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clCreateImage - Creates a 1D image, 1D image buffer, 1D image array, 2D image, 2D image array or 3D image
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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.
Errors
clCreateImage returns a valid non-zero image object and errcode_ret is set to CL_SUCCESS if the image
object is created successfully. Otherwise, it returns a NULL value with one of the following error values
returned in errcode_ret:
• CL_INVALID_CONTEXT if context is not a valid context.
• CL_INVALID_VALUE if values specified in flags are not valid.
• CL_INVALID_IMAGE_FORMAT_DESCRIPTOR if values specified in image_format are not valid or if
image_format is NULL.
• CL_INVALID_IMAGE_DESCRIPTOR if values specified in image_desc are not valid or if image_desc is NULL.
• CL_INVALID_IMAGE_SIZE if image dimensions specified in image_desc exceed the minimum maximum image
dimensions described in the table of allowed values for param_name for clGetDeviceInfo(3clc) for all
devices in context.
• CL_INVALID_HOST_PTR if host_ptr in image_desc is NULL and CL_MEM_USE_HOST_PTR or CL_MEM_COPY_HOST_PTR
are set in flags or if host_ptr is not NULL but CL_MEM_COPY_HOST_PTR or CL_MEM_USE_HOST_PTR are not
set in flags.
• CL_INVALID_VALUE if a 1D image buffer is being created and the buffer object was created with
CL_MEM_WRITE_ONLY and flags specifies CL_MEM_READ_WRITE or CL_MEM_READ_ONLY, or if the buffer object
was created with CL_MEM_READ_ONLY and flags specifies CL_MEM_READ_WRITE or CL_MEM_WRITE_ONLY, or if
flags specifies CL_MEM_USE_HOST_PTR or CL_MEM_ALLOC_HOST_PTR or CL_MEM_COPY_HOST_PTR.
• CL_INVALID_VALUE if a 1D image buffer is being created and the buffer object was created with
CL_MEM_HOST_WRITE_ONLY and flags specifies CL_MEM_HOST_READ_ONLY, or if the buffer object was created
with CL_MEM_HOST_READ_ONLY and flags specifies CL_MEM_HOST_WRITE_ONLY, or if the buffer object was
created with CL_MEM_HOST_NO_ACCESS and flags specifies CL_MEM_HOST_READ_ONLY or
CL_MEM_HOST_WRITE_ONLY.
• CL_IMAGE_FORMAT_NOT_SUPPORTED if the image_format is not supported.
• CL_MEM_OBJECT_ALLOCATION_FAILURE if there is a failure to allocate memory for image object.
• CL_INVALID_OPERATION if there are no devices in context that support images (i.e.
CL_DEVICE_IMAGE_SUPPORT (specified in the table of OpenCL Device Queries for clGetDeviceInfo(3clc))
is CL_FALSE).
• 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.
Name
clCreateImage - Creates a 1D image, 1D image buffer, 1D image array, 2D image, 2D image array or 3D image
object.
cl_memclCreateImage(cl_contextcontext,cl_mem_flagsflags,constcl_image_format*image_format,constcl_image_desc*image_desc,void*host_ptr,cl_int*errcode_ret);Notes
1. OpenCL Specification
page 90, section 5.3.1 - Creating Image Objects
The Khronos Group 11/18/2024 CLCREATEIMAGE(3clc)
Parameters
context
A valid OpenCL context on which the image object is to be created.
flags
A bit-field that is used to specify allocation and usage information about the image memory object
being created and is described in the table below.
For all image types except CL_MEM_OBJECT_IMAGE1D_BUFFER, if value specified for flags is 0, the
default is used which is CL_MEM_READ_WRITE.
