583 lines
23 KiB
HTML
583 lines
23 KiB
HTML
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||
|
|
<html>
|
||
|
|
<!-- Copyright (C) 1988-2016 Free Software Foundation, Inc.
|
||
|
|
|
||
|
|
Permission is granted to copy, distribute and/or modify this document
|
||
|
|
under the terms of the GNU Free Documentation License, Version 1.3 or
|
||
|
|
any later version published by the Free Software Foundation; with the
|
||
|
|
Invariant Sections being "Funding Free Software", the Front-Cover
|
||
|
|
Texts being (a) (see below), and with the Back-Cover Texts being (b)
|
||
|
|
(see below). A copy of the license is included in the section entitled
|
||
|
|
"GNU Free Documentation License".
|
||
|
|
|
||
|
|
(a) The FSF's Front-Cover Text is:
|
||
|
|
|
||
|
|
A GNU Manual
|
||
|
|
|
||
|
|
(b) The FSF's Back-Cover Text is:
|
||
|
|
|
||
|
|
You have freedom to copy and modify this GNU Manual, like GNU
|
||
|
|
software. Copies published by the Free Software Foundation raise
|
||
|
|
funds for GNU development. -->
|
||
|
|
<!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ -->
|
||
|
|
<head>
|
||
|
|
<title>Using the GNU Compiler Collection (GCC): Overall Options</title>
|
||
|
|
|
||
|
|
<meta name="description" content="Using the GNU Compiler Collection (GCC): Overall Options">
|
||
|
|
<meta name="keywords" content="Using the GNU Compiler Collection (GCC): Overall Options">
|
||
|
|
<meta name="resource-type" content="document">
|
||
|
|
<meta name="distribution" content="global">
|
||
|
|
<meta name="Generator" content="makeinfo">
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
||
|
|
<link href="index.html#Top" rel="start" title="Top">
|
||
|
|
<link href="Option-Index.html#Option-Index" rel="index" title="Option Index">
|
||
|
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
||
|
|
<link href="Invoking-GCC.html#Invoking-GCC" rel="up" title="Invoking GCC">
|
||
|
|
<link href="Invoking-G_002b_002b.html#Invoking-G_002b_002b" rel="next" title="Invoking G++">
|
||
|
|
<link href="Option-Summary.html#Option-Summary" rel="prev" title="Option Summary">
|
||
|
|
<style type="text/css">
|
||
|
|
<!--
|
||
|
|
a.summary-letter {text-decoration: none}
|
||
|
|
blockquote.smallquotation {font-size: smaller}
|
||
|
|
div.display {margin-left: 3.2em}
|
||
|
|
div.example {margin-left: 3.2em}
|
||
|
|
div.indentedblock {margin-left: 3.2em}
|
||
|
|
div.lisp {margin-left: 3.2em}
|
||
|
|
div.smalldisplay {margin-left: 3.2em}
|
||
|
|
div.smallexample {margin-left: 3.2em}
|
||
|
|
div.smallindentedblock {margin-left: 3.2em; font-size: smaller}
|
||
|
|
div.smalllisp {margin-left: 3.2em}
|
||
|
|
kbd {font-style:oblique}
|
||
|
|
pre.display {font-family: inherit}
|
||
|
|
pre.format {font-family: inherit}
|
||
|
|
pre.menu-comment {font-family: serif}
|
||
|
|
pre.menu-preformatted {font-family: serif}
|
||
|
|
pre.smalldisplay {font-family: inherit; font-size: smaller}
|
||
|
|
pre.smallexample {font-size: smaller}
|
||
|
|
pre.smallformat {font-family: inherit; font-size: smaller}
|
||
|
|
pre.smalllisp {font-size: smaller}
|
||
|
|
span.nocodebreak {white-space:nowrap}
|
||
|
|
