCAL_DATA_SIZE or VX_NODE_LOCAL_DATA_PTR attributes will generate an error.
Provide the buffer optionally requested by the application
- If VX_KERNEL_LOCAL_DATA_SIZE == 0 and VX_NODE_LOCAL_DATA_SIZE != 0, and VX_NODE_LOCAL_DATA_PTR == NULL, then the OpenVX implementation will set VX_NODE_LOCAL_DATA_PTR to the address of a buffer of VX_NODE_LOCAL_DATA_SIZE bytes.

When an OpenVX implementation sets the VX_NODE_LOCAL_DATA_PTR, the data inside the buffer will not be persistent between kernel executions.

Typedefs
typedef vx_status(*	vx_kernel_deinitialize_f) (vx_node node, const vx_reference *parameters, vx_uint32 num)
	The pointer to the kernel deinitializer. If the host code requires a call to deinitialize data during a node garbage collection, this function is called if not NULL. More...

typedef vx_status(*	vx_kernel_f) (vx_node node, const vx_reference *parameters, vx_uint32 num)
	The pointer to the Host side kernel. More...

typedef vx_status(*	vx_kernel_image_valid_rectangle_f) (vx_node node, vx_uint32 index, const vx_rectangle_t const input_valid[], vx_rectangle_t const output_valid[])
	A user-defined callback function to set the valid rectangle of an output image. More...

typedef vx_status(*	vx_kernel_initialize_f) (vx_node node, const vx_reference *parameters, vx_uint32 num)
	The pointer to the kernel initializer. If the host code requires a call to initialize data once all the parameters have been validated, this function is called if not NULL. More...

typedef vx_status(*	vx_kernel_validate_f) (vx_node node, const vx_reference parameters[], vx_uint32 num, vx_meta_format metas[])
	The user-defined kernel node parameters validation function. The function only needs to fill in the meta data structure(s). More...

typedef struct _vx_meta_format *	vx_meta_format
	This object is used by output validation functions to specify the meta data of the expected output data object. More...

typedef vx_status(*	vx_publish_kernels_f) (vx_context context)
	The type of the `vxPublishKernels` entry function of modules loaded by `vxLoadKernels` and unloaded by `vxUnloadKernels`. More...

typedef vx_status(*	vx_unpublish_kernels_f) (vx_context context)
	The type of the `vxUnpublishKernels` entry function of modules loaded by `vxLoadKernels` and unloaded by `vxUnloadKernels`. More...

Enumerations
enum	vx_meta_valid_rect_attribute_e { VX_VALID_RECT_CALLBACK = ((( VX_ID_KHRONOS ) << 20) \| ( VX_TYPE_META_FORMAT << 8)) + 0x1 }
	The meta valid rectangle attributes. More...

Functions
vx_status VX_API_CALL	vxAddParameterToKernel (vx_kernel kernel, vx_uint32 index, vx_enum dir, vx_enum data_type, vx_enum state)
	Allows users to set the signatures of the custom kernel. More...

vx_kernel VX_API_CALL	vxAddUserKernel (vx_context context, const vx_char name[VX_MAX_KERNEL_NAME], vx_enum enumeration, vx_kernel_f func_ptr, vx_uint32 numParams, vx_kernel_validate_f validate, vx_kernel_initialize_f init, vx_kernel_deinitialize_f deinit)
	Allows users to add custom kernels to a context at run-time. More...

vx_status VX_API_CALL	vxAllocateUserKernelId (vx_context context, vx_enum *pKernelEnumId)
	Allocates and registers user-defined kernel enumeration to a context. The allocated enumeration is from available pool of 4096 enumerations reserved for dynamic allocation from VX_KERNEL_BASE(VX_ID_USER,0). More...

vx_status VX_API_CALL	vxAllocateUserKernelLibraryId (vx_context context, vx_enum *pLibraryId)
	Allocates and registers user-defined kernel library ID to a context. More...

vx_status VX_API_CALL	vxFinalizeKernel (vx_kernel kernel)
	This API is called after all parameters have been added to the kernel and the kernel is ready to be used. Notice that the reference to the kernel created by vxAddUserKernel is still valid after the call to vxFinalizeKernel. If an error occurs, the kernel is not available for usage by the clients of OpenVX. Typically this is due to a mismatch between the number of parameters requested and given. More...

vx_status VX_API_CALL	vxLoadKernels (vx_context context, const vx_char *module)
	Loads a library of kernels, called module, into a context. More...

vx_status VX_API_CALL	vxRemoveKernel (vx_kernel kernel)
	Removes a custom kernel from its context and releases it. More...