For CL_MEM_OBJECT_IMAGE1D_BUFFER image type, if the CL_MEM_READ_WRITE, CL_MEM_READ_ONLY or
CL_MEM_WRITE_ONLY values are not specified in flags, they are inherited from the corresponding memory
access qualifers associated with buffer. The CL_MEM_USE_HOST_PTR, CL_MEM_ALLOC_HOST_PTR and
CL_MEM_COPY_HOST_PTR values cannot be specified in flags but are inherited from the corresponding
memory access qualifiers associated with buffer. If CL_MEM_COPY_HOST_PTR is specified in the memory
access qualifier values associated with buffer it does not imply any additional copies when the
sub-buffer is created from buffer. If the CL_MEM_HOST_WRITE_ONLY, CL_MEM_HOST_READ_ONLY or
CL_MEM_HOST_NO_ACCESS values are not specified in flags, they are inherited from the corresponding
memory access qualifiers associated with buffer.
┌────────────────────────┬───────────────────────────────────────┐
│ cl_mem_flags │ Description │
├────────────────────────┼───────────────────────────────────────┤
│ CL_MEM_READ_WRITE │ This flag specifies that the memory │
│ │ object will be read and written by a │
│ │ kernel. This is the default. │
├────────────────────────┼───────────────────────────────────────┤
│ CL_MEM_WRITE_ONLY │ This flags specifies that the memory │
│ │ object will be written but not read │
│ │ by a kernel. │
│ │ │
│ │ Reading from a buffer or image object │
│ │ created with CL_MEM_WRITE_ONLY inside │
│ │ a kernel is undefined. │
│ │ │
│ │ CL_MEM_READ_WRITE and │
│ │ CL_MEM_WRITE_ONLY are mutually │
│ │ exclusive. │
├────────────────────────┼───────────────────────────────────────┤
│ CL_MEM_READ_ONLY │ This flag specifies that the memory │
│ │ object is a read-only memory object │
│ │ when used inside a kernel. │
│ │ │
│ │ Writing to a buffer or image object │
│ │ created with CL_MEM_READ_ONLY inside │
│ │ a kernel is undefined. │
│ │ │
│ │ CL_MEM_READ_WRITE or │
│ │ CL_MEM_WRITE_ONLY and │
│ │ CL_MEM_READ_ONLY are mutually │
│ │ exclusive. │
├────────────────────────┼───────────────────────────────────────┤
│ CL_MEM_USE_HOST_PTR │ This flag is valid only if host_ptr │
│ │ is not NULL. If specified, it │
│ │ indicates that the application wants │
│ │ the OpenCL implementation to use │
│ │ memory referenced by host_ptr as the │
│ │ storage bits for the memory object. │
│ │ │
│ │ OpenCL implementations are allowed to │
│ │ cache the buffer contents pointed to │
│ │ by host_ptr in device memory. This │
│ │ cached copy can be used when kernels │
│ │ are executed on a device. │
│ │ │
│ │ The result of OpenCL commands that │
│ │ operate on multiple buffer objects │
│ │ created with the same host_ptr or │
│ │ overlapping host regions is │
│ │ considered to be undefined. │
│ │ │
│ │ Refer to the dataTypes(3clc) for │
│ │ host_ptr for memory objects (buffer │
│ │ and images) created using │
│ │ CL_MEM_USE_HOST_PTR. │
├────────────────────────┼───────────────────────────────────────┤
│ CL_MEM_ALLOC_HOST_PTR │ This flag specifies that the │
│ │ application wants the OpenCL │
│ │ implementation to allocate memory │
│ │ from host accessible memory. │
│ │ │
│ │ CL_MEM_ALLOC_HOST_PTR and │
│ │ CL_MEM_USE_HOST_PTR are mutually │
│ │ exclusive. │
├────────────────────────┼───────────────────────────────────────┤
│ CL_MEM_COPY_HOST_PTR │ This flag is valid only if host_ptr │
│ │ is not NULL. If specified, it │
│ │ indicates that the application wants │
│ │ the OpenCL implementation to allocate │
│ │ memory for the memory object and copy │
│ │ the data from memory referenced by │
│ │ host_ptr. │
│ │ │
│ │ CL_MEM_COPY_HOST_PTR and │
│ │ CL_MEM_USE_HOST_PTR are mutually │
│ │ exclusive. │
│ │ │
│ │ CL_MEM_COPY_HOST_PTR can be used with │
│ │ CL_MEM_ALLOC_HOST_PTR to initialize │