span.nolinebreak {white-space:nowrap}
|
||
|
|
span.roman {font-family:serif; font-weight:normal}
|
||
|
|
span.sansserif {font-family:sans-serif; font-weight:normal}
|
||
|
|
ul.no-bullet {list-style: none}
|
||
|
|
-->
|
||
|
|
</style>
|
||
|
|
|
||
|
|
|
||
|
|
</head>
|
||
|
|
|
||
|
|
<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
|
||
|
|
<a name="Overall-Options"></a>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Next: <a href="Invoking-G_002b_002b.html#Invoking-G_002b_002b" accesskey="n" rel="next">Invoking G++</a>, Previous: <a href="Option-Summary.html#Option-Summary" accesskey="p" rel="prev">Option Summary</a>, Up: <a href="Invoking-GCC.html#Invoking-GCC" accesskey="u" rel="up">Invoking GCC</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>
|
||
|
|
<hr>
|
||
|
|
<a name="Options-Controlling-the-Kind-of-Output"></a>
|
||
|
|
<h3 class="section">3.2 Options Controlling the Kind of Output</h3>
|
||
|
|
|
||
|
|
<p>Compilation can involve up to four stages: preprocessing, compilation
|
||
|
|
proper, assembly and linking, always in that order. GCC is capable of
|
||
|
|
preprocessing and compiling several files either into several
|
||
|
|
assembler input files, or into one assembler input file; then each
|
||
|
|
assembler input file produces an object file, and linking combines all
|
||
|
|
the object files (those newly compiled, and those specified as input)
|
||
|
|
into an executable file.
|
||
|
|
</p>
|
||
|
|
<a name="index-file-name-suffix"></a>
|
||
|
|
<p>For any given input file, the file name suffix determines what kind of
|
||
|
|
compilation is done:
|
||
|
|
</p>
|
||
|
|
<dl compact="compact">
|
||
|
|
<dt><code><var>file</var>.c</code></dt>
|
||
|
|
<dd><p>C source code that must be preprocessed.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.i</code></dt>
|
||
|
|
<dd><p>C source code that should not be preprocessed.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.ii</code></dt>
|
||
|
|
<dd><p>C++ source code that should not be preprocessed.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.m</code></dt>
|
||
|
|
<dd><p>Objective-C source code. Note that you must link with the <samp>libobjc</samp>
|
||
|
|
library to make an Objective-C program work.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.mi</code></dt>
|
||
|
|
<dd><p>Objective-C source code that should not be preprocessed.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.mm</code></dt>
|
||
|
|
<dt><code><var>file</var>.M</code></dt>
|
||
|
|
<dd><p>Objective-C++ source code. Note that you must link with the <samp>libobjc</samp>
|
||
|
|
library to make an Objective-C++ program work. Note that ‘<samp>.M</samp>’ refers
|
||
|
|
to a literal capital M.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.mii</code></dt>
|
||
|
|
<dd><p>Objective-C++ source code that should not be preprocessed.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.h</code></dt>
|
||
|
|
<dd><p>C, C++, Objective-C or Objective-C++ header file to be turned into a
|
||
|
|
precompiled header (default), or C, C++ header file to be turned into an
|
||
|
|
Ada spec (via the <samp>-fdump-ada-spec</samp> switch).
