Issues all previously queued opencl commands in a command-queue to the device associated with the command-queue.
cl_int clFlush(cl_command_queue command_queue);
Issues all previously queued OpenCL commands in command_queue to the device associated with command_queue.
clFlush only guarantees that all queued commands to command_queue will eventually be submitted to the appropriate device There is no guarantee that they will be complete after clFlush returns.
Any blocking commands queued in a command-queue and clReleaseCommandQueue(3clc) perform an implicit flush of the command-queue. These blocking commands are clEnqueueReadBuffer(3clc), clEnqueueReadBufferRect(3clc), or clEnqueueReadImage(3clc) with blocking_read set to CL_TRUE; clEnqueueWriteBuffer(3clc), clEnqueueWriteBufferRect(3clc), or clEnqueueWriteImage(3clc) with blocking_write set to CL_TRUE; clEnqueueMapBuffer(3clc) or clEnqueueMapImage(3clc) with blocking_map set to CL_TRUE; or clWaitForEvents(3clc).
To use event objects that refer to commands enqueued in a command-queue as event objects to wait on by commands enqueued in a different command-queue, the application must call a clFlush or any blocking commands that perform an implicit flush of the command-queue where the commands that refer to these event objects are enqueued.
Returns CL_SUCCESS if the function call was executed successfully. Otherwise, it returns one of the following:
CL_INVALID_COMMAND_QUEUE if command_queue is not a valid command-queue.
CL_OUT_OF_HOST_MEMORY if there is a failure to allocate resources required by the OpenCL implementation on the host.
CL_OUT_OF_RESOURCES if there is a failure to allocate resources required by the OpenCL implementation on the device.
\m[blue]OpenCL Specification\m[]\s-2\u[1]\d\s+2
clFinish(3clc)
The Khronos Group
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.
OpenCL Specification
page 193, section 5.13 - Flush and Finish