vx_status VX_API_CALL	vxSetKernelAttribute (vx_kernel kernel, vx_enum attribute, const void *ptr, vx_size size)
	Sets kernel attributes. More...

vx_status VX_API_CALL	vxSetMetaFormatAttribute (vx_meta_format meta, vx_enum attribute, const void *ptr, vx_size size)
	This function allows a user to set the attributes of a `vx_meta_format` object in a kernel output validator. More...

vx_status VX_API_CALL	vxSetMetaFormatFromReference (vx_meta_format meta, vx_reference exemplar)
	Set a meta format object from an exemplar data object reference. More...

vx_status VX_API_CALL	vxUnloadKernels (vx_context context, const vx_char *module)
	Unloads all kernels from the OpenVX context that had been loaded from the module using the vxLoadKernels function. More...

Typedef Documentation

typedef struct _vx_meta_format* vx_meta_format

This object is used by output validation functions to specify the meta data of the expected output data object.

Note: When the actual output object of the user node is virtual, the information given through the vx_meta_format object allows the OpenVX framework to automatically create the data object when meta data were not specified by the application at object creation time.

Definition at line 320 of file vx_types.h.

typedef vx_status( * vx_publish_kernels_f) (vx_context context)

The type of the vxPublishKernels entry function of modules loaded by vxLoadKernels and unloaded by vxUnloadKernels.

Parameters

[in] context The reference to the context kernels must be added to.

Definition at line 1744 of file vx_types.h.

typedef vx_status( * vx_unpublish_kernels_f) (vx_context context)

The type of the vxUnpublishKernels entry function of modules loaded by vxLoadKernels and unloaded by vxUnloadKernels.

Parameters

[in] context The reference to the context kernels have been added to.

Definition at line 1752 of file vx_types.h.

typedef vx_status( * vx_kernel_f) (vx_node node, const vx_reference *parameters, vx_uint32 num)

The pointer to the Host side kernel.

Parameters

[in]	node	The handle to the node that contains this kernel.
[in]	parameters	The array of parameter references.
[in]	num	The number of parameters.

Definition at line 1761 of file vx_types.h.

typedef vx_status( * vx_kernel_initialize_f) (vx_node node, const vx_reference *parameters, vx_uint32 num)

The pointer to the kernel initializer. If the host code requires a call to initialize data once all the parameters have been validated, this function is called if not NULL.

Parameters

[in]	node	The handle to the node that contains this kernel.
[in]	parameters	The array of parameter references.
[in]	num	The number of parameters.

Definition at line 1772 of file vx_types.h.

typedef vx_status( * vx_kernel_deinitialize_f) (vx_node node, const vx_reference *parameters, vx_uint32 num)

The pointer to the kernel deinitializer. If the host code requires a call to deinitialize data during a node garbage collection, this function is called if not NULL.

Parameters

[in]	node	The handle to the node that contains this kernel.
[in]	parameters	The array of parameter references.
[in]	num	The number of parameters.

Definition at line 1783 of file vx_types.h.

typedef vx_status( * vx_kernel_validate_f) (vx_node node, const vx_reference parameters[], vx_uint32 num, vx_meta_format metas[])

The user-defined kernel node parameters validation function. The function only needs to fill in the meta data structure(s).

Note: This function is called once for whole set of parameters.

Parameters

[in]	node	The handle to the node that is being validated.
[in]	parameters	The array of parameters to be validated.
[in]	num	Number of parameters to be validated.
[in]	metas	A pointer to a pre-allocated array of structure references that the system holds. The system pre-allocates a number of vx_meta_format structures for the output parameters only, indexed by the same indices as parameters[]. The validation function fills in the correct type, format, and dimensionality for the system to use either to create memory or to check against existing memory.

Returns: An error code describing the validation status on parameters.

Definition at line 1799 of file vx_types.h.

typedef vx_status( * vx_kernel_image_valid_rectangle_f) (vx_node node, vx_uint32 index, const vx_rectangle_t *const input_valid[], vx_rectangle_t *const output_valid[])

A user-defined callback function to set the valid rectangle of an output image.

The VX_VALID_RECT_CALLBACK attribute in the vx_meta_format object should be set to the desired callback during user node's output validator. The callback must not call vxGetValidRegionImage or vxSetImageValidRectangle. Instead, an array of the valid rectangles of all the input images is supplied to the callback to calculate the output valid rectangle. The output of the user node may be a pyramid, or just an image. If it is just an image, the 'Out' array associated with that output only has one element. If the output is a pyramid, the array size is equal to the number of pyramid levels. Notice that the array memory allocation passed to the callback is managed by the framework, the application must not allocate or deallocate those pointers.

