130 lines
6.5 KiB
HTML
130 lines
6.5 KiB
HTML
|
<!DOCTYPE html>
|
||
|
|
<html>
|
||
|
|
<!-- Created by GNU Texinfo 7.1, https://www.gnu.org/software/texinfo/ -->
|
||
|
|
<head>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
||
|
|
<!-- This manual documents Guile version 3.0.10.
|
||
|
|
|
||
|
|
Copyright (C) 1996-1997, 2000-2005, 2009-2023 Free Software Foundation,
|
||
|
|
Inc.
|
||
|
|
|
||
|
|
Copyright (C) 2021 Maxime Devos
|
||
|
|
|
||
|
|
Copyright (C) 2024 Tomas Volf
|
||
|
|
|
||
|
|
|
||
|
|
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; with no
|
||
|
|
Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
|
||
|
|
copy of the license is included in the section entitled "GNU Free
|
||
|
|
Documentation License." -->
|
||
|
|
<title>Trap States (Guile Reference Manual)</title>
|
||
|
|
|
||
|
|
<meta name="description" content="Trap States (Guile Reference Manual)">
|
||
|
|
<meta name="keywords" content="Trap States (Guile Reference Manual)">
|
||
|
|
<meta name="resource-type" content="document">
|
||
|
|
<meta name="distribution" content="global">
|
||
|
|
<meta name="Generator" content=".texi2any-real">
|
||
|
|
<meta name="viewport" content="width=device-width,initial-scale=1">
|
||
|
|
|
||
|
|
<link href="index.html" rel="start" title="Top">
|
||
|
|
<link href="Concept-Index.html" rel="index" title="Concept Index">
|
||
|
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
||
|
|
<link href="Traps.html" rel="up" title="Traps">
|
||
|
|
<link href="High_002dLevel-Traps.html" rel="next" title="High-Level Traps">
|
||
|
|
<link href="Tracing-Traps.html" rel="prev" title="Tracing Traps">
|
||
|
|
<style type="text/css">
|
||
|
|
<!--
|
||
|
|
a.copiable-link {visibility: hidden; text-decoration: none; line-height: 0em}
|
||
|
|
div.example {margin-left: 3.2em}
|
||
|
|
span:hover a.copiable-link {visibility: visible}
|
||
|
|
strong.def-name {font-family: monospace; font-weight: bold; font-size: larger}
|
||
|
|
-->
|
||
|
|
</style>
|
||
|
|
<link rel="stylesheet" type="text/css" href="https://www.gnu.org/software/gnulib/manual.css">
|
||
|
|
|
||
|
|
|
||
|
|
</head>
|
||
|
|
|
||
|
|
<body lang="en">
|
||
|
|
<div class="subsubsection-level-extent" id="Trap-States">
|
||
|
|
<div class="nav-panel">
|
||
|
|
<p>
|
||
|
|
Next: <a href="High_002dLevel-Traps.html" accesskey="n" rel="next">High-Level Traps</a>, Previous: <a href="Tracing-Traps.html" accesskey="p" rel="prev">Tracing Traps</a>, Up: <a href="Traps.html" accesskey="u" rel="up">Traps</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
|
||
|
|
</div>
|
||
|
|
<hr>
|
||
|
|
<h4 class="subsubsection" id="Trap-States-1"><span>6.26.4.5 Trap States<a class="copiable-link" href="#Trap-States-1"> ¶</a></span></h4>
|
||
|
|
|
||
|
|
<p>When multiple traps are present in a system, we begin to have a
|
||
|
|
bookkeeping problem. How are they named? How does one disable, enable,
|
||
|
|
or delete them?
|
||
|
|
</p>
|
||
|
|
<p>Guile’s answer to this is to keep an implicit per-thread <em class="dfn">trap
|
||
|
|
state</em>. The trap state object is not exposed to the user; rather, API
|
||
|
|
that works on trap states fetches the current trap state from the
|
||
|
|
dynamic environment.
|
||
|
|
</p>
|
||
|
|
<p>Traps are identified by integers. A trap can be enabled, disabled, or
|
||
|
|
removed, and can have an associated user-visible name.