│ │ the contents of the cl_mem object │
│ │ allocated using host-accessible (e.g. │
│ │ PCIe) memory. │
├────────────────────────┼───────────────────────────────────────┤
│ CL_MEM_HOST_WRITE_ONLY │ This flag specifies that the host │
│ │ will only write to the memory object │
│ │ (using OpenCL APIs that enqueue a │
│ │ write or a map for write). This can │
│ │ be used to optimize write access from │
│ │ the host (e.g. enable write combined │
│ │ allocations for memory objects for │
│ │ devices that communicate with the │
│ │ host over a system bus such as PCIe). │
├────────────────────────┼───────────────────────────────────────┤
│ CL_MEM_HOST_READ_ONLY │ This flag specifies that the host │
│ │ will only read the memory object │
│ │ (using OpenCL APIs that enqueue a │
│ │ read or a map for read). │
│ │ │
│ │ CL_MEM_HOST_WRITE_ONLY and │
│ │ CL_MEM_HOST_READ_ONLY are mutually │
│ │ exclusive. │
├────────────────────────┼───────────────────────────────────────┤
│ CL_MEM_HOST_NO_ACCESS │ This flag specifies that the host │
│ │ will not read or write the memory │
│ │ object. │
│ │ │
│ │ CL_MEM_HOST_WRITE_ONLY or │
│ │ CL_MEM_HOST_READ_ONLY and │
│ │ CL_MEM_HOST_NO_ACCESS are mutually │
│ │ exclusive. │
└────────────────────────┴───────────────────────────────────────┘
image_format
A pointer to a structure that describes format properties of the image to be allocated. See
cl_image_format(3clc) for a detailed description of the image format descriptor.
image_desc
A pointer to a structure that describes type and dimensions of the image to be allocated. See
imageDescriptor(3clc) for more information.
host_ptr
A pointer to the image data that may already be allocated by the application. Refer to table below
for a description of how large the buffer that host_ptr points to must be.
┌──────────────────────────────┬─────────────────────────────────────┐
│ ImageType │ Sizeofbufferthathost_ptr points │
│ │ to │
├──────────────────────────────┼─────────────────────────────────────┤
│ CL_MEM_OBJECT_IMAGE1D │ ≥image_row_pitch │
├──────────────────────────────┼─────────────────────────────────────┤
│ CL_MEM_OBJECT_IMAGE1D_BUFFER │ ≥image_row_pitch │
├──────────────────────────────┼─────────────────────────────────────┤
│ CL_MEM_OBJECT_IMAGE2D │ ≥image_row_pitch*image_height │
├──────────────────────────────┼─────────────────────────────────────┤
│ CL_MEM_OBJECT_IMAGE3D │ ≥image_slice_pitch*image_depth │
├──────────────────────────────┼─────────────────────────────────────┤
│ CL_MEM_OBJECT_IMAGE1D_ARRAY │ ≥image_slice_pitch* │
│ │ image_array_size │
├──────────────────────────────┼─────────────────────────────────────┤
│ CL_MEM_OBJECT_IMAGE2D_ARRAY │ ≥image_slice_pitch* │
│ │ image_array_size │
└──────────────────────────────┴─────────────────────────────────────┘
For a 3D image or 2D image array, the image data specified by host_ptr is stored as a linear sequence
of adjacent 2D image slices or 2D images respectively. Each 2D image is a linear sequence of adjacent
scanlines. Each scanline is a linear sequence of image elements.
For a 2D image, the image data specified by host_ptr is stored as a linear sequence of adjacent
scanlines. Each scanline is a linear sequence of image elements.
For a 1D image array, the image data specified by host_ptr is stored as a linear sequence of adjacent
1D images respectively. Each 1D image or 1D image buffer is a single scanline which is a linear
sequence of adjacent elements.
errcode_ret
Will return an appropriate error code. If errcode_ret is NULL, no error code is returned.
See Also
imageDescriptor(3clc), cl_image_format(3clc), classDiagram(3clc)
Specification
OpenCLSpecification[1]
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