The behavior of the callback function vx_kernel_image_valid_rectangle_f is undefined if one of the following is true:

One of the input arguments of a user node is a pyramid or an array of images.
Either input or output argument of a user node is an array of pyramids.

Parameters

[in,out]	node	The handle to the node that is being validated.
[in]	index	The index of the output parameter for which a valid region should be set.
[in]	input_valid	A pointer to an array of valid regions of input images or images contained in image container (e.g. pyramids). They are provided in same order as the parameter list of the kernel's declaration.
[out]	output_valid	An array of valid regions that should be set for the output images or image containers (e.g. pyramid) after graph processing. The length of the array should be equal to the size of the image container (e.g. number of levels in the pyramid). For a simple output image the array size is always one. Each rectangle supplies the valid region for one image. The array memory allocation is managed by the framework.

Returns: An error code describing the validation status on parameters.

Definition at line 1832 of file vx_types.h.

Enumeration Type Documentation

enum vx_meta_valid_rect_attribute_e

The meta valid rectangle attributes.

Enumerator
VX_VALID_RECT_CALLBACK	Valid rectangle callback during output parameter validation. Write-only.

Definition at line 1183 of file vx_types.h.

Function Documentation

vx_status VX_API_CALL vxAllocateUserKernelId	(	vx_context	context,
		vx_enum *	pKernelEnumId
	)

Allocates and registers user-defined kernel enumeration to a context. The allocated enumeration is from available pool of 4096 enumerations reserved for dynamic allocation from VX_KERNEL_BASE(VX_ID_USER,0).

Parameters

[in]	context	The reference to the implementation context.
[out]	pKernelEnumId	pointer to return `vx_enum` for user-defined kernel.

Return values

VX_SUCCESS	No errors; any other value indicates failure.
VX_ERROR_INVALID_REFERENCE	If the context is not a valid `vx_context` reference.
VX_ERROR_NO_RESOURCES	The enumerations has been exhausted.

vx_status VX_API_CALL vxAllocateUserKernelLibraryId	(	vx_context	context,
		vx_enum *	pLibraryId
	)

Allocates and registers user-defined kernel library ID to a context.

The allocated library ID is from available pool of library IDs (1..255) reserved for dynamic allocation. The returned libraryId can be used by user-kernel library developer to specify individual kernel enum IDs in a header file, shown below:

 #define MY_KERNEL_ID1(libraryId) (VX_KERNEL_BASE(VX_ID_USER,libraryId) + 0);
 #define MY_KERNEL_ID2(libraryId) (VX_KERNEL_BASE(VX_ID_USER,libraryId) + 1);
 #define MY_KERNEL_ID3(libraryId) (VX_KERNEL_BASE(VX_ID_USER,libraryId) + 2);

Parameters

[in]	context	The reference to the implementation context.
[out]	pLibraryId	pointer to `vx_enum` for user-kernel libraryId.

Return values

VX_SUCCESS	No errors; any other value indicates failure.
VX_ERROR_NO_RESOURCES	The enumerations has been exhausted.

vx_status VX_API_CALL vxLoadKernels	(	vx_context	context,
		const vx_char *	module
	)

Loads a library of kernels, called module, into a context.

The module must be a dynamic library with by convention, two exported functions named vxPublishKernels and vxUnpublishKernels.

vxPublishKernels must have type vx_publish_kernels_f, and must add kernels to the context by calling vxAddUserKernel for each new kernel. vxPublishKernels is called by vxLoadKernels.

vxUnpublishKernels must have type vx_unpublish_kernels_f, and must remove kernels from the context by calling vxRemoveKernel for each kernel the vxPublishKernels has added. vxUnpublishKernels is called by vxUnloadKernels.

Note: When all references to loaded kernels are released, the module may be automatically unloaded.

Parameters

[in]	context	The reference to the context the kernels must be added to.
[in]	module	The short name of the module to load. On systems where there are specific naming conventions for modules, the name passed should ignore such conventions. For example: `libxyz.so` should be passed as just `xyz` and the implementation will do the right thing that the platform requires.

Note: This API uses the system pre-defined paths for modules.

Returns: A vx_status_e enumeration.

Return values

VX_SUCCESS	No errors; any other value indicates failure.
VX_ERROR_INVALID_REFERENCE	context is not a valid `vx_context` reference.
VX_ERROR_INVALID_PARAMETERS	If any of the other parameters are incorrect.

See also: vxGetKernelByName

vx_status VX_API_CALL vxUnloadKernels	(	vx_context	context,
		const vx_char *	module
	)

Unloads all kernels from the OpenVX context that had been loaded from the module using the vxLoadKernels function.

