354 lines
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HTML
354 lines
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<!-- Copyright (C) 1999-2016 Free Software Foundation, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3 or
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any later version published by the Free Software Foundation; with the
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Invariant Sections being "Funding Free Software", the Front-Cover
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Texts being (a) (see below), and with the Back-Cover Texts being (b)
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(see below). A copy of the license is included in the section entitled
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"GNU Free Documentation License".
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(a) The FSF's Front-Cover Text is:
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A GNU Manual
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(b) The FSF's Back-Cover Text is:
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You have freedom to copy and modify this GNU Manual, like GNU
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funds for GNU development. -->
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<!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ -->
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<head>
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<title>The GNU Fortran Compiler: Preprocessing Options</title>
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<meta name="description" content="The GNU Fortran Compiler: Preprocessing Options">
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<meta name="keywords" content="The GNU Fortran Compiler: Preprocessing Options">
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<link href="index.html#Top" rel="start" title="Top">
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<link href="Option-Index.html#Option-Index" rel="index" title="Option Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="Invoking-GNU-Fortran.html#Invoking-GNU-Fortran" rel="up" title="Invoking GNU Fortran">
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<link href="Error-and-Warning-Options.html#Error-and-Warning-Options" rel="next" title="Error and Warning Options">
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<link href="Fortran-Dialect-Options.html#Fortran-Dialect-Options" rel="prev" title="Fortran Dialect Options">
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</head>
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<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
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<a name="Preprocessing-Options"></a>
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<div class="header">
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<p>
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Next: <a href="Error-and-Warning-Options.html#Error-and-Warning-Options" accesskey="n" rel="next">Error and Warning Options</a>, Previous: <a href="Fortran-Dialect-Options.html#Fortran-Dialect-Options" accesskey="p" rel="prev">Fortran Dialect Options</a>, Up: <a href="Invoking-GNU-Fortran.html#Invoking-GNU-Fortran" accesskey="u" rel="up">Invoking GNU Fortran</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<a name="Enable-and-customize-preprocessing"></a>
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<h3 class="section">2.3 Enable and customize preprocessing</h3>
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<a name="index-preprocessor"></a>
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<a name="index-options_002c-preprocessor"></a>
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<a name="index-CPP-1"></a>
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<p>Preprocessor related options. See section
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<a href="Preprocessing-and-conditional-compilation.html#Preprocessing-and-conditional-compilation">Preprocessing and conditional compilation</a> for more detailed
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information on preprocessing in <code>gfortran</code>.
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</p>
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<dl compact="compact">
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<dt><code>-cpp</code></dt>
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<dt><code>-nocpp</code></dt>
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<dd><a name="index-cpp"></a>
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<a name="index-fpp"></a>
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<a name="index-preprocessor_002c-enable"></a>
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<a name="index-preprocessor_002c-disable"></a>
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<p>Enable preprocessing. The preprocessor is automatically invoked if
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the file extension is <samp>.fpp</samp>, <samp>.FPP</samp>, <samp>.F</samp>, <samp>.FOR</samp>,
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<samp>.FTN</samp>, <samp>.F90</samp>, <samp>.F95</samp>, <samp>.F03</samp> or <samp>.F08</samp>. Use
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this option to manually enable preprocessing of any kind of Fortran file.
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</p>
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<p>To disable preprocessing of files with any of the above listed extensions,
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use the negative form: <samp>-nocpp</samp>.
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</p>
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<p>The preprocessor is run in traditional mode. Any restrictions of the
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file-format, especially the limits on line length, apply for
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preprocessed output as well, so it might be advisable to use the
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<samp>-ffree-line-length-none</samp> or <samp>-ffixed-line-length-none</samp>
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options.
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</p>
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</dd>
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<dt><code>-dM</code></dt>
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<dd><a name="index-dM"></a>
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<a name="index-preprocessor_002c-debugging"></a>
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<a name="index-debugging_002c-preprocessor"></a>
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<p>Instead of the normal output, generate a list of <code>'#define'</code>
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directives for all the macros defined during the execution of the
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preprocessor, including predefined macros. This gives you a way
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of finding out what is predefined in your version of the preprocessor.
