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    <title>clEnqueueWriteBuffer</title>
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    <div class="refentry">
      <a id="id-1"></a>
      <div class="titlepage"></div>
      <div xmlns="" class="refnamediv">
        <a xmlns="http://www.w3.org/1999/xhtml" id="clEnqueueWriteBuffer"></a>
        <h1>
            clEnqueueWriteBuffer
        </h1>
        <p>
            Enqueue commands to write to a buffer object from host memory.
        </p>
      </div>
      <div class="refsynopsisdiv">
        <h2></h2>
        <div class="funcsynopsis">
          <table xmlns="" border="0" summary="Function synopsis" cellspacing="0" cellpadding="0">
            <tr valign="bottom">
              <td>
                <code xmlns="http://www.w3.org/1999/xhtml" class="funcdef">
                    <a class="link" href="scalarDataTypes.html" target="pagedisplay">cl_int</a>
 <strong class="fsfunc">clEnqueueWriteBuffer</strong>
                (</code>
                <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="abstractDataTypes.html" target="pagedisplay">cl_command_queue</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">command_queue</var>, </td>
              </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="abstractDataTypes.html" target="pagedisplay">cl_mem</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">buffer</var>, </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="enums.html#cl_bool" target="pagedisplay">cl_bool</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">blocking_write</var>, </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="scalarDataTypes.html" target="pagedisplay">size_t</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">offset</var>, </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="scalarDataTypes.html" target="pagedisplay">size_t</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">size</var>, </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td>const <a xmlns="http://www.w3.org/1999/xhtml" class="link" href="scalarDataTypes.html" target="pagedisplay">void</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">*ptr</var>, </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="scalarDataTypes.html" target="pagedisplay">cl_uint</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">num_events_in_wait_list</var>, </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td>const <a xmlns="http://www.w3.org/1999/xhtml" class="link" href="abstractDataTypes.html" target="pagedisplay">cl_event</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">*event_wait_list</var>, </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="abstractDataTypes.html" target="pagedisplay">cl_event</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">*event</var><code>)</code></td>
            </tr>
          </table>
        </div>
      </div>
      <div class="refsect1">
        <a id="parameters"></a>
        <h2>Parameters</h2>
        <div class="variablelist">
          <dl class="variablelist">
            <dt>
              <span class="term"> <code class="varname"> command_queue </code> </span>
            </dt>
            <dd>
              <p>
                        Is a valid host command-queue in which the write command will be
                        queued. <code class="varname">command_queue</code> and <code class="varname">buffer</code> must
                        be created with the same OpenCL context.
                    </p>
            </dd>
            <dt>
              <span class="term"> <code class="varname"> buffer </code> </span>
            </dt>
            <dd>
              <p>
                        Refers to a valid buffer object.
                    </p>
            </dd>
            <dt>
              <span class="term"> <code class="varname"> blocking_write </code> </span>
            </dt>
            <dd>
              <p>
                      Indicates if the write operations are
                      <code class="varname">blocking</code> or <code class="varname">nonblocking</code>.
                    </p>
              <p>
                      If <code class="varname">blocking_write</code> is <code class="constant">CL_TRUE</code>, the
                      OpenCL implementation copies the data referred to by <code class="varname">ptr</code>
                      and enqueues the write operation in the command-queue. The memory pointed
                      to by <code class="varname">ptr</code> can be reused by the application after the
                      <code class="function">clEnqueueWriteBuffer</code> call returns.
                    </p>
              <p>
                      If <code class="varname">blocking_write</code> is <code class="constant">CL_FALSE</code>,
                      the OpenCL implementation will use <code class="varname">ptr</code> to perform a
                      nonblocking write. As the write is non-blocking the implementation can return
                      immediately. The memory pointed to by <code class="varname">ptr</code> cannot be reused
                      by the application after the call returns. The <code class="varname">event</code>
                      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 <code class="varname">ptr</code> can then be reused by the application.
                    </p>
            </dd>
            <dt>
              <span class="term"> <code class="varname"> offset </code> </span>
            </dt>
            <dd>
              <p>
                        The offset in bytes in the buffer object to write to.
                    </p>
            </dd>
            <dt>
              <span class="term"> <code class="varname"> size </code> </span>
            </dt>
            <dd>
              <p>
                        The size in bytes of data being written.