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.cc</code></dt>
|
||
|
|
<dt><code><var>file</var>.cp</code></dt>
|
||
|
|
<dt><code><var>file</var>.cxx</code></dt>
|
||
|
|
<dt><code><var>file</var>.cpp</code></dt>
|
||
|
|
<dt><code><var>file</var>.CPP</code></dt>
|
||
|
|
<dt><code><var>file</var>.c++</code></dt>
|
||
|
|
<dt><code><var>file</var>.C</code></dt>
|
||
|
|
<dd><p>C++ source code that must be preprocessed. Note that in ‘<samp>.cxx</samp>’,
|
||
|
|
the last two letters must both be literally ‘<samp>x</samp>’. Likewise,
|
||
|
|
‘<samp>.C</samp>’ refers to a literal capital C.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.mm</code></dt>
|
||
|
|
<dt><code><var>file</var>.M</code></dt>
|
||
|
|
<dd><p>Objective-C++ source code that must be preprocessed.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.mii</code></dt>
|
||
|
|
<dd><p>Objective-C++ source code that should not be preprocessed.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.hh</code></dt>
|
||
|
|
<dt><code><var>file</var>.H</code></dt>
|
||
|
|
<dt><code><var>file</var>.hp</code></dt>
|
||
|
|
<dt><code><var>file</var>.hxx</code></dt>
|
||
|
|
<dt><code><var>file</var>.hpp</code></dt>
|
||
|
|
<dt><code><var>file</var>.HPP</code></dt>
|
||
|
|
<dt><code><var>file</var>.h++</code></dt>
|
||
|
|
<dt><code><var>file</var>.tcc</code></dt>
|
||
|
|
<dd><p>C++ header file to be turned into a precompiled header or Ada spec.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.f</code></dt>
|
||
|
|
<dt><code><var>file</var>.for</code></dt>
|
||
|
|
<dt><code><var>file</var>.ftn</code></dt>
|
||
|
|
<dd><p>Fixed form Fortran source code that should not be preprocessed.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.F</code></dt>
|
||
|
|
<dt><code><var>file</var>.FOR</code></dt>
|
||
|
|
<dt><code><var>file</var>.fpp</code></dt>
|
||
|
|
<dt><code><var>file</var>.FPP</code></dt>
|
||
|
|
<dt><code><var>file</var>.FTN</code></dt>
|
||
|
|
<dd><p>Fixed form Fortran source code that must be preprocessed (with the traditional
|
||
|
|
preprocessor).
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.f90</code></dt>
|
||
|
|
<dt><code><var>file</var>.f95</code></dt>
|
||
|
|
<dt><code><var>file</var>.f03</code></dt>
|
||
|
|
<dt><code><var>file</var>.f08</code></dt>
|
||
|
|
<dd><p>Free form Fortran source code that should not be preprocessed.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.F90</code></dt>
|
||
|
|
<dt><code><var>file</var>.F95</code></dt>
|
||
|
|
<dt><code><var>file</var>.F03</code></dt>
|
||
|
|
<dt><code><var>file</var>.F08</code></dt>
|
||
|
|
<dd><p>Free form Fortran source code that must be preprocessed (with the
|
||
|
|
traditional preprocessor).
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.go</code></dt>
|
||
|
|
<dd><p>Go source code.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.ads</code></dt>
|
||
|
|
<dd><p>Ada source code file that contains a library unit declaration (a
|
||
|
|
declaration of a package, subprogram, or generic, or a generic
|
||
|
|
instantiation), or a library unit renaming declaration (a package,
|
||
|
|
generic, or subprogram renaming declaration). Such files are also
|
||
|
|
called <em>specs</em>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.adb</code></dt>
|
||
|
|
<dd><p>Ada source code file containing a library unit body (a subprogram or
|
||
|
|
package body). Such files are also called <em>bodies</em>.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.s</code></dt>
|
||
|
|
<dd><p>Assembler code.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>file</var>.S</code></dt>
|
||
|
|
<dt><code><var>file</var>.sx</code></dt>
|
||
|
|
<dd><p>Assembler code that must be preprocessed.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code><var>other</var></code></dt>
|
||
|
|
<dd><p>An object file to be fed straight into linking.
|
||
|
|
Any file name with no recognized suffix is treated this way.
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<a name="index-x"></a>
|
||
|
|
<p>You can specify the input language explicitly with the <samp>-x</samp> option:
|
||
|
|
</p>
|
||
|
|
<dl compact="compact">
|
||
|
|
<dt><code>-x <var>language</var></code></dt>
|
||
|
|
<dd><p>Specify explicitly the <var>language</var> for the following input files
|
||
|
|
(rather than letting the compiler choose a default based on the file
|
||
|
|
name suffix). This option applies to all following input files until
|
||
|
|
the next <samp>-x</samp> option. Possible values for <var>language</var> are:
|
||
|
|
</p><div class="smallexample">
|
||
|
|
<pre class="smallexample">c c-header cpp-output
|
||
|
|
c++ c++-header c++-cpp-output
|
||
|
|
objective-c objective-c-header objective-c-cpp-output
|
||
|
|
objective-c++ objective-c++-header objective-c++-cpp-output
|
||
|
|
assembler assembler-with-cpp
|
||
|
|
ada
|
||
|
|
f77 f77-cpp-input f95 f95-cpp-input
|
||
|
|
go
|
||
|
|
java
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
</dd>
|
||
|
|
<dt><code>-x none</code></dt>
|
||
|
|
<dd><p>Turn off any specification of a language, so that subsequent files are
|
||
|
|
handled according to their file name suffixes (as they are if <samp>-x</samp>
|
||
|
|
has not been used at all).
