C Specification

To enqueue a command to fill a buffer object with a pattern of a given pattern size, call the function

cl_int clEnqueueFillBuffer(
    cl_command_queue command_queue,
    cl_mem buffer,
    const void* pattern,
    size_t pattern_size,
    size_t offset,
    size_t size,
    cl_uint num_events_in_wait_list,
    const cl_event* event_wait_list,
    cl_event* event);


  • command_queue refers to the host command-queue in which the fill command will be queued. The OpenCL context associated with command_queue and buffer must be the same.

  • buffer is a valid buffer object.

  • pattern is a pointer to the data pattern of size pattern_size in bytes. pattern will be used to fill a region in buffer starting at offset and is size bytes in size. The data pattern must be a scalar or vector integer or floating-point data type supported by OpenCL as described in Shared Application Scalar Data Types and Supported Application Vector Data Types. For example, if buffer is to be filled with a pattern of float4 values, then pattern will be a pointer to a cl_float4 value and pattern_size will be sizeof(cl_float4). The maximum value of pattern_size is the size of the largest integer or floating-point vector data type supported by the OpenCL device. The memory associated with pattern can be reused or freed after the function returns.

  • offset is the location in bytes of the region being filled in buffer and must be a multiple of pattern_size.

  • size is the size in bytes of region being filled in buffer and must be a multiple of pattern_size.

  • 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 particular 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. clEnqueueBarrierWithWaitList can be used instead. If the event_wait_list and the event arguments are not NULL, the event argument should not refer to an element of the event_wait_list array.


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 buffer is created is ignored by clEnqueueFillBuffer.

clEnqueueFillBuffer 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 buffer 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 buffer is not a valid buffer object.

  • CL_​INVALID_​VALUE if offset or offset + size require accessing elements outside the buffer buffer object respectively.

  • CL_​INVALID_​VALUE if pattern is NULL or if pattern_size is 0 or if pattern_size is not one of { 1, 2, 4, 8, 16, 32, 64, 128 }.

  • CL_​INVALID_​VALUE if offset and size are not a multiple of pattern_size.

  • 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_​MISALIGNED_​SUB_​BUFFER_​OFFSET if buffer is a sub-buffer object and offset specified when the sub-buffer object is created is not aligned to CL_​DEVICE_​MEM_​BASE_​ADDR_​ALIGN value for device associated with queue. This error code is missing before version 1.1.

  • CL_​MEM_​OBJECT_​ALLOCATION_​FAILURE if there is a failure to allocate memory for data store associated with buffer.

  • 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

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 (c) 2014-2020 Khronos Group. This work is licensed under a Creative Commons Attribution 4.0 International License.