C Specification

To enqueue a command to copy an image object to a buffer object, call the function

// Provided by CL_VERSION_1_0
cl_int clEnqueueCopyImageToBuffer(
    cl_command_queue command_queue,
    cl_mem src_image,
    cl_mem dst_buffer,
    const size_t* src_origin,
    const size_t* region,
    size_t dst_offset,
    cl_uint num_events_in_wait_list,
    const cl_event* event_wait_list,
    cl_event* event);

Parameters

  • command_queue must be a valid host command-queue. The OpenCL context associated with command_queue, src_image and dst_buffer must be the same.

  • src_image is a valid image object.

  • dst_buffer is a valid buffer object.

  • src_origin defines the (x, y, z) offset in pixels in the 1D, 2D or 3D image, the (x, y) offset and the image index in the 2D image array or the (x) offset and the image index in the 1D image array. If src_image is a 2D image object, src_origin[2] must be 0. If src_image is a 1D image or 1D image buffer object, src_origin[1] and src_origin[2] must be 0. If src_image is a 1D image array object, src_origin[2] must be 0. If src_image is a 1D image array object, src_origin[1] describes the image index in the 1D image array. If src_image is a 2D image array object, src_origin[2] describes the image index in the 2D image array. If src_image is a mipmapped image, the mip level to read is determined from src_origin as described in Specifying Mipmap Levels to Image Operations

  • region defines the (width, height, depth) in pixels of the 1D, 2D or 3D rectangle, the (width, height) in pixels of the 2D rectangle and the number of images of a 2D image array or the (width) in pixels of the 1D rectangle and the number of images of a 1D image array. If src_image is a 2D image object, region[2] must be 1. If src_image is a 1D image or 1D image buffer object, region[1] and region[2] must be 1. If src_image is a 1D image array object, region[2] must be 1. The values in region cannot be 0.

  • dst_offset refers to the offset where to begin copying data into dst_buffer. The size in bytes of the region to be copied referred to as dst_cb is computed as width × height × depth × bytes/image element if src_image is a 3D image object, is computed as width × height × bytes/image element if src_image is a 2D image, is computed as width × height × arraysize × bytes/image element if src_image is a 2D image array object, is computed as width × bytes/image element if src_image is a 1D image or 1D image buffer object and is computed as width × arraysize × bytes/image element if src_image is a 1D image array object.

  • event_wait_list and num_events_in_wait_list specify events that need to complete before this particular command can be executed. If event_wait_list is NULL, then this particular command does not wait on any event to complete. If event_wait_list is NULL, num_events_in_wait_list must be 0. If event_wait_list is not NULL, the list of events pointed to by event_wait_list must be valid and num_events_in_wait_list must be greater than 0. The events specified in event_wait_list act as synchronization points. The context associated with events in event_wait_list and command_queue must be the same. The memory associated with event_wait_list can be reused or freed after the function returns.

  • event returns an event object that identifies this copy command and can be used to query or queue a wait for this command to complete. If event is NULL or the enqueue is unsuccessful, no event will be created and therefore it will not be possible to query the status of this command or to wait for this command to complete. If event_wait_list and event are not NULL, event must not refer to an element of the event_wait_list array.

Description

The usage information which indicates whether the memory object can be read or written by a kernel and/or the host and is given by the cl_mem_flags argument value specified when src_image or dst_buffer is created is ignored by clEnqueueCopyImageToBuffer.

clEnqueueCopyImageToBuffer returns CL_SUCCESS if the function is executed successfully. Otherwise, it returns one of the following errors:

  • CL_INVALID_COMMAND_QUEUE

    • if command_queue is not a valid host command-queue

  • CL_INVALID_CONTEXT

    • if the context associated with command_queue and src_image are not the same

    • if the context associated with command_queue and dst_buffer are not the same

    • if the context associated with command_queue and events in event_wait_list are not the same

  • CL_INVALID_MEM_OBJECT

    • if src_image is not a valid image object

    • if dst_buffer is not a valid buffer object

    • if src_image is a 1D image buffer object created from dst_buffer

  • CL_INVALID_VALUE

    • if src_origin is NULL

    • if region is NULL

    • if the 1D, 2D or 3D rectangular region specified by src_origin and region is out of bounds of src_image

    • if the region specified by dst_offset and the computed dst_cb is out of bounds of dst_buffer

    • if values in src_origin and region do not follow the rules described in the argument description for src_origin and region

  • CL_INVALID_MIP_LEVEL

    • if the cl_khr_mipmap_image extension is supported and the mip level specified in src_origin is not a valid level for src_image

  • CL_INVALID_EVENT_WAIT_LIST

    • if event_wait_list is NULL and num_events_in_wait_list is greater than zero

    • if event_wait_list is not NULL and num_events_in_wait_list is zero

    • if event objects in event_wait_list are not valid events

  • CL_MISALIGNED_SUB_BUFFER_OFFSET

    • if dst_buffer is a sub-buffer object and the offset specified when the sub-buffer object was created is not aligned to the CL_DEVICE_MEM_BASE_ADDR_ALIGN value for the device associated with command_queue. This error code is missing before version 1.1.

  • CL_INVALID_IMAGE_SIZE

    • if the dimensions for src_image, such as the image width or image height, are not supported by the device associated with command_queue

  • CL_IMAGE_FORMAT_NOT_SUPPORTED

    • if the format for src_image, such as the image channel order or image channel data type, are not supported by the device associated with command_queue

  • CL_MEM_OBJECT_ALLOCATION_FAILURE

    • if there is a failure to allocate memory for the data store associated with src_image

    • if there is a failure to allocate memory for the data store associated with dst_buffer

  • CL_INVALID_OPERATION

    • if the device associated with command_queue does not support images (the query for CL_DEVICE_IMAGE_SUPPORT returns CL_FALSE)

    • if dst_buffer was created with CL_MEM_IMMUTABLE_EXT

  • 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

See Also

CL_VERSION_1_0, cl_command_queue, cl_event, cl_mem, cl_uint

Document Notes

For more information, see the OpenCL Specification

This page is extracted from the OpenCL Specification. Fixes and changes should be made to the Specification, not directly.

Copyright

Copyright 2014-2026 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0