                    </p>
            </dd>
            <dt>
              <span class="term"> <code class="varname"> ptr </code> </span>
            </dt>
            <dd>
              <p>
                        The pointer to buffer in host memory where data is to be written from.
                    </p>
            </dd>
            <dt>
              <span class="term"> <code class="varname">event_wait_list</code>
                , </span>
              <span class="term">
                    <code class="varname">num_events_in_wait_list</code>
                </span>
            </dt>
            <dd>
              <p>
                      <code class="varname">event_wait_list</code>
                      and <code class="varname">num_events_in_wait_list</code> specify events that
                      need to complete before this particular command can be executed. If
                      <code class="varname">event_wait_list</code> is NULL, then this particular command does
                      not wait on any event to complete. If <code class="varname">event_wait_list</code>
                      is NULL, <code class="varname">num_events_in_wait_list</code> must be 0. If
                      <code class="varname">event_wait_list</code> is not NULL, the list of events
                      pointed to by <code class="varname">event_wait_list</code> must be valid
                      and <code class="varname">num_events_in_wait_list</code> must be greater
                      than 0. The events specified in <code class="varname">event_wait_list</code>
                      act as synchronization points.  The context associated with events in
                      <code class="varname">event_wait_list</code> and <code class="varname">command_queue</code> must
                      be the same.  The memory associated with <code class="varname">event_wait_list</code>
                      can be reused or freed after the function returns.
                    </p>
            </dd>
            <dt>
              <span class="term"> <code class="varname"> event </code> </span>
            </dt>
            <dd>
              <p>
                      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. <code class="varname">event</code> 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.
                      If the <code class="varname">event_wait_list</code> and the <code class="varname">event</code> 
                      arguments are not NULL, the <code class="varname">event</code> argument should not 
                      refer to an element of the <code class="varname">event_wait_list</code> array
                    </p>
            </dd>
          </dl>
        </div>
      </div>
      <div class="refsect1">
        <a id="notes"></a>
        <h2>Notes</h2>
        <p>
          Calling <code class="function">clEnqueueWriteBuffer</code> to update the latest bits
          in a region of the buffer object with the <code class="varname">ptr</code> argument
          value set to <code class="varname">host_ptr</code> + <code class="varname">offset</code>, where
          <code class="varname">host_ptr</code> is a pointer to the memory region specified when the
          buffer object being written is created with <code class="constant">CL_MEM_USE_HOST_PTR</code>,
          must meet the following requirements in order to avoid undefined behavior:
        </p>
        <div class="itemizedlist">
          <ul class="itemizedlist" style="list-style-type: disc; ">
            <li class="listitem" style="list-style-type: disc">
              The host memory region given by <code class="varname">(host_ptr + offset, cb)</code>
              contains the latest bits when the enqueued write command begins execution.
            </li>
            <li class="listitem" style="list-style-type: disc">
              The buffer object or memory objects created from this buffer object are not mapped.
            </li>
            <li class="listitem" style="list-style-type: disc">
              The buffer object or memory objects created from this buffer object are not used
              by any command-queue until the read command has finished execution.
            </li>
          </ul>
        </div>
      </div>
      <div class="refsect1">
        <a id="errors"></a>
        <h2>Errors</h2>
        <p>
          <code class="function">clEnqueueWriteBuffer</code> returns <span class="errorname">CL_SUCCESS</span> if
          the function is executed successfully. Otherwise, it returns one of the following errors:
        </p>
        <div class="itemizedlist">
          <ul class="itemizedlist" style="list-style-type: disc; ">
            <li class="listitem" style="list-style-type: disc"><span class="errorname">CL_INVALID_COMMAND_QUEUE</span> if <code class="varname">command_queue</code>
              is not a valid command-queue.
            </li>
            <li class="listitem" style="list-style-type: disc"><span class="errorname">CL_INVALID_CONTEXT</span> if the context associated with
              <code class="varname">command_queue</code> and <code class="varname">buffer</code> are not the same
              or if the context associated with <code class="varname">command_queue</code> and events in
              <code class="varname">event_wait_list</code> are not the same.
            </li>
            <li class="listitem" style="list-style-type: disc"><span class="errorname">CL_INVALID_MEM_OBJECT</span> if <code class="varname">buffer</code>
                is not a valid buffer object.
