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| author | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
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| committer | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
| commit | abdaadbcae30fe0c9a66c7516798279fdfd97750 (patch) | |
| tree | 00a54a6e25601e43876d03c1a4a12a749d4a914c /share/doc/cpp/Environment-Variables.html | |
https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads
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diff --git a/share/doc/cpp/Environment-Variables.html b/share/doc/cpp/Environment-Variables.html new file mode 100644 index 0000000..5848c40 --- /dev/null +++ b/share/doc/cpp/Environment-Variables.html @@ -0,0 +1,195 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- Copyright (C) 1987-2023 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. A copy of +the license is included in the +section entitled "GNU Free Documentation License". + +This manual contains no Invariant Sections. The Front-Cover Texts are +(a) (see below), and the Back-Cover Texts are (b) (see below). + +(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 5.1, http://www.gnu.org/software/texinfo/ --> +<head> +<title>The C Preprocessor: Environment Variables</title> + +<meta name="description" content="The C Preprocessor: Environment Variables"> +<meta name="keywords" content="The C Preprocessor: Environment Variables"> +<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="Index-of-Directives.html#Index-of-Directives" rel="index" title="Index of Directives"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="index.html#Top" rel="up" title="Top"> +<link href="GNU-Free-Documentation-License.html#GNU-Free-Documentation-License" rel="next" title="GNU Free Documentation License"> +<link href="Invocation.html#Invocation" rel="previous" title="Invocation"> +<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="Environment-Variables"></a> +<div class="header"> +<p> +Next: <a href="GNU-Free-Documentation-License.html#GNU-Free-Documentation-License" accesskey="n" rel="next">GNU Free Documentation License</a>, Previous: <a href="Invocation.html#Invocation" accesskey="p" rel="previous">Invocation</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index-of-Directives.html#Index-of-Directives" title="Index" rel="index">Index</a>]</p> +</div> +<hr> +<a name="Environment-Variables-1"></a> +<h2 class="chapter">13 Environment Variables</h2> +<a name="index-environment-variables"></a> + +<p>This section describes the environment variables that affect how CPP +operates. You can use them to specify directories or prefixes to use +when searching for include files, or to control dependency output. +</p> +<p>Note that you can also specify places to search using options such as +<samp>-I</samp>, and control dependency output with options like +<samp>-M</samp> (see <a href="Invocation.html#Invocation">Invocation</a>). These take precedence over +environment variables, which in turn take precedence over the +configuration of GCC. +</p> + + + +<dl compact="compact"> +<dt><code>CPATH</code> +<a name="index-CPATH"></a> +</dt> +<dt><code>C_INCLUDE_PATH</code> +<a name="index-C_005fINCLUDE_005fPATH"></a> +</dt> +<dt><code>CPLUS_INCLUDE_PATH</code> +<a name="index-CPLUS_005fINCLUDE_005fPATH"></a> +</dt> +<dt><code>OBJC_INCLUDE_PATH</code> +<a name="index-OBJC_005fINCLUDE_005fPATH"></a> +</dt> +<dd><p>Each variable’s value is a list of directories separated by a special +character, much like <code>PATH</code>, in which to look for header files. +The special character, <code>PATH_SEPARATOR</code>, is target-dependent and +determined at GCC build time. For Microsoft Windows-based targets it is a +semicolon, and for almost all other targets it is a colon. +</p> +<p><code>CPATH</code> specifies a list of directories to be searched as if +specified with <samp>-I</samp>, but after any paths given with <samp>-I</samp> +options on the command line. This environment variable is used +regardless of which language is being preprocessed. +</p> +<p>The remaining environment variables apply only when preprocessing the +particular language indicated. Each specifies a list of directories +to be searched as if specified with <samp>-isystem</samp>, but after any +paths given with <samp>-isystem</samp> options on the command line. +</p> +<p>In all these variables, an empty element instructs the compiler to +search its current working directory. Empty elements can appear at the +beginning or end of a path. For instance, if the value of +<code>CPATH</code> is <code>:/special/include</code>, that has the same +effect as ‘<samp><span class="nolinebreak">-I.</span> <span class="nolinebreak">-I/special/include</span><!-- /@w --></samp>’. +</p> +<p>See also <a href="Search-Path.html#Search-Path">Search Path</a>. +</p> +<a name="index-dependencies-for-make-as-output"></a> +</dd> +<dt><code>DEPENDENCIES_OUTPUT</code> +<a name="index-DEPENDENCIES_005fOUTPUT"></a> +</dt> +<dd><p>If this variable is set, its value specifies how to output +dependencies for Make based on the non-system header files processed +by the compiler. System header files are ignored in the dependency +output. +</p> +<p>The value of <code>DEPENDENCIES_OUTPUT</code> can be just a file name, in +which case the Make rules are written to that file, guessing the target +name from the source file name. Or the value can have the form +‘<samp><var>file</var> <var>target</var></samp>’, in which case the rules are written to +file <var>file</var> using <var>target</var> as the target name. +</p> +<p>In other words, this environment variable is equivalent to combining +the options <samp>-MM</samp> and <samp>-MF</samp> +(see <a href="Invocation.html#Invocation">Invocation</a>), +with an optional <samp>-MT</samp> switch too. +</p> +<a name="index-dependencies-for-make-as-output-1"></a> +</dd> +<dt><code>SUNPRO_DEPENDENCIES</code> +<a name="index-SUNPRO_005fDEPENDENCIES"></a> +</dt> +<dd><p>This variable is the same as <code>DEPENDENCIES_OUTPUT</code> (see above), +except that system header files are not ignored, so it implies +<samp>-M</samp> rather than <samp>-MM</samp>. However, the dependence on the +main input file is omitted. +See <a href="Invocation.html#Invocation">Invocation</a>. +</p> +</dd> +<dt><code>SOURCE_DATE_EPOCH</code> +<a name="index-SOURCE_005fDATE_005fEPOCH"></a> +</dt> +<dd><p>If this variable is set, its value specifies a UNIX timestamp to be +used in replacement of the current date and time in the <code>__DATE__</code> +and <code>__TIME__</code> macros, so that the embedded timestamps become +reproducible. +</p> +<p>The value of <code>SOURCE_DATE_EPOCH</code> must be a UNIX timestamp, +defined as the number of seconds (excluding leap seconds) since +01 Jan 1970 00:00:00 represented in ASCII; identical to the output of +<code>date +%s</code> on GNU/Linux and other systems that support the +<code>%s</code> extension in the <code>date</code> command. +</p> +<p>The value should be a known timestamp such as the last modification +time of the source or package and it should be set by the build +process. +</p> +</dd> +</dl> + +<hr> +<div class="header"> +<p> +Next: <a href="GNU-Free-Documentation-License.html#GNU-Free-Documentation-License" accesskey="n" rel="next">GNU Free Documentation License</a>, Previous: <a href="Invocation.html#Invocation" accesskey="p" rel="previous">Invocation</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index-of-Directives.html#Index-of-Directives" title="Index" rel="index">Index</a>]</p> +</div> + + + +</body> +</html> |