The kernel unloading is performed by calling the vxUnpublishKernels exported function of the module.

Note: vxUnpublishKernels is defined in the description of vxLoadKernels.

Parameters

[in]	context	The reference to the context the kernels must be removed from.
[in]	module	The short name of the module to unload. On systems where there are specific naming conventions for modules, the name passed should ignore such conventions. For example: `libxyz.so` should be passed as just `xyz` and the implementation will do the right thing that the platform requires.

Note: This API uses the system pre-defined paths for modules.

Returns: A vx_status_e enumeration.

Return values

VX_SUCCESS	No errors; any other value indicates failure.
VX_ERROR_INVALID_REFERENCE	context is not a valid `vx_context` reference.
VX_ERROR_INVALID_PARAMETERS	If any of the other parameters are incorrect.

See also: vxLoadKernels

vx_kernel VX_API_CALL vxAddUserKernel	(	vx_context	context,
		const vx_char	name[VX_MAX_KERNEL_NAME],
		vx_enum	enumeration,
		vx_kernel_f	func_ptr,
		vx_uint32	numParams,
		vx_kernel_validate_f	validate,
		vx_kernel_initialize_f	init,
		vx_kernel_deinitialize_f	deinit
	)

Allows users to add custom kernels to a context at run-time.

Parameters

[in]	context	The reference to the context the kernel must be added to.
[in]	name	The string to use to match the kernel.
[in]	enumeration	The enumerated value of the kernel to be used by clients.
[in]	func_ptr	The process-local function pointer to be invoked.
[in]	numParams	The number of parameters for this kernel.
[in]	validate	The pointer to `vx_kernel_validate_f`, which validates parameters to this kernel.
[in]	init	The kernel initialization function.
[in]	deinit	The kernel de-initialization function.

Returns: A vx_kernel reference. Any possible errors preventing a successful creation should be checked using vxGetStatus.

vx_status VX_API_CALL vxFinalizeKernel ( vx_kernel kernel )

This API is called after all parameters have been added to the kernel and the kernel is ready to be used. Notice that the reference to the kernel created by vxAddUserKernel is still valid after the call to vxFinalizeKernel. If an error occurs, the kernel is not available for usage by the clients of OpenVX. Typically this is due to a mismatch between the number of parameters requested and given.

Parameters

[in] kernel The reference to the loaded kernel from vxAddUserKernel.

Returns: A vx_status_e enumeration.

Return values

VX_SUCCESS	No errors; any other value indicates failure.
VX_ERROR_INVALID_REFERENCE	kernel is not a valid `vx_kernel` reference.

Precondition: vxAddUserKernel and vxAddParameterToKernel

vx_status VX_API_CALL vxAddParameterToKernel	(	vx_kernel	kernel,
		vx_uint32	index,
		vx_enum	dir,
		vx_enum	data_type,
		vx_enum	state
	)

Allows users to set the signatures of the custom kernel.

Parameters

[in]	kernel	The reference to the kernel added with `vxAddUserKernel`.
[in]	index	The index of the parameter to add.
[in]	dir	The direction of the parameter. This must be either `VX_INPUT` or `VX_OUTPUT`. `VX_BIDIRECTIONAL` is not supported for this function.
[in]	data_type	The type of parameter. This must be a value from `vx_type_e`.
[in]	state	The state of the parameter (required or not). This must be a value from `vx_parameter_state_e`.

Returns: A vx_status_e enumerated value.

Return values

VX_SUCCESS	Parameter is successfully set on kernel; any other value indicates failure.
VX_ERROR_INVALID_REFERENCE	kernel is not a valid `vx_kernel` reference.
VX_ERROR_INVALID_PARAMETERS	If the parameter is not valid for any reason.

Precondition: vxAddUserKernel

vx_status VX_API_CALL vxRemoveKernel ( vx_kernel kernel )

Removes a custom kernel from its context and releases it.

Parameters

[in] kernel The reference to the kernel to remove. Returned from vxAddUserKernel.

Note: Any kernel enumerated in the base standard cannot be removed; only kernels added through vxAddUserKernel can be removed.

Returns: A vx_status_e enumeration. The function returns to the application full control over the memory resources provided at the kernel creation time.

Return values

VX_SUCCESS	No errors; any other value indicates failure.
VX_ERROR_INVALID_REFERENCE	kernel is not a valid `vx_kernel` reference.
VX_ERROR_INVALID_PARAMETERS	If a base kernel is passed in.
VX_FAILURE	If the application has not released all references to the kernel object OR if the application has not released all references to a node that is using this kernel OR if the application has not released all references to a graph which has nodes that is using this kernel.

vx_status VX_API_CALL vxSetKernelAttribute	(	vx_kernel	kernel,
		vx_enum	attribute,
		const void *	ptr,
		vx_size	size
	)

Sets kernel attributes.