|
||
|
|
</p>
|
||
|
|
<p>These procedures have their own module:
|
||
|
|
</p>
|
||
|
|
<div class="example lisp">
|
||
|
|
<pre class="lisp-preformatted">(use-modules (system vm trap-state))
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<dl class="first-deffn">
|
||
|
|
<dt class="deffn" id="index-add_002dtrap_0021"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">add-trap!</strong> <var class="def-var-arguments">trap name</var><a class="copiable-link" href="#index-add_002dtrap_0021"> ¶</a></span></dt>
|
||
|
|
<dd><p>Add a trap to the current trap state, associating the given <var class="var">name</var>
|
||
|
|
with it. Returns a fresh trap identifier (an integer).
|
||
|
|
</p>
|
||
|
|
<p>Note that usually the more specific functions detailed in
|
||
|
|
<a class="ref" href="High_002dLevel-Traps.html">High-Level Traps</a> are used in preference to this one.
|
||
|
|
</p></dd></dl>
|
||
|
|
|
||
|
|
<dl class="first-deffn">
|
||
|
|
<dt class="deffn" id="index-list_002dtraps"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">list-traps</strong><a class="copiable-link" href="#index-list_002dtraps"> ¶</a></span></dt>
|
||
|
|
<dd><p>List the current set of traps, both enabled and disabled. Returns a list
|
||
|
|
of integers.
|
||
|
|
</p></dd></dl>
|
||
|
|
|
||
|
|
<dl class="first-deffn">
|
||
|
|
<dt class="deffn" id="index-trap_002dname"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">trap-name</strong> <var class="def-var-arguments">idx</var><a class="copiable-link" href="#index-trap_002dname"> ¶</a></span></dt>
|
||
|
|
<dd><p>Returns the name associated with trap <var class="var">idx</var>, or <code class="code">#f</code> if there
|
||
|
|
is no such trap.
|
||
|
|
</p></dd></dl>
|
||
|
|
|
||
|
|
<dl class="first-deffn">
|
||
|
|
<dt class="deffn" id="index-trap_002denabled_003f"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">trap-enabled?</strong> <var class="def-var-arguments">idx</var><a class="copiable-link" href="#index-trap_002denabled_003f"> ¶</a></span></dt>
|
||
|
|
<dd><p>Returns <code class="code">#t</code> if trap <var class="var">idx</var> is present and enabled, or <code class="code">#f</code>
|
||
|
|
otherwise.
|
||
|
|
</p></dd></dl>
|
||
|
|
|
||
|
|
<dl class="first-deffn">
|
||
|
|
<dt class="deffn" id="index-enable_002dtrap_0021"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">enable-trap!</strong> <var class="def-var-arguments">idx</var><a class="copiable-link" href="#index-enable_002dtrap_0021"> ¶</a></span></dt>
|
||
|
|
<dd><p>Enables trap <var class="var">idx</var>.
|
||
|
|
</p></dd></dl>
|
||
|
|
|
||
|
|
<dl class="first-deffn">
|
||
|
|
<dt class="deffn" id="index-disable_002dtrap_0021"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">disable-trap!</strong> <var class="def-var-arguments">idx</var><a class="copiable-link" href="#index-disable_002dtrap_0021"> ¶</a></span></dt>
|
||
|
|
<dd><p>Disables trap <var class="var">idx</var>.
|
||
|
|
</p></dd></dl>
|
||
|
|
|
||
|
|
<dl class="first-deffn">
|
||
|
|
<dt class="deffn" id="index-delete_002dtrap_0021"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">delete-trap!</strong> <var class="def-var-arguments">idx</var><a class="copiable-link" href="#index-delete_002dtrap_0021"> ¶</a></span></dt>
|
||
|
|
<dd><p>Removes trap <var class="var">idx</var>, disabling it first, if necessary.
|
||
|
|
</p></dd></dl>
|
||
|
|
|
||
|
|
</div>
|
||
|
|
<hr>
|
||
|
|
<div class="nav-panel">
|
||
|
|
<p>
|
||
|
|
Next: <a href="High_002dLevel-Traps.html">High-Level Traps</a>, Previous: <a href="Tracing-Traps.html">Tracing Traps</a>, Up: <a href="Traps.html">Traps</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|