NAME¶
clEnqueueWriteImage - Enqueues a command to write to an image or
image array object from host memory.
cl_int
clEnqueueWriteImage(cl_command_queue command_queue,
cl_mem image,
cl_bool blocking_write,
const size_t *origin,
const size_t *region,
size_t input_row_pitch,
size_t input_slice_pitch,
const void * ptr,
cl_uint num_events_in_wait_list,
const cl_event *event_wait_list,
cl_event *event);
PARAMETERS¶
command_queue
Refers to the command-queue in which the write command
will be queued. command_queue and image must be created with the
same OpenCL context.
image
Refers to a valid image or image array object.
blocking_write
Indicates if the write operation is
blocking or
non-blocking.
If blocking_write is CL_TRUE the OpenCL
implementation copies the data referred to by ptr and enqueues the
write command in the command-queue. The memory pointed to by ptr can
be reused by the application after the clEnqueueWriteImage call
returns.
If blocking_write is CL_FALSE the OpenCL
implementation will use ptr to perform a nonblocking write. As the
write is non-blocking the implementation can return immediately. The memory
pointed to by ptr cannot be reused by the application after the call
returns. The event argument returns an event object which can be used
to query the execution status of the write command. When the write command
has completed, the memory pointed to by ptr can then be reused by the
application.
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 image
array or the (x) offset and the image index in the 1D image array. If
image is a 2D image object, origin[2] must be 0. If image
is a 1D image or 1D image buffer object, origin[1] and origin[2]
must be 0. If image is a 1D image array object, origin[2] must
be 0. If image is a 1D image array object, origin[1] describes
the image index in the 1D image array. If image is a 2D image array
object, origin[2] describes the image index in the 2D image
array.
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
image is a 2D image object, region[2] must be 1. If image
is a 1D image or 1D image buffer object, region[1] and region[2]
must be 1. If image is a 1D image array object, region[2] must be
1.
input_row_pitch
The length of each row in bytes. This value must be
greater than or equal to the element size in bytes * width. If
row_pitch is set to 0, the appropriate row pitch is calculated based on
the size of each element in bytes multiplied by width.
input_slice_pitch
Size in bytes of the 2D slice of the 3D region of a 3D
image or each image of a 1D or 2D image array being written. This must be 0 if
image is a 1D or 2D image. This value must be greater than or equal to
row_pitch * height. If slice_pitch is set to 0, the
appropriate slice pitch is calculated based on the row_pitch *
height.
ptr
The pointer to a buffer in host memory where image data
is to be written to.
event_wait_list , 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 particular
write command and can be used to query or queue a wait for this particular
command to complete. event can be NULL in which case it will not be
possible for the application to query the status of this command or queue a
wait for this command to complete.
NOTES¶
Calling clEnqueueWriteImage to update the latest bits in a
region of the image with the ptr argument value set to
host_ptr + (origin[2] * image slice pitch +
origin[1] * image row pitch + origin[0] * bytes per
pixel), where host_ptr is a pointer to the memory region
specified when the image being written is created with
CL_MEM_USE_HOST_PTR, must meet the following requirements in order to
avoid undefined behavior:
• The host memory region being written contains
the latest bits when the enqueued write command begins execution.
• The input_row_pitch and
input_slice_pitch argument values in clEnqueueWriteImage must be
set to the image row pitch and slice pitch.
• The image object is not mapped.
• The image object is not used by any
command-queue until the write command has finished execution.
ERRORS¶
clEnqueueWriteImage return 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 command-queue.
•CL_INVALID_CONTEXT if the context associated with
command_queue and image are not the same or if the context
associated with command_queue and events in event_wait_list are
not the same.
•CL_INVALID_MEM_OBJECT if image is not a
valid image object.
•CL_INVALID_VALUE if the region being written
specified by origin and region is out of bounds or if ptr
is a NULL value.
•CL_INVALID_VALUE if values in origin and
region do not follow rules described in the argument description for
origin and region.
•CL_INVALID_EVENT_WAIT_LIST if
event_wait_list is NULL and num_events_in_wait_list > 0, or
event_wait_list is not NULL and num_events_in_wait_list is 0, or
if event objects in event_wait_list are not valid events.
•CL_INVALID_IMAGE_SIZE if image dimensions (image
width, height, specified or compute row and/or slice pitch) for image
are not supported by device associated with queue.
•CL_INVALID_IMAGE_FORMAT if image format (image
channel order and data type) for image are not supported by device
associated with queue.
•CL_MEM_OBJECT_ALLOCATION_FAILURE if there is a
failure to allocate memory for data store associated with image.
•CL_INVALID_OPERATION if the device associated
with command_queue does not support images (i.e.
CL_DEVICE_IMAGE_SUPPORT specified the table of allowed values for
param_name for clGetDeviceInfo(3clc) is CL_FALSE).
•CL_INVALID_OPERATION if
clEnqueueWriteImage is called on image which has been created
with CL_MEM_HOST_WRITE_ONLY or CL_MEM_HOST_NO_ACCESS.
•CL_EXEC_STATUS_ERROR_FOR_EVENTS_IN_WAIT_LIST if
the write operations are blocking and the execution status of any of the
events in event_wait_list is a negative integer value.
•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.
SPECIFICATION¶
OpenCL Specification[1]
SEE ALSO¶
clEnqueueReadImage(3clc),
clEnqueueCopyImage(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
page 99, section 5.3.3 - Reading, Writing and Copying
Image Objects