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Assuming you have no file <samp>foo.f90</samp>, the command
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</p><div class="smallexample">
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<pre class="smallexample"> touch foo.f90; gfortran -cpp -E -dM foo.f90
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</pre></div>
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<p>will show all the predefined macros.
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</p>
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</dd>
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<dt><code>-dD</code></dt>
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<dd><a name="index-dD"></a>
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<a name="index-preprocessor_002c-debugging-1"></a>
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<a name="index-debugging_002c-preprocessor-1"></a>
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<p>Like <samp>-dM</samp> except in two respects: it does not include the
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predefined macros, and it outputs both the <code>#define</code> directives
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and the result of preprocessing. Both kinds of output go to the
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standard output file.
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</p>
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</dd>
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<dt><code>-dN</code></dt>
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<dd><a name="index-dN"></a>
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<a name="index-preprocessor_002c-debugging-2"></a>
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<a name="index-debugging_002c-preprocessor-2"></a>
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<p>Like <samp>-dD</samp>, but emit only the macro names, not their expansions.
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</p>
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</dd>
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<dt><code>-dU</code></dt>
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<dd><a name="index-dU"></a>
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<a name="index-preprocessor_002c-debugging-3"></a>
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<a name="index-debugging_002c-preprocessor-3"></a>
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<p>Like <samp>dD</samp> except that only macros that are expanded, or whose
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definedness is tested in preprocessor directives, are output; the
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output is delayed until the use or test of the macro; and <code>'#undef'</code>
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directives are also output for macros tested but undefined at the time.
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</p>
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</dd>
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<dt><code>-dI</code></dt>
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<dd><a name="index-dI"></a>
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<a name="index-preprocessor_002c-debugging-4"></a>
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<a name="index-debugging_002c-preprocessor-4"></a>
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<p>Output <code>'#include'</code> directives in addition to the result
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of preprocessing.
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</p>
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</dd>
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<dt><code>-fworking-directory</code></dt>
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<dd><a name="index-fworking_002ddirectory"></a>
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<a name="index-preprocessor_002c-working-directory"></a>
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<p>Enable generation of linemarkers in the preprocessor output that will
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let the compiler know the current working directory at the time of
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preprocessing. When this option is enabled, the preprocessor will emit,
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after the initial linemarker, a second linemarker with the current
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working directory followed by two slashes. GCC will use this directory,
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when it is present in the preprocessed input, as the directory emitted
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as the current working directory in some debugging information formats.
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This option is implicitly enabled if debugging information is enabled,
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but this can be inhibited with the negated form
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<samp>-fno-working-directory</samp>. If the <samp>-P</samp> flag is present
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in the command line, this option has no effect, since no <code>#line</code>
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directives are emitted whatsoever.
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</p>
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</dd>
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<dt><code>-idirafter <var>dir</var></code></dt>
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<dd><a name="index-idirafter-dir"></a>
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<a name="index-preprocessing_002c-include-path"></a>
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<p>Search <var>dir</var> for include files, but do it after all directories
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specified with <samp>-I</samp> and the standard system directories have
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been exhausted. <var>dir</var> is treated as a system include directory.
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If dir begins with <code>=</code>, then the <code>=</code> will be replaced by
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the sysroot prefix; see <samp>--sysroot</samp> and <samp>-isysroot</samp>.
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</p>
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</dd>
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<dt><code>-imultilib <var>dir</var></code></dt>
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<dd><a name="index-imultilib-dir"></a>
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<a name="index-preprocessing_002c-include-path-1"></a>
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<p>Use <var>dir</var> as a subdirectory of the directory containing target-specific
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C++ headers.