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<p>If you only want some of the stages of compilation, you can use
|
||
|
|
<samp>-x</samp> (or filename suffixes) to tell <code>gcc</code> where to start, and
|
||
|
|
one of the options <samp>-c</samp>, <samp>-S</samp>, or <samp>-E</samp> to say where
|
||
|
|
<code>gcc</code> is to stop. Note that some combinations (for example,
|
||
|
|
‘<samp>-x cpp-output -E</samp>’) instruct <code>gcc</code> to do nothing at all.
|
||
|
|
</p>
|
||
|
|
<dl compact="compact">
|
||
|
|
<dt><code>-c</code></dt>
|
||
|
|
<dd><a name="index-c"></a>
|
||
|
|
<p>Compile or assemble the source files, but do not link. The linking
|
||
|
|
stage simply is not done. The ultimate output is in the form of an
|
||
|
|
object file for each source file.
|
||
|
|
</p>
|
||
|
|
<p>By default, the object file name for a source file is made by replacing
|
||
|
|
the suffix ‘<samp>.c</samp>’, ‘<samp>.i</samp>’, ‘<samp>.s</samp>’, etc., with ‘<samp>.o</samp>’.
|
||
|
|
</p>
|
||
|
|
<p>Unrecognized input files, not requiring compilation or assembly, are
|
||
|
|
ignored.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-S</code></dt>
|
||
|
|
<dd><a name="index-S"></a>
|
||
|
|
<p>Stop after the stage of compilation proper; do not assemble. The output
|
||
|
|
is in the form of an assembler code file for each non-assembler input
|
||
|
|
file specified.
|
||
|
|
</p>
|
||
|
|
<p>By default, the assembler file name for a source file is made by
|
||
|
|
replacing the suffix ‘<samp>.c</samp>’, ‘<samp>.i</samp>’, etc., with ‘<samp>.s</samp>’.
|
||
|
|
</p>
|
||
|
|
<p>Input files that don’t require compilation are ignored.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-E</code></dt>
|
||
|
|
<dd><a name="index-E"></a>
|
||
|
|
<p>Stop after the preprocessing stage; do not run the compiler proper. The
|
||
|
|
output is in the form of preprocessed source code, which is sent to the
|
||
|
|
standard output.
|
||
|
|
</p>
|
||
|
|
<p>Input files that don’t require preprocessing are ignored.
|
||
|
|
</p>
|
||
|
|
<a name="index-output-file-option"></a>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-o <var>file</var></code></dt>
|
||
|
|
<dd><a name="index-o"></a>
|
||
|
|
<p>Place output in file <var>file</var>. This applies to whatever
|
||
|
|
sort of output is being produced, whether it be an executable file,
|
||
|
|
an object file, an assembler file or preprocessed C code.
|
||
|
|
</p>
|
||
|
|
<p>If <samp>-o</samp> is not specified, the default is to put an executable
|
||
|
|
file in <samp>a.out</samp>, the object file for
|
||
|
|
<samp><var>source</var>.<var>suffix</var></samp> in <samp><var>source</var>.o</samp>, its
|
||
|
|
assembler file in <samp><var>source</var>.s</samp>, a precompiled header file in
|
||
|
|
<samp><var>source</var>.<var>suffix</var>.gch</samp>, and all preprocessed C source on
|
||
|
|
standard output.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-v</code></dt>
|
||
|
|
<dd><a name="index-v"></a>
|
||
|
|
<p>Print (on standard error output) the commands executed to run the stages
|
||
|
|
of compilation. Also print the version number of the compiler driver
|
||
|
|
program and of the preprocessor and the compiler proper.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-###</code></dt>
|
||
|
|
<dd><a name="index-_0023_0023_0023"></a>
|
||
|
|
<p>Like <samp>-v</samp> except the commands are not executed and arguments
|
||
|
|
are quoted unless they contain only alphanumeric characters or <code>./-_</code>.
