132 lines
5.1 KiB
HTML
132 lines
5.1 KiB
HTML
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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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<!-- This file documents the BFD library.
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Copyright (C) 1991-2016 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 "GNU General Public License" and "Funding
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Free Software", the Front-Cover texts being (a) (see below), and with
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the Back-Cover Texts being (b) (see below). A copy of the license is
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included in the section entitled "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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software. Copies published by the Free Software Foundation raise
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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>Untitled Document: Writing Symbols</title>
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<meta name="description" content="Untitled Document: Writing Symbols">
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<meta name="keywords" content="Untitled Document: Writing Symbols">
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<meta name="resource-type" content="document">
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<meta name="distribution" content="global">
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<meta name="Generator" content="makeinfo">
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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="BFD-Index.html#BFD-Index" rel="index" title="BFD Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="Symbols.html#Symbols" rel="up" title="Symbols">
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<link href="Mini-Symbols.html#Mini-Symbols" rel="next" title="Mini Symbols">
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<link href="Reading-Symbols.html#Reading-Symbols" rel="prev" title="Reading Symbols">
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<style type="text/css">
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<!--
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a.summary-letter {text-decoration: none}
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blockquote.smallquotation {font-size: smaller}
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div.display {margin-left: 3.2em}
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div.example {margin-left: 3.2em}
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div.indentedblock {margin-left: 3.2em}
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div.lisp {margin-left: 3.2em}
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div.smalldisplay {margin-left: 3.2em}
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div.smallexample {margin-left: 3.2em}
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div.smallindentedblock {margin-left: 3.2em; font-size: smaller}
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div.smalllisp {margin-left: 3.2em}
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kbd {font-style:oblique}
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pre.display {font-family: inherit}
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pre.format {font-family: inherit}
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pre.menu-comment {font-family: serif}
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pre.menu-preformatted {font-family: serif}
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pre.smalldisplay {font-family: inherit; font-size: smaller}
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pre.smallexample {font-size: smaller}
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pre.smallformat {font-family: inherit; font-size: smaller}
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pre.smalllisp {font-size: smaller}
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span.nocodebreak {white-space:nowrap}
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span.nolinebreak {white-space:nowrap}
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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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ul.no-bullet {list-style: none}
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-->
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</style>
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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="Writing-Symbols"></a>
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<div class="header">
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<p>
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Next: <a href="Mini-Symbols.html#Mini-Symbols" accesskey="n" rel="next">Mini Symbols</a>, Previous: <a href="Reading-Symbols.html#Reading-Symbols" accesskey="p" rel="prev">Reading Symbols</a>, Up: <a href="Symbols.html#Symbols" accesskey="u" rel="up">Symbols</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="BFD-Index.html#BFD-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<a name="Writing-symbols"></a>
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<h4 class="subsection">2.7.2 Writing symbols</h4>
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<p>Writing of a symbol table is automatic when a BFD open for
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writing is closed. The application attaches a vector of
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pointers to pointers to symbols to the BFD being written, and
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fills in the symbol count. The close and cleanup code reads
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through the table provided and performs all the necessary
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operations. The BFD output code must always be provided with an
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“owned” symbol: one which has come from another BFD, or one
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which has been created using <code>bfd_make_empty_symbol</code>. Here is an
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example showing the creation of a symbol table with only one element:
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</p>
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<div class="example">
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<pre class="example"> #include "sysdep.h"
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#include "bfd.h"
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int main (void)
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{
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bfd *abfd;
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asymbol *ptrs[2];
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asymbol *new;
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abfd = bfd_openw ("foo","a.out-sunos-big");
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bfd_set_format (abfd, bfd_object);
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new = bfd_make_empty_symbol (abfd);
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new->name = "dummy_symbol";
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new->section = bfd_make_section_old_way (abfd, ".text");
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new->flags = BSF_GLOBAL;
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new->value = 0x12345;
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ptrs[0] = new;
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ptrs[1] = 0;
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bfd_set_symtab (abfd, ptrs, 1);
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bfd_close (abfd);
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return 0;
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}
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./makesym
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nm foo
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00012345 A dummy_symbol
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</pre></div>
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<p>Many formats cannot represent arbitrary symbol information; for
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instance, the <code>a.out</code> object format does not allow an
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arbitrary number of sections. A symbol pointing to a section
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which is not one of <code>.text</code>, <code>.data</code> or <code>.bss</code> cannot
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be described.
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</p>
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</body>
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</html>
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