sdk/2.1/docs/man/preprocessorDirectives.xml

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<refentry>
    <refentryinfo>
        <keywordset>
            <keyword>Preprocessor Directives and Macros</keyword>
        </keywordset>
    </refentryinfo>

    <refmeta>
        <refentrytitle>Preprocessor Directives and Macros</refentrytitle>

        <refmiscinfo>
            <copyright>
                <year>2007-2013</year>
                <holder>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.</holder>
            </copyright>
        </refmiscinfo>
        <manvolnum>3</manvolnum>
    </refmeta>

<!-- ================================ SYNOPSIS -->

    <refnamediv id="PreprocessorDirectivesandMacros">
        <refname>Preprocessor Directives and Macros</refname>

        <refpurpose>
            Preprocessor Directives and Macros.
        </refpurpose>
    </refnamediv>

    <!-- ALTERNATIVE SYNTAX SYNOPSIS (NON-FUNCTION) -->
    <refsect2 id="synopsis">
        <title>
        </title>

        <informaltable frame="none">
            <tgroup cols="1" align="left" colsep="0" rowsep="0">
                <colspec colname="col1" colnum="1" />
                <tbody>
                    <row>
                        <entry>
# <function>pragma</function> <varname>pp-tokens</varname><subscript>opt</subscript> <emphasis>new-line</emphasis>
                        </entry>
                    </row>
                </tbody>
            </tgroup>
        </informaltable>
    </refsect2>

<!-- ================================ DESCRIPTION  -->

    <refsect1 id="description"><title>Description</title>
        <para>
          The preprocessing directives defined by the C99 specification are supported.
        </para>

        <para>
          A <function># pragma</function> directive where the preprocessing token
          <constant>OPENCL</constant> (used instead of <constant>STDC</constant>) does not
          immediately follow <function>pragma</function> in the directive (prior to any macro
          replacement) causes the implementation to behave in an implementation-defined manner. The
          behavior might cause translation to fail or cause the translator or the resulting
          program to behave in a non-conforming manner. Any such <function>pragma</function>
          that is not recognized by the implementation is ignored. If the preprocessing token
          <constant>OPENCL</constant> does immediately follow <function>pragma</function> in the
          directive (prior to any macro replacement), then no macro replacement is performed on
          the directive, and the directive shall have one of the following forms whose meanings
          are described elsewhere:
        </para>

        <para>
<literallayout><constant>          #pragma OPENCL <citerefentry><refentrytitle>FP_CONTRACT</refentrytitle></citerefentry> <replaceable>on-off-switch</replaceable>
               <replaceable>on-off-switch</replaceable>: one of ON OFF DEFAULT
          #pragma OPENCL <citerefentry><refentrytitle>EXTENSION</refentrytitle></citerefentry> <varname>extensionname : behavior</varname>
          #pragma OPENCL <citerefentry><refentrytitle>EXTENSION</refentrytitle></citerefentry> all : <varname>behavior</varname></constant></literallayout>
        </para>

        <para>
          The following predefined macro names are available.
        </para>

        <itemizedlist mark="disc">
            <listitem>
                 <code>__FILE__</code> The presumed name of the current 
                 source file (a character string literal).
            </listitem>

            <listitem>
                 <code>__LINE__</code> The presumed line number (within the current source file)
                 of the current source line (an integer constant).
            </listitem>

            <listitem>
                 <code>__OPENCL_VERSION__</code> substitutes an integer reflecting the version
                 number of the OpenCL supported by the OpenCL device. The version of OpenCL
                 described in this document will have <code>__OPENCL_VERSION__</code> substitute
                 the integer 200.
            </listitem>

            <listitem>
                <code>CL_VERSION_1_0</code> substitutes the integer 100 reflecting the OpenCL 1.0 version.
            </listitem>

            <listitem>
                <code>CL_VERSION_1_1</code> substitutes the integer 110 reflecting the OpenCL 1.1 version.
            </listitem>

            <listitem>
                <code>CL_VERSION_1_2</code> substitutes the integer 120 reflecting the OpenCL 1.2 version.
            </listitem>

            <listitem>
                <code>CL_VERSION_2_0</code> substitutes the integer 200 reflecting the OpenCL 2.0 version.
            </listitem>