|
||
|
|
This is useful for shell scripts to capture the driver-generated command lines.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>--help</code></dt>
|
||
|
|
<dd><a name="index-help"></a>
|
||
|
|
<p>Print (on the standard output) a description of the command-line options
|
||
|
|
understood by <code>gcc</code>. If the <samp>-v</samp> option is also specified
|
||
|
|
then <samp>--help</samp> is also passed on to the various processes
|
||
|
|
invoked by <code>gcc</code>, so that they can display the command-line options
|
||
|
|
they accept. If the <samp>-Wextra</samp> option has also been specified
|
||
|
|
(prior to the <samp>--help</samp> option), then command-line options that
|
||
|
|
have no documentation associated with them are also displayed.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>--target-help</code></dt>
|
||
|
|
<dd><a name="index-target_002dhelp"></a>
|
||
|
|
<p>Print (on the standard output) a description of target-specific command-line
|
||
|
|
options for each tool. For some targets extra target-specific
|
||
|
|
information may also be printed.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>--help={<var>class</var><span class="roman">|[</span>^<span class="roman">]</span><var>qualifier</var>}<span class="roman">[</span>,…<span class="roman">]</span></code></dt>
|
||
|
|
<dd><p>Print (on the standard output) a description of the command-line
|
||
|
|
options understood by the compiler that fit into all specified classes
|
||
|
|
and qualifiers. These are the supported classes:
|
||
|
|
</p>
|
||
|
|
<dl compact="compact">
|
||
|
|
<dt>‘<samp>optimizers</samp>’</dt>
|
||
|
|
<dd><p>Display all of the optimization options supported by the
|
||
|
|
compiler.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt>‘<samp>warnings</samp>’</dt>
|
||
|
|
<dd><p>Display all of the options controlling warning messages
|
||
|
|
produced by the compiler.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt>‘<samp>target</samp>’</dt>
|
||
|
|
<dd><p>Display target-specific options. Unlike the
|
||
|
|
<samp>--target-help</samp> option however, target-specific options of the
|
||
|
|
linker and assembler are not displayed. This is because those
|
||
|
|
tools do not currently support the extended <samp>--help=</samp> syntax.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt>‘<samp>params</samp>’</dt>
|
||
|
|
<dd><p>Display the values recognized by the <samp>--param</samp>
|
||
|
|
option.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><var>language</var></dt>
|
||
|
|
<dd><p>Display the options supported for <var>language</var>, where
|
||
|
|
<var>language</var> is the name of one of the languages supported in this
|
||
|
|
version of GCC.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt>‘<samp>common</samp>’</dt>
|
||
|
|
<dd><p>Display the options that are common to all languages.
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<p>These are the supported qualifiers:
|
||
|
|
</p>
|
||
|
|
<dl compact="compact">
|
||
|
|
<dt>‘<samp>undocumented</samp>’</dt>
|
||
|
|
<dd><p>Display only those options that are undocumented.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt>‘<samp>joined</samp>’</dt>
|
||
|
|
<dd><p>Display options taking an argument that appears after an equal
|
||
|
|
sign in the same continuous piece of text, such as:
|
||
|
|
‘<samp>--help=target</samp>’.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt>‘<samp>separate</samp>’</dt>
|
||
|
|
<dd><p>Display options taking an argument that appears as a separate word
|
||
|
|
following the original option, such as: ‘<samp>-o output-file</samp>’.
