126 lines
4.8 KiB
HTML
126 lines
4.8 KiB
HTML
|
<html lang="en">
|
||
|
|
<head>
|
||
|
|
<title>File Caching - Untitled</title>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html">
|
||
|
|
<meta name="description" content="Untitled">
|
||
|
|
<meta name="generator" content="makeinfo 4.7">
|
||
|
|
<link title="Top" rel="start" href="index.html#Top">
|
||
|
|
<link rel="up" href="BFD-front-end.html#BFD-front-end" title="BFD front end">
|
||
|
|
<link rel="prev" href="Internal.html#Internal" title="Internal">
|
||
|
|
<link rel="next" href="Linker-Functions.html#Linker-Functions" title="Linker Functions">
|
||
|
|
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
|
||
|
|
<!--
|
||
|
|
This file documents the BFD library.
|
||
|
|
|
||
|
|
Copyright (C) 1991, 2000, 2001, 2003, 2006, 2007 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 1.1 or
|
||
|
|
any later version published by the Free Software Foundation; with the
|
||
|
|
Invariant Sections being ``GNU General Public License'' and ``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; }
|
||
|
|
--></style>
|
||
|
|
</head>
|
||
|
|
<body>
|
||
|
|
<div class="node">
|
||
|
|
<p>
|
||
|
|
<a name="File-Caching"></a>Next: <a rel="next" accesskey="n" href="Linker-Functions.html#Linker-Functions">Linker Functions</a>,
|
||
|
|
Previous: <a rel="previous" accesskey="p" href="Internal.html#Internal">Internal</a>,
|
||
|
|
Up: <a rel="up" accesskey="u" href="BFD-front-end.html#BFD-front-end">BFD front end</a>
|
||
|
|
<hr><br>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
<h3 class="section">2.16 File caching</h3>
|
||
|
|
|
||
|
|
<p>The file caching mechanism is embedded within BFD and allows
|
||
|
|
the application to open as many BFDs as it wants without
|
||
|
|
regard to the underlying operating system's file descriptor
|
||
|
|
limit (often as low as 20 open files). The module in
|
||
|
|
<code>cache.c</code> maintains a least recently used list of
|
||
|
|
<code>BFD_CACHE_MAX_OPEN</code> files, and exports the name
|
||
|
|
<code>bfd_cache_lookup</code>, which runs around and makes sure that
|
||
|
|
the required BFD is open. If not, then it chooses a file to
|
||
|
|
close, closes it and opens the one wanted, returning its file
|
||
|
|
handle.
|
||
|
|
|
||
|
|
<h4 class="subsection">2.16.1 Caching functions</h4>
|
||
|
|
|
||
|
|
<p><a name="index-bfd_005fcache_005finit-1364"></a>
|
||
|
|
|
||
|
|
<h5 class="subsubsection">2.16.1.1 <code>bfd_cache_init</code></h5>
|
||
|
|
|
||
|
|
<p><strong>Synopsis</strong>
|
||
|
|
<pre class="example"> bfd_boolean bfd_cache_init (bfd *abfd);
|
||
|
|
</pre>
|
||
|
|
<p><strong>Description</strong><br>
|
||
|
|
Add a newly opened BFD to the cache.
|
||
|
|
|
||
|
|
<p><a name="index-bfd_005fcache_005fclose-1365"></a>
|
||
|
|
|
||
|
|
<h5 class="subsubsection">2.16.1.2 <code>bfd_cache_close</code></h5>
|
||
|
|
|
||
|
|
<p><strong>Synopsis</strong>
|
||
|
|
<pre class="example"> bfd_boolean bfd_cache_close (bfd *abfd);
|
||
|
|
</pre>
|
||
|
|
<p><strong>Description</strong><br>
|
||
|
|
Remove the BFD <var>abfd</var> from the cache. If the attached file is open,
|
||
|
|
then close it too.
|
||
|
|
|
||
|
|
<p><strong>Returns</strong><br>
|
||
|
|
<code>FALSE</code> is returned if closing the file fails, <code>TRUE</code> is
|
||
|
|
returned if all is well.
|
||
|
|
|
||
|
|
<p><a name="index-bfd_005fcache_005fclose_005fall-1366"></a>
|
||
|
|
|
||
|
|
<h5 class="subsubsection">2.16.1.3 <code>bfd_cache_close_all</code></h5>
|
||
|
|
|
||
|
|
<p><strong>Synopsis</strong>
|
||
|
|
<pre class="example"> bfd_boolean bfd_cache_close_all (void);
|
||
|
|
</pre>
|
||
|
|
<p><strong>Description</strong><br>
|
||
|
|
Remove all BFDs from the cache. If the attached file is open,
|
||
|
|
then close it too.
|
||
|
|
|
||
|
|
<p><strong>Returns</strong><br>
|
||
|
|
<code>FALSE</code> is returned if closing one of the file fails, <code>TRUE</code> is
|
||
|
|
returned if all is well.
|
||
|
|
|
||
|
|
<p><a name="index-bfd_005fopen_005ffile-1367"></a>
|
||
|
|
|
||
|
|
<h5 class="subsubsection">2.16.1.4 <code>bfd_open_file</code></h5>
|
||
|
|
|
||
|
|
<p><strong>Synopsis</strong>
|
||
|
|
<pre class="example"> FILE* bfd_open_file (bfd *abfd);
|
||
|
|
</pre>
|
||
|
|
<p><strong>Description</strong><br>
|
||
|
|
Call the OS to open a file for <var>abfd</var>. Return the <code>FILE *</code>
|
||
|
|
(possibly <code>NULL</code>) that results from this operation. Set up the
|
||
|
|
BFD so that future accesses know the file is open. If the <code>FILE *</code>
|
||
|
|
returned is <code>NULL</code>, then it won't have been put in the
|
||
|
|
cache, so it won't have to be removed from it.
|
||
|
|
|
||
|
|
</body></html>
|
||
|
|
|