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</p>
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</dd>
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<dt><code>-iprefix <var>prefix</var></code></dt>
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<dd><a name="index-iprefix-prefix"></a>
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<a name="index-preprocessing_002c-include-path-2"></a>
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<p>Specify <var>prefix</var> as the prefix for subsequent <samp>-iwithprefix</samp>
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options. If the <var>prefix</var> represents a directory, you should include
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the final <code>'/'</code>.
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</p>
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</dd>
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<dt><code>-isysroot <var>dir</var></code></dt>
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<dd><a name="index-isysroot-dir"></a>
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<a name="index-preprocessing_002c-include-path-3"></a>
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<p>This option is like the <samp>--sysroot</samp> option, but applies only to
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header files. See the <samp>--sysroot</samp> option for more information.
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</p>
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</dd>
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<dt><code>-iquote <var>dir</var></code></dt>
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<dd><a name="index-iquote-dir"></a>
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<a name="index-preprocessing_002c-include-path-4"></a>
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<p>Search <var>dir</var> only for header files requested with <code>#include "file"</code>;
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they are not searched for <code>#include <file></code>, before all directories
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specified by <samp>-I</samp> and before the standard system directories. If
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<var>dir</var> begins with <code>=</code>, then the <code>=</code> will be replaced by the
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sysroot prefix; see <samp>--sysroot</samp> and <samp>-isysroot</samp>.
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</p>
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</dd>
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<dt><code>-isystem <var>dir</var></code></dt>
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<dd><a name="index-isystem-dir"></a>
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<a name="index-preprocessing_002c-include-path-5"></a>
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<p>Search <var>dir</var> for header files, after all directories specified by
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<samp>-I</samp> but before the standard system directories. Mark it as a
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system directory, so that it gets the same special treatment as is
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applied to the standard system directories. If <var>dir</var> begins with
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<code>=</code>, then the <code>=</code> will be replaced by the sysroot prefix;
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see <samp>--sysroot</samp> and <samp>-isysroot</samp>.
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</p>
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</dd>
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<dt><code>-nostdinc</code></dt>
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<dd><a name="index-nostdinc"></a>
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<p>Do not search the standard system directories for header files. Only
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the directories you have specified with <samp>-I</samp> options (and the
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directory of the current file, if appropriate) are searched.
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</p>
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</dd>
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<dt><code>-undef</code></dt>
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<dd><a name="index-undef"></a>
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<p>Do not predefine any system-specific or GCC-specific macros.
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The standard predefined macros remain defined.
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</p>
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</dd>
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<dt><code>-A<var>predicate</var>=<var>answer</var></code></dt>
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<dd><a name="index-Apredicate_003danswer"></a>
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<a name="index-preprocessing_002c-assertion"></a>
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<p>Make an assertion with the predicate <var>predicate</var> and answer <var>answer</var>.
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This form is preferred to the older form -A predicate(answer), which is still
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supported, because it does not use shell special characters.
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</p>
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</dd>
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<dt><code>-A-<var>predicate</var>=<var>answer</var></code></dt>
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<dd><a name="index-A_002dpredicate_003danswer"></a>
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<a name="index-preprocessing_002c-assertion-1"></a>
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<p>Cancel an assertion with the predicate <var>predicate</var> and answer <var>answer</var>.
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</p>
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</dd>
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<dt><code>-C</code></dt>
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<dd><a name="index-C"></a>
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<a name="index-preprocessing_002c-keep-comments"></a>
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<p>Do not discard comments. All comments are passed through to the output
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file, except for comments in processed directives, which are deleted
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along with the directive.
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</p>
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<p>You should be prepared for side effects when using <samp>-C</samp>; it causes
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the preprocessor to treat comments as tokens in their own right. For example,
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comments appearing at the start of what would be a directive line have the
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effect of turning that line into an ordinary source line, since the first
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token on the line is no longer a <code>'#'</code>.
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</p>
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||
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<p>Warning: this currently handles C-Style comments only. The preprocessor
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does not yet recognize Fortran-style comments.