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<p>Thus for example to display all the undocumented target-specific
|
||
|
|
switches supported by the compiler, use:
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample">--help=target,undocumented
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>The sense of a qualifier can be inverted by prefixing it with the
|
||
|
|
‘<samp>^</samp>’ character, so for example to display all binary warning
|
||
|
|
options (i.e., ones that are either on or off and that do not take an
|
||
|
|
argument) that have a description, use:
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample">--help=warnings,^joined,^undocumented
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>The argument to <samp>--help=</samp> should not consist solely of inverted
|
||
|
|
qualifiers.
|
||
|
|
</p>
|
||
|
|
<p>Combining several classes is possible, although this usually
|
||
|
|
restricts the output so much that there is nothing to display. One
|
||
|
|
case where it does work, however, is when one of the classes is
|
||
|
|
<var>target</var>. For example, to display all the target-specific
|
||
|
|
optimization options, use:
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample">--help=target,optimizers
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>The <samp>--help=</samp> option can be repeated on the command line. Each
|
||
|
|
successive use displays its requested class of options, skipping
|
||
|
|
those that have already been displayed.
|
||
|
|
</p>
|
||
|
|
<p>If the <samp>-Q</samp> option appears on the command line before the
|
||
|
|
<samp>--help=</samp> option, then the descriptive text displayed by
|
||
|
|
<samp>--help=</samp> is changed. Instead of describing the displayed
|
||
|
|
options, an indication is given as to whether the option is enabled,
|
||
|
|
disabled or set to a specific value (assuming that the compiler
|
||
|
|
knows this at the point where the <samp>--help=</samp> option is used).
|
||
|
|
</p>
|
||
|
|
<p>Here is a truncated example from the ARM port of <code>gcc</code>:
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample"> % gcc -Q -mabi=2 --help=target -c
|
||
|
|
The following options are target specific:
|
||
|
|
-mabi= 2
|
||
|
|
-mabort-on-noreturn [disabled]
|
||
|
|
-mapcs [disabled]
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>The output is sensitive to the effects of previous command-line
|
||
|
|
options, so for example it is possible to find out which optimizations
|
||
|
|
are enabled at <samp>-O2</samp> by using:
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample">-Q -O2 --help=optimizers
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>Alternatively you can discover which binary optimizations are enabled
|
||
|
|
by <samp>-O3</samp> by using:
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample">gcc -c -Q -O3 --help=optimizers > /tmp/O3-opts
|
||
|
|
gcc -c -Q -O2 --help=optimizers > /tmp/O2-opts
|
||
|
|
diff /tmp/O2-opts /tmp/O3-opts | grep enabled
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
</dd>
|
||
|
|
<dt><code>--version</code></dt>
|
||
|
|
<dd><a name="index-version"></a>
|
||
|
|
<p>Display the version number and copyrights of the invoked GCC.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-pass-exit-codes</code></dt>
|
||
|
|
<dd><a name="index-pass_002dexit_002dcodes"></a>
|
||
|
|
<p>Normally the <code>gcc</code> program exits with the code of 1 if any
|
||
|
|
phase of the compiler returns a non-success return code. If you specify
|
||
|
|
<samp>-pass-exit-codes</samp>, the <code>gcc</code> program instead returns with
|
||
|
|
the numerically highest error produced by any phase returning an error
|
||
|
|
indication. The C, C++, and Fortran front ends return 4 if an internal
|
||
|
|
compiler error is encountered.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-pipe</code></dt>
|
||
|
|
<dd><a name="index-pipe"></a>
|
||
|
|
<p>Use pipes rather than temporary files for communication between the
|
||
|
|
various stages of compilation. This fails to work on some systems where
|
||
|
|
the assembler is unable to read from a pipe; but the GNU assembler has
|
||
|
|
no trouble.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-specs=<var>file</var></code></dt>
|
||
|
|
<dd><a name="index-specs"></a>
|
||
|
|
<p>Process <var>file</var> after the compiler reads in the standard <samp>specs</samp>
|
||
|
|
file, in order to override the defaults which the <code>gcc</code> driver
|
||
|
|
program uses when determining what switches to pass to <code>cc1</code>,
|
||
|
|
<code>cc1plus</code>, <code>as</code>, <code>ld</code>, etc. More than one
|
||
|
|
<samp>-specs=<var>file</var></samp> can be specified on the command line, and they
|
||
|
|
are processed in order, from left to right. See <a href="Spec-Files.html#Spec-Files">Spec Files</a>, for
|
||
|
|
information about the format of the <var>file</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-wrapper</code></dt>
|
||
|
|
<dd><a name="index-wrapper"></a>
|
||
|
|
<p>Invoke all subcommands under a wrapper program. The name of the
|
||
|
|
wrapper program and its parameters are passed as a comma separated
|
||
|
|
list.