Parameters

[in]	kernel	The reference to the kernel.
[in]	attribute	The enumeration of the attributes. See `vx_kernel_attribute_e`.
[in]	ptr	The pointer to the location from which to read the attribute.
[in]	size	The size in bytes of the data area indicated by ptr in bytes.

Note: After a kernel has been passed to vxFinalizeKernel, no attributes can be altered.

Returns: A vx_status_e enumeration.

Return values

VX_SUCCESS	No errors; any other value indicates failure.
VX_ERROR_INVALID_REFERENCE	kernel is not a valid `vx_kernel` reference.

vx_status VX_API_CALL vxSetMetaFormatAttribute	(	vx_meta_format	meta,
		vx_enum	attribute,
		const void *	ptr,
		vx_size	size
	)

This function allows a user to set the attributes of a vx_meta_format object in a kernel output validator.

The vx_meta_format object contains two types of information: data object meta data and some specific information that defines how the valid region of an image changes

The meta data attributes that can be set are identified by this list:

vx_image : VX_IMAGE_FORMAT, VX_IMAGE_HEIGHT, VX_IMAGE_WIDTH
vx_array : VX_ARRAY_CAPACITY, VX_ARRAY_ITEMTYPE
vx_pyramid : VX_PYRAMID_FORMAT, VX_PYRAMID_HEIGHT, VX_PYRAMID_WIDTH, VX_PYRAMID_LEVELS, VX_PYRAMID_SCALE
vx_scalar : VX_SCALAR_TYPE
vx_matrix : VX_MATRIX_TYPE, VX_MATRIX_ROWS, VX_MATRIX_COLUMNS
vx_distribution : VX_DISTRIBUTION_BINS, VX_DISTRIBUTION_OFFSET, VX_DISTRIBUTION_RANGE
vx_remap : VX_REMAP_SOURCE_WIDTH, VX_REMAP_SOURCE_HEIGHT, VX_REMAP_DESTINATION_WIDTH, VX_REMAP_DESTINATION_HEIGHT
vx_lut : VX_LUT_TYPE, VX_LUT_COUNT
vx_threshold : VX_THRESHOLD_TYPE, VX_THRESHOLD_INPUT_FORMAT, VX_THRESHOLD_INPUT_FORMAT
vx_object_array : VX_OBJECT_ARRAY_NUMITEMS, VX_OBJECT_ARRAY_ITEMTYPE
vx_tensor : VX_TENSOR_NUMBER_OF_DIMS, VX_TENSOR_DIMS, VX_TENSOR_DATA_TYPE, VX_TENSOR_FIXED_POINT_POSITION

VX_VALID_RECT_CALLBACK

Note: For vx_image, a specific attribute can be used to specify the valid region evolution. This information is not a meta data.

Parameters

[in]	meta	The reference to the vx_meta_format struct to set
[in]	attribute	Use the subset of data object attributes that define the meta data of this object or attributes from `vx_meta_format`.
[in]	ptr	The input pointer of the value to set on the meta format object.
[in]	size	The size in bytes of the object to which ptr points.

Returns: A vx_status_e enumeration.

Return values

VX_SUCCESS	The attribute was set; any other value indicates failure.
VX_ERROR_INVALID_REFERENCE	meta is not a valid `vx_meta_format` reference.
VX_ERROR_INVALID_PARAMETERS	size was not correct for the type needed.
VX_ERROR_NOT_SUPPORTED	the object attribute was not supported on the meta format object.
VX_ERROR_INVALID_TYPE	attribute type did not match known meta format type.

vx_status VX_API_CALL vxSetMetaFormatFromReference	(	vx_meta_format	meta,
		vx_reference	exemplar
	)

Set a meta format object from an exemplar data object reference.

This function sets a vx_meta_format object from the meta data of the exemplar

Parameters

[in]	meta	The meta format object to set
[in]	exemplar	The exemplar data object.

Returns: A vx_status_e enumeration.

Return values

VX_SUCCESS	The meta format was correctly set; any other value indicates failure.
VX_ERROR_INVALID_REFERENCE	meta is not a valid `vx_meta_format` reference, or exemplar is not a valid `vx_reference` reference.

Detailed Description

Typedefs

Enumerations

Functions

Typedef Documentation

Enumeration Type Documentation

Function Documentation