table of contents
CLCREATEIMAGE(3clc) | OpenCL Manual | CLCREATEIMAGE(3clc) |
NAME¶
clCreateImage - Creates a 1D image, 1D image buffer, 1D image array, 2D image, 2D image array or 3D image object.
¶
cl_mem clCreateImage(cl_context context, cl_mem_flags flags, const cl_image_format *image_format, const cl_image_desc *image_desc, void *host_ptr, cl_int *errcode_ret);
PARAMETERS¶
context
flags
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
image_desc
host_ptr
Image Type | Size of buffer that host_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
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:
SPECIFICATION¶
OpenCL Specification[1]
SEE ALSO¶
imageDescriptor(3clc), cl_image_format(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
01/14/2021 | The Khronos Group |