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample">gcc -c t.c -wrapper gdb,--args
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>This invokes all subprograms of <code>gcc</code> under
|
||
|
|
‘<samp>gdb --args</samp>’, thus the invocation of <code>cc1</code> is
|
||
|
|
‘<samp>gdb --args cc1 …</samp>’.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-fplugin=<var>name</var>.so</code></dt>
|
||
|
|
<dd><a name="index-fplugin"></a>
|
||
|
|
<p>Load the plugin code in file <var>name</var>.so, assumed to be a
|
||
|
|
shared object to be dlopen’d by the compiler. The base name of
|
||
|
|
the shared object file is used to identify the plugin for the
|
||
|
|
purposes of argument parsing (See
|
||
|
|
<samp>-fplugin-arg-<var>name</var>-<var>key</var>=<var>value</var></samp> below).
|
||
|
|
Each plugin should define the callback functions specified in the
|
||
|
|
Plugins API.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-fplugin-arg-<var>name</var>-<var>key</var>=<var>value</var></code></dt>
|
||
|
|
<dd><a name="index-fplugin_002darg"></a>
|
||
|
|
<p>Define an argument called <var>key</var> with a value of <var>value</var>
|
||
|
|
for the plugin called <var>name</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-fdump-ada-spec<span class="roman">[</span>-slim<span class="roman">]</span></code></dt>
|
||
|
|
<dd><a name="index-fdump_002dada_002dspec"></a>
|
||
|
|
<p>For C and C++ source and include files, generate corresponding Ada specs.
|
||
|
|
See <a href="../gnat_ugn/Generating-Ada-Bindings-for-C-and-C_002b_002b-headers.html#Generating-Ada-Bindings-for-C-and-C_002b_002b-headers">Generating Ada Bindings for C and C++ headers</a> in <cite>GNAT User’s Guide</cite>, which provides detailed documentation on this feature.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-fada-spec-parent=<var>unit</var></code></dt>
|
||
|
|
<dd><a name="index-fada_002dspec_002dparent"></a>
|
||
|
|
<p>In conjunction with <samp>-fdump-ada-spec<span class="roman">[</span>-slim<span class="roman">]</span></samp> above, generate
|
||
|
|
Ada specs as child units of parent <var>unit</var>.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>-fdump-go-spec=<var>file</var></code></dt>
|
||
|
|
<dd><a name="index-fdump_002dgo_002dspec"></a>
|
||
|
|
<p>For input files in any language, generate corresponding Go
|
||
|
|
declarations in <var>file</var>. This generates Go <code>const</code>,
|
||
|
|
<code>type</code>, <code>var</code>, and <code>func</code> declarations which may be a
|
||
|
|
useful way to start writing a Go interface to code written in some
|
||
|
|
other language.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
</dd>
|
||
|
|
<dt><code>@<var>file</var></code></dt>
|
||
|
|
<dd><p>Read command-line options from <var>file</var>. The options read are
|
||
|
|
inserted in place of the original @<var>file</var> option. If <var>file</var>
|
||
|
|
does not exist, or cannot be read, then the option will be treated
|
||
|
|
literally, and not removed.
|
||
|
|
</p>
|
||
|
|
<p>Options in <var>file</var> are separated by whitespace. A whitespace
|
||
|
|
character may be included in an option by surrounding the entire
|
||
|
|
option in either single or double quotes. Any character (including a
|
||
|
|
backslash) may be included by prefixing the character to be included
|
||
|
|
with a backslash. The <var>file</var> may itself contain additional
|
||
|
|
@<var>file</var> options; any such options will be processed recursively.
|
||
|
|
</p></dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<hr>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Next: <a href="Invoking-G_002b_002b.html#Invoking-G_002b_002b" accesskey="n" rel="next">Invoking G++</a>, Previous: <a href="Option-Summary.html#Option-Summary" accesskey="p" rel="prev">Option Summary</a>, Up: <a href="Invoking-GCC.html#Invoking-GCC" accesskey="u" rel="up">Invoking GCC</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>
|