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160 lines
6.6 KiB
HTML
160 lines
6.6 KiB
HTML
4 years ago
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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) 1991-2019 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 6.4, http://www.gnu.org/software/texinfo/ -->
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<head>
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<title>File Caching (Untitled Document)</title>
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<meta name="description" content="File Caching (Untitled Document)">
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<meta name="keywords" content="File Caching (Untitled Document)">
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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="BFD-front-end.html#BFD-front-end" rel="up" title="BFD front end">
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<link href="Linker-Functions.html#Linker-Functions" rel="next" title="Linker Functions">
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<link href="Internal.html#Internal" rel="prev" title="Internal">
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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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div.display {margin-left: 3.2em}
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div.example {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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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.smalllisp {font-size: smaller}
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span.nolinebreak {white-space: nowrap}
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span.roman {font-family: initial; 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">
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<a name="File-Caching"></a>
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<div class="header">
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<p>
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Next: <a href="Linker-Functions.html#Linker-Functions" accesskey="n" rel="next">Linker Functions</a>, Previous: <a href="Internal.html#Internal" accesskey="p" rel="prev">Internal</a>, Up: <a href="BFD-front-end.html#BFD-front-end" accesskey="u" rel="up">BFD front end</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="File-caching"></a>
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<h3 class="section">2.16 File caching</h3>
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<p>The file caching mechanism is embedded within BFD and allows
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the application to open as many BFDs as it wants without
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regard to the underlying operating system’s file descriptor
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limit (often as low as 20 open files). The module in
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<code>cache.c</code> maintains a least recently used list of
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<code>bfd_cache_max_open</code> files, and exports the name
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<code>bfd_cache_lookup</code>, which runs around and makes sure that
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the required BFD is open. If not, then it chooses a file to
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close, closes it and opens the one wanted, returning its file
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handle.
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</p>
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<a name="Caching-functions"></a>
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<h4 class="subsection">2.16.1 Caching functions</h4>
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<a name="index-bfd_005fcache_005finit"></a>
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<a name="bfd_005fcache_005finit"></a>
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<h4 class="subsubsection">2.16.1.1 <code>bfd_cache_init</code></h4>
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<p><strong>Synopsis</strong>
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</p><div class="example">
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<pre class="example">bfd_boolean bfd_cache_init (bfd *abfd);
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</pre></div>
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<p><strong>Description</strong><br>
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Add a newly opened BFD to the cache.
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</p>
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<a name="index-bfd_005fcache_005fclose"></a>
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<a name="bfd_005fcache_005fclose"></a>
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<h4 class="subsubsection">2.16.1.2 <code>bfd_cache_close</code></h4>
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<p><strong>Synopsis</strong>
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</p><div class="example">
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<pre class="example">bfd_boolean bfd_cache_close (bfd *abfd);
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</pre></div>
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<p><strong>Description</strong><br>
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Remove the BFD <var>abfd</var> from the cache. If the attached file is open,
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then close it too.
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</p>
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<p><strong>Returns</strong><br>
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<code>FALSE</code> is returned if closing the file fails, <code>TRUE</code> is
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returned if all is well.
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</p>
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<a name="index-bfd_005fcache_005fclose_005fall"></a>
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<a name="bfd_005fcache_005fclose_005fall"></a>
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<h4 class="subsubsection">2.16.1.3 <code>bfd_cache_close_all</code></h4>
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<p><strong>Synopsis</strong>
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</p><div class="example">
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<pre class="example">bfd_boolean bfd_cache_close_all (void);
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</pre></div>
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<p><strong>Description</strong><br>
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Remove all BFDs from the cache. If the attached file is open,
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then close it too.
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</p>
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<p><strong>Returns</strong><br>
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<code>FALSE</code> is returned if closing one of the file fails, <code>TRUE</code> is
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returned if all is well.
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</p>
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<a name="index-bfd_005fopen_005ffile"></a>
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<a name="bfd_005fopen_005ffile"></a>
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<h4 class="subsubsection">2.16.1.4 <code>bfd_open_file</code></h4>
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<p><strong>Synopsis</strong>
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</p><div class="example">
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<pre class="example">FILE* bfd_open_file (bfd *abfd);
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</pre></div>
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<p><strong>Description</strong><br>
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Call the OS to open a file for <var>abfd</var>. Return the <code>FILE *</code>
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(possibly <code>NULL</code>) that results from this operation. Set up the
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BFD so that future accesses know the file is open. If the <code>FILE *</code>
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returned is <code>NULL</code>, then it won’t have been put in the
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cache, so it won’t have to be removed from it.
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</p>
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<hr>
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<div class="header">
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<p>
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Next: <a href="Linker-Functions.html#Linker-Functions" accesskey="n" rel="next">Linker Functions</a>, Previous: <a href="Internal.html#Internal" accesskey="p" rel="prev">Internal</a>, Up: <a href="BFD-front-end.html#BFD-front-end" accesskey="u" rel="up">BFD front end</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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</body>
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</html>
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