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83 lines
4.4 KiB
HTML
83 lines
4.4 KiB
HTML
4 years ago
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<html lang="en">
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<head>
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<title>Environment - Untitled</title>
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<meta http-equiv="Content-Type" content="text/html">
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<meta name="description" content="Untitled">
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<meta name="generator" content="makeinfo 4.13">
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<link title="Top" rel="start" href="index.html#Top">
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<link rel="up" href="Invocation.html#Invocation" title="Invocation">
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<link rel="prev" href="Options.html#Options" title="Options">
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<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
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<!--
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This file documents the GNU linker LD
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(GNU Binutils)
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version 2.26.
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Copyright (C) 1991-2015 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
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or any later version published by the Free Software Foundation;
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with no Invariant Sections, with no Front-Cover Texts, and with no
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Back-Cover Texts. A copy of the license is included in the
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section entitled ``GNU Free Documentation License''.-->
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<meta http-equiv="Content-Style-Type" content="text/css">
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<style type="text/css"><!--
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pre.display { font-family:inherit }
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pre.format { font-family:inherit }
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pre.smalldisplay { font-family:inherit; font-size:smaller }
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pre.smallformat { font-family:inherit; font-size:smaller }
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pre.smallexample { font-size:smaller }
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pre.smalllisp { font-size:smaller }
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span.sc { font-variant:small-caps }
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span.roman { font-family:serif; font-weight:normal; }
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span.sansserif { font-family:sans-serif; font-weight:normal; }
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--></style>
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</head>
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<body>
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<div class="node">
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<a name="Environment"></a>
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<p>
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Previous: <a rel="previous" accesskey="p" href="Options.html#Options">Options</a>,
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Up: <a rel="up" accesskey="u" href="Invocation.html#Invocation">Invocation</a>
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<hr>
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</div>
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<h3 class="section">2.2 Environment Variables</h3>
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<!-- man begin ENVIRONMENT -->
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<p>You can change the behaviour of <samp><span class="command">ld</span></samp> with the environment variables
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<code>GNUTARGET</code>,
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<code>LDEMULATION</code> and <code>COLLECT_NO_DEMANGLE</code>.
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<p><a name="index-GNUTARGET-357"></a><a name="index-default-input-format-358"></a><code>GNUTARGET</code> determines the input-file object format if you don't
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use ‘<samp><span class="samp">-b</span></samp>’ (or its synonym ‘<samp><span class="samp">--format</span></samp>’). Its value should be one
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of the BFD names for an input format (see <a href="BFD.html#BFD">BFD</a>). If there is no
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<code>GNUTARGET</code> in the environment, <samp><span class="command">ld</span></samp> uses the natural format
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of the target. If <code>GNUTARGET</code> is set to <code>default</code> then BFD
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attempts to discover the input format by examining binary input files;
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this method often succeeds, but there are potential ambiguities, since
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there is no method of ensuring that the magic number used to specify
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object-file formats is unique. However, the configuration procedure for
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BFD on each system places the conventional format for that system first
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in the search-list, so ambiguities are resolved in favor of convention.
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<p><a name="index-LDEMULATION-359"></a><a name="index-default-emulation-360"></a><a name="index-emulation_002c-default-361"></a><code>LDEMULATION</code> determines the default emulation if you don't use the
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‘<samp><span class="samp">-m</span></samp>’ option. The emulation can affect various aspects of linker
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behaviour, particularly the default linker script. You can list the
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available emulations with the ‘<samp><span class="samp">--verbose</span></samp>’ or ‘<samp><span class="samp">-V</span></samp>’ options. If
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the ‘<samp><span class="samp">-m</span></samp>’ option is not used, and the <code>LDEMULATION</code> environment
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variable is not defined, the default emulation depends upon how the
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linker was configured.
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<p><a name="index-COLLECT_005fNO_005fDEMANGLE-362"></a><a name="index-demangling_002c-default-363"></a>Normally, the linker will default to demangling symbols. However, if
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<code>COLLECT_NO_DEMANGLE</code> is set in the environment, then it will
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default to not demangling symbols. This environment variable is used in
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a similar fashion by the <code>gcc</code> linker wrapper program. The default
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may be overridden by the ‘<samp><span class="samp">--demangle</span></samp>’ and ‘<samp><span class="samp">--no-demangle</span></samp>’
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options.
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<!-- man end -->
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</body></html>
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