            <listitem>
                <code>__OPENCL_C_VERSION__</code> substitutes an integer reflecting
                the OpenCL C version specified by the <code>-cl-std</code> build option  to
                <citerefentry><refentrytitle>clBuildProgram</refentrytitle></citerefentry> or
                <citerefentry><refentrytitle>clCompileProgram</refentrytitle></citerefentry>. 
                If the <code>-cl-std</code>
                build option is not specified, the highest OpenCL C 1.x 
                language version supported by each device is used 
                as the version of OpenCL C when compiling 
                the program for each device. The version of OpenCL C 
                described in this document will have 
                <code>__OPENCL_C_VERSION__</code> substitute the integer 200 
                if <code>–cl-std=CL2.0</code> is specified.
            </listitem>

            <listitem>
                <code>__ENDIAN_LITTLE__</code> is used to determine if the OpenCL device is a
                little endian architecture or a big endian architecture (an integer constant
                of 1 if device is little endian and is undefined otherwise). Also refer to
                <constant>CL_DEVICE_ENDIAN_LITTLE</constant> specified in the table of OpenCL
                Device Queries for 
                <citerefentry><refentrytitle>clGetDeviceInfo</refentrytitle></citerefentry>.
            </listitem>

            <listitem>
                <code>__kernel_exec(X, type<replaceable>n</replaceable>)</code> (and
                <code>kernel_exec(X, type<replaceable>n</replaceable>))</code> is defined as
                follows:

                <para>
<literallayout>     <code>__kernel __attribute__((work_group_size_hint(X, 1, 1)))</code> \
              <code>__attribute__((vec_type_hint(type<replaceable>n</replaceable>)))</code></literallayout>
                </para>
            </listitem>

            <listitem>
                <code>__IMAGE_SUPPORT__</code> is used to determine if the OpenCL device supports
                images. This is an integer constant of 1 if images are supported and is undefined
                otherwise. Also refer to <constant>CL_DEVICE_IMAGE_SUPPORT</constant>
                specified in the table of OpenCL Device Queries for
                <citerefentry><refentrytitle>clGetDeviceInfo</refentrytitle></citerefentry><!--table
                4.3-->.
            </listitem>

            <listitem>
                <code>__FAST_RELAXED_MATH__</code> is used to determine if the
                cl-fast-relaxed-math optimization option is specified in build options given
                to  <citerefentry><refentrytitle>clBuildProgram</refentrytitle></citerefentry> or
                <citerefentry><refentrytitle>clCompileProgram</refentrytitle></citerefentry>. 
                This is an integer constant of 1 if the cl-fast-relaxed-math build option 
                is specified and is undefined otherwise.
             </listitem>

            <listitem>
                The <code>NULL</code> macro expands to a null pointer 
                constant. An integer constant expression with the 
                value 0, or such an expression cast to type 
                <code>void *</code> is called a null pointer constant.
            </listitem>

            <listitem>
                The macro names defined by the C99 specification but not currently supported
                by OpenCL are reserved for future use.
            </listitem>

            <listitem>
                The predefined identifier <code>__func__</code> is available.
            </listitem>
        </itemizedlist>
    </refsect1>

<!-- ================================ EXAMPLE  -->
<!-- DO NOT DELETE IN CASE AN EXAMPLE IS ADDED IN THE FUTURE -->
<!--
    <refsect2 id="example1">
        <title>
            Example
        </title>

        <informaltable frame="none">
            <tgroup cols="1" align="left" colsep="0" rowsep="0">
                <colspec colname="col1" colnum="1" />
                <tbody>
                    <row>
                        <entry>
                            Example goes here - it will be set in "code" type with white space preserved.
                        </entry>
                    </row>
                </tbody>
            </tgroup>
        </informaltable>
    </refsect2>
-->

<!-- ================================ SPECIFICATION  -->
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    <refsect1 id="specification"><title>Specification</title>
        <para>
            <imageobject>
                <imagedata fileref="pdficon_small1.gif" format="gif" />
            </imageobject>

            <olink uri="preprocessorDirectives">OpenCL Specification</olink>
        </para>
    </refsect1>

<!-- ================================ ALSO SEE  -->

    <refsect1 id="seealso"><title>Also see</title>
        <para>
            <citerefentry href="mathConstants"><refentrytitle>Symbolic Math Constants</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>clBuildProgram</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>FP_CONTRACT</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>EXTENSION</refentrytitle></citerefentry>
        </para>
    </refsect1>

<!-- ============================== COPYRIGHT -->
<!-- Content included from copyright.inc.xsl -->

    <refsect3 id="Copyright"><title></title>
        <imageobject>
                <imagedata fileref="KhronosLogo.jpg" format="jpg" />
        </imageobject>
        <para />
    </refsect3>

 <!-- 28-Oct-2015, C lang ver 2.0 rev 30 -->
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