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</p>
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||
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</dd>
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<dt><code>-CC</code></dt>
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<dd><a name="index-CC"></a>
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<a name="index-preprocessing_002c-keep-comments-1"></a>
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<p>Do not discard comments, including during macro expansion. This is like
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<samp>-C</samp>, except that comments contained within macros are also passed
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through to the output file where the macro is expanded.
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</p>
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<p>In addition to the side-effects of the <samp>-C</samp> option, the <samp>-CC</samp>
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option causes all C++-style comments inside a macro to be converted to C-style
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comments. This is to prevent later use of that macro from inadvertently
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commenting out the remainder of the source line. The <samp>-CC</samp> option
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is generally used to support lint comments.
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</p>
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<p>Warning: this currently handles C- and C++-Style comments only. The
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preprocessor does not yet recognize Fortran-style comments.
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</p>
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</dd>
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<dt><code>-D<var>name</var></code></dt>
|
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<dd><a name="index-Dname"></a>
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<a name="index-preprocessing_002c-define-macros"></a>
|
||
|
|
<p>Predefine name as a macro, with definition <code>1</code>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-D<var>name</var>=<var>definition</var></code></dt>
|
||
|
|
<dd><a name="index-Dname_003ddefinition"></a>
|
||
|
|
<a name="index-preprocessing_002c-define-macros-1"></a>
|
||
|
|
<p>The contents of <var>definition</var> are tokenized and processed as if they
|
||
|
|
appeared during translation phase three in a <code>'#define'</code> directive.
|
||
|
|
In particular, the definition will be truncated by embedded newline
|
||
|
|
characters.
|
||
|
|
</p>
|
||
|
|
<p>If you are invoking the preprocessor from a shell or shell-like program
|
||
|
|
you may need to use the shell’s quoting syntax to protect characters such
|
||
|
|
as spaces that have a meaning in the shell syntax.
|
||
|
|
</p>
|
||
|
|
<p>If you wish to define a function-like macro on the command line, write
|
||
|
|
its argument list with surrounding parentheses before the equals sign
|
||
|
|
(if any). Parentheses are meaningful to most shells, so you will need
|
||
|
|
to quote the option. With sh and csh, <code>-D'name(args...)=definition'</code>
|
||
|
|
works.
|
||
|
|
</p>
|
||
|
|
<p><samp>-D</samp> and <samp>-U</samp> options are processed in the order they are
|
||
|
|
given on the command line. All -imacros file and -include file options
|
||
|
|
are processed after all -D and -U options.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-H</code></dt>
|
||
|
|
<dd><a name="index-H"></a>
|
||
|
|
<p>Print the name of each header file used, in addition to other normal
|
||
|
|
activities. Each name is indented to show how deep in the <code>'#include'</code>
|
||
|
|
stack it is.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-P</code></dt>
|
||
|
|
<dd><a name="index-P"></a>
|
||
|
|
<a name="index-preprocessing_002c-no-linemarkers"></a>
|
||
|
|
<p>Inhibit generation of linemarkers in the output from the preprocessor.
|
||
|
|
This might be useful when running the preprocessor on something that
|
||
|
|
is not C code, and will be sent to a program which might be confused
|
||
|
|
by the linemarkers.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-U<var>name</var></code></dt>
|
||
|
|
<dd><a name="index-Uname"></a>
|
||
|
|
<a name="index-preprocessing_002c-undefine-macros"></a>
|
||
|
|
<p>Cancel any previous definition of <var>name</var>, either built in or provided
|
||
|
|
with a <samp>-D</samp> option.
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
|
||
|
|
<hr>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Next: <a href="Error-and-Warning-Options.html#Error-and-Warning-Options" accesskey="n" rel="next">Error and Warning Options</a>, Previous: <a href="Fortran-Dialect-Options.html#Fortran-Dialect-Options" accesskey="p" rel="prev">Fortran Dialect Options</a>, Up: <a href="Invoking-GNU-Fortran.html#Invoking-GNU-Fortran" accesskey="u" rel="up">Invoking GNU Fortran</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|