<html lang="en">
<head>
<title>Front End Config - GNU Compiler Collection (GCC) Internals</title>
<meta http-equiv="Content-Type" content="text/html">
<meta name="description" content="GNU Compiler Collection (GCC) Internals">
<meta name="generator" content="makeinfo 4.13">
<link title="Top" rel="start" href="index.html#Top">
<link rel="up" href="Front-End.html#Front-End" title="Front End">
<link rel="prev" href="Front-End-Directory.html#Front-End-Directory" title="Front End Directory">
<link rel="next" href="Front-End-Makefile.html#Front-End-Makefile" title="Front End Makefile">
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
<!--
Copyright (C) 1988-2015 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.-->
<meta http-equiv="Content-Style-Type" content="text/css">
<style type="text/css"><!--
pre.display { font-family:inherit }
pre.format { font-family:inherit }
pre.smalldisplay { font-family:inherit; font-size:smaller }
pre.smallformat { font-family:inherit; font-size:smaller }
pre.smallexample { font-size:smaller }
pre.smalllisp { font-size:smaller }
span.sc { font-variant:small-caps }
span.roman { font-family:serif; font-weight:normal; }
span.sansserif { font-family:sans-serif; font-weight:normal; }
--></style>
</head>
<body>
<div class="node">
<a name="Front-End-Config"></a>
<p>
Next: <a rel="next" accesskey="n" href="Front-End-Makefile.html#Front-End-Makefile">Front End Makefile</a>,
Previous: <a rel="previous" accesskey="p" href="Front-End-Directory.html#Front-End-Directory">Front End Directory</a>,
Up: <a rel="up" accesskey="u" href="Front-End.html#Front-End">Front End</a>
<hr>
</div>
<h5 class="subsubsection">6.3.8.2 The Front End <samp><span class="file">config-lang.in</span></samp> File</h5>
<p>Each language subdirectory contains a <samp><span class="file">config-lang.in</span></samp> file.
This file is a shell script that may define some variables describing
the language:
<dl>
<dt><code>language</code><dd>This definition must be present, and gives the name of the language
for some purposes such as arguments to <samp><span class="option">--enable-languages</span></samp>.
<br><dt><code>lang_requires</code><dd>If defined, this variable lists (space-separated) language front ends
other than C that this front end requires to be enabled (with the
names given being their <code>language</code> settings). For example, the
Java front end depends on the C++ front end, so sets
‘<samp><span class="samp">lang_requires=c++</span></samp>’.
<br><dt><code>subdir_requires</code><dd>If defined, this variable lists (space-separated) front end directories
other than C that this front end requires to be present. For example,
the Objective-C++ front end uses source files from the C++ and
Objective-C front ends, so sets ‘<samp><span class="samp">subdir_requires="cp objc"</span></samp>’.
<br><dt><code>target_libs</code><dd>If defined, this variable lists (space-separated) targets in the top
level <samp><span class="file">Makefile</span></samp> to build the runtime libraries for this
language, such as <code>target-libobjc</code>.
<br><dt><code>lang_dirs</code><dd>If defined, this variable lists (space-separated) top level
directories (parallel to <samp><span class="file">gcc</span></samp>), apart from the runtime libraries,
that should not be configured if this front end is not built.
<br><dt><code>build_by_default</code><dd>If defined to ‘<samp><span class="samp">no</span></samp>’, this language front end is not built unless
enabled in a <samp><span class="option">--enable-languages</span></samp> argument. Otherwise, front
ends are built by default, subject to any special logic in
<samp><span class="file">configure.ac</span></samp> (as is present to disable the Ada front end if the
Ada compiler is not already installed).
<br><dt><code>boot_language</code><dd>If defined to ‘<samp><span class="samp">yes</span></samp>’, this front end is built in stage1 of the
bootstrap. This is only relevant to front ends written in their own
languages.
<br><dt><code>compilers</code><dd>If defined, a space-separated list of compiler executables that will
be run by the driver. The names here will each end
with ‘<samp><span class="samp">\$(exeext)</span></samp>’.
<br><dt><code>outputs</code><dd>If defined, a space-separated list of files that should be generated
by <samp><span class="file">configure</span></samp> substituting values in them. This mechanism can
be used to create a file <samp><var>language</var><span class="file">/Makefile</span></samp> from
<samp><var>language</var><span class="file">/Makefile.in</span></samp>, but this is deprecated, building
everything from the single <samp><span class="file">gcc/Makefile</span></samp> is preferred.
<br><dt><code>gtfiles</code><dd>If defined, a space-separated list of files that should be scanned by
<samp><span class="file">gengtype.c</span></samp> to generate the garbage collection tables and routines for
this language. This excludes the files that are common to all front
ends. See <a href="Type-Information.html#Type-Information">Type Information</a>.
</dl>
</body></html>