            </li>
            <li class="listitem" style="list-style-type: disc"><span class="errorname">CL_INVALID_VALUE</span> if the region being written specified
              by (<code class="varname">offset</code>, <code class="varname">size</code>) is out of bounds or if
              <code class="varname">ptr</code> is a NULL value.
            </li>
            <li class="listitem" style="list-style-type: disc"><span class="errorname">CL_INVALID_EVENT_WAIT_LIST</span>
              if <code class="varname">event_wait_list</code> is NULL and
              <code class="varname">num_events_in_wait_list</code> &gt;
              0, or <code class="varname">event_wait_list</code> is not NULL and
              <code class="varname">num_events_in_wait_list</code> is 0, or if event objects in
              <code class="varname">event_wait_list</code> are not valid events.
            </li>
            <li class="listitem" style="list-style-type: disc"><span class="errorname">CL_MISALIGNED_SUB_BUFFER_OFFSET</span> if
              <code class="varname">buffer</code> is a sub-buffer object and <code class="varname">offset</code>
              specified when the sub-buffer object is created is not aligned to
              <code class="constant">CL_DEVICE_MEM_BASE_ADDR_ALIGN</code> value for device associated
              with <code class="varname">queue</code>.
            </li>
            <li class="listitem" style="list-style-type: disc"><span class="errorname">CL_EXEC_STATUS_ERROR_FOR_EVENTS_IN_WAIT_LIST</span> if the read
              and write operations are blocking and the execution status of any of the events
              in <code class="varname">event_wait_list</code> is a negative integer value.
            </li>
            <li class="listitem" style="list-style-type: disc"><span class="errorname">CL_MEM_OBJECT_ALLOCATION_FAILURE</span> if there is a failure to
              allocate memory for data store associated with <code class="varname">buffer</code>.
            </li>
            <li class="listitem" style="list-style-type: disc"><span class="errorname">CL_INVALID_OPERATION</span> if
              <a class="citerefentry" href="clEnqueueWriteBuffer.html"><span class="citerefentry"><span class="refentrytitle">clEnqueueWriteBuffer</span></span></a>
              is called on <code class="varname">buffer</code> which has been
              created with <code class="constant">CL_MEM_HOST_READ_ONLY</code> or
              <code class="constant">CL_MEM_HOST_NO_ACCESS</code>.
            </li>
            <li class="listitem" style="list-style-type: disc"><span class="errorname">CL_OUT_OF_RESOURCES</span> if there is a failure to allocate
              resources required by the OpenCL implementation on the device.
            </li>
            <li class="listitem" style="list-style-type: disc"><span class="errorname">CL_OUT_OF_HOST_MEMORY</span> if there is a failure to allocate
              resources required by the OpenCL implementation on the host.
            </li>
          </ul>
        </div>
      </div>
      <div class="refsect1">
        <a id="specification"></a>
        <h2>Specification</h2>
        <p>
            <img src="pdficon_small1.gif" />

            <a href="https://www.khronos.org/registry/cl/specs/opencl-2.1.pdf#page=110" target="OpenCL Spec">OpenCL Specification</a>
        </p>
      </div>
      <div class="refsect1">
        <a id="seealso"></a>
        <h2>Also see</h2>
        <p>
            <a class="citerefentry" href="clEnqueueCopyBuffer.html"><span class="citerefentry"><span class="refentrytitle">clEnqueueCopyBuffer</span></span></a>,
            <a class="citerefentry" href="clEnqueueReadBuffer.html"><span class="citerefentry"><span class="refentrytitle">clEnqueueReadBuffer</span></span></a>,
            <a class="citerefentry" href="clEnqueueReadBufferRect.html"><span class="citerefentry"><span class="refentrytitle">clEnqueueReadBufferRect</span></span></a>,
            <a class="citerefentry" href="clEnqueueWriteBufferRect.html"><span class="citerefentry"><span class="refentrytitle">clEnqueueWriteBufferRect</span></span></a>
        </p>
      </div>
      <div xmlns="" class="refsect3" lang="en" xml:lang="en"><a xmlns="http://www.w3.org/1999/xhtml" id="Copyright"></a><h4 xmlns="http://www.w3.org/1999/xhtml"></h4><img xmlns="http://www.w3.org/1999/xhtml" src="KhronosLogo.jpg" /><p xmlns="http://www.w3.org/1999/xhtml"></p>Copyright © 2007-2015 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
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