<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
<html>
|
<!-- Copyright (C) 1988-2021 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 1.3 or
|
any later version published by the Free Software Foundation; with the
|
Invariant Sections being "Free Software" and "Free Software Needs
|
Free Documentation", with the Front-Cover Texts being "A GNU Manual,"
|
and with the Back-Cover Texts as in (a) below.
|
|
(a) The FSF's Back-Cover Text is: "You are free to copy and modify
|
this GNU Manual. Buying copies from GNU Press supports the FSF in
|
developing GNU and promoting software freedom." -->
|
<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ -->
|
<head>
|
<title>Debugging with GDB: Breakpoints In Guile</title>
|
|
<meta name="description" content="Debugging with GDB: Breakpoints In Guile">
|
<meta name="keywords" content="Debugging with GDB: Breakpoints In Guile">
|
<meta name="resource-type" content="document">
|
<meta name="distribution" content="global">
|
<meta name="Generator" content="makeinfo">
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
<link href="index.html#Top" rel="start" title="Top">
|
<link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index">
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
<link href="Guile-API.html#Guile-API" rel="up" title="Guile API">
|
<link href="Lazy-Strings-In-Guile.html#Lazy-Strings-In-Guile" rel="next" title="Lazy Strings In Guile">
|
<link href="Symbol-Tables-In-Guile.html#Symbol-Tables-In-Guile" rel="previous" title="Symbol Tables In Guile">
|
<style type="text/css">
|
<!--
|
a.summary-letter {text-decoration: none}
|
blockquote.smallquotation {font-size: smaller}
|
div.display {margin-left: 3.2em}
|
div.example {margin-left: 3.2em}
|
div.indentedblock {margin-left: 3.2em}
|
div.lisp {margin-left: 3.2em}
|
div.smalldisplay {margin-left: 3.2em}
|
div.smallexample {margin-left: 3.2em}
|
div.smallindentedblock {margin-left: 3.2em; font-size: smaller}
|
div.smalllisp {margin-left: 3.2em}
|
kbd {font-style:oblique}
|
pre.display {font-family: inherit}
|
pre.format {font-family: inherit}
|
pre.menu-comment {font-family: serif}
|
pre.menu-preformatted {font-family: serif}
|
pre.smalldisplay {font-family: inherit; font-size: smaller}
|
pre.smallexample {font-size: smaller}
|
pre.smallformat {font-family: inherit; font-size: smaller}
|
pre.smalllisp {font-size: smaller}
|
span.nocodebreak {white-space:nowrap}
|
span.nolinebreak {white-space:nowrap}
|
span.roman {font-family:serif; font-weight:normal}
|
span.sansserif {font-family:sans-serif; font-weight:normal}
|
ul.no-bullet {list-style: none}
|
-->
|
</style>
|
|
|
</head>
|
|
<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
|
<a name="Breakpoints-In-Guile"></a>
|
<div class="header">
|
<p>
|
Next: <a href="Lazy-Strings-In-Guile.html#Lazy-Strings-In-Guile" accesskey="n" rel="next">Lazy Strings In Guile</a>, Previous: <a href="Symbol-Tables-In-Guile.html#Symbol-Tables-In-Guile" accesskey="p" rel="previous">Symbol Tables In Guile</a>, Up: <a href="Guile-API.html#Guile-API" accesskey="u" rel="up">Guile API</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
|
</div>
|
<hr>
|
<a name="Manipulating-breakpoints-using-Guile"></a>
|
<h4 class="subsubsection">23.3.3.19 Manipulating breakpoints using Guile</h4>
|
|
<a name="index-breakpoints-in-guile"></a>
|
<a name="index-_003cgdb_003abreakpoint_003e"></a>
|
|
<p>Breakpoints in Guile are represented by objects of type
|
<code><gdb:breakpoint></code>. New breakpoints can be created with the
|
<code>make-breakpoint</code> Guile function, and then added to <small>GDB</small> with the
|
<code>register-breakpoint!</code> Guile function.
|
This two-step approach is taken to separate out the side-effect of adding
|
the breakpoint to <small>GDB</small> from <code>make-breakpoint</code>.
|
</p>
|
<p>Support is also provided to view and manipulate breakpoints created
|
outside of Guile.
|
</p>
|
<p>The following breakpoint-related procedures are provided by the
|
<code>(gdb)</code> module:
|
</p>
|
<dl>
|
<dt><a name="index-make_002dbreakpoint"></a>Scheme Procedure: <strong>make-breakpoint</strong> <em>location <span class="roman">[</span>#:type type<span class="roman">]</span> <span class="roman">[</span>#:wp-class wp-class<span class="roman">]</span> <span class="roman">[</span>#:internal internal<span class="roman">]</span></em></dt>
|
<dd><p>Create a new breakpoint at <var>location</var>, a string naming the
|
location of the breakpoint, or an expression that defines a watchpoint.
|
The contents can be any location recognized by the <code>break</code> command,
|
or in the case of a watchpoint, by the <code>watch</code> command.
|
</p>
|
<p>The breakpoint is initially marked as ‘<samp>invalid</samp>’.
|
The breakpoint is not usable until it has been registered with <small>GDB</small>
|
with <code>register-breakpoint!</code>, at which point it becomes ‘<samp>valid</samp>’.
|
The result is the <code><gdb:breakpoint></code> object representing the breakpoint.
|
</p>
|
<p>The optional <var>type</var> denotes the breakpoint to create.
|
This argument can be either <code>BP_BREAKPOINT</code> or <code>BP_WATCHPOINT</code>,
|
and defaults to <code>BP_BREAKPOINT</code>.
|
</p>
|
<p>The optional <var>wp-class</var> argument defines the class of watchpoint to
|
create, if <var>type</var> is <code>BP_WATCHPOINT</code>. If a watchpoint class is
|
not provided, it is assumed to be a <code>WP_WRITE</code> class.
|
</p>
|
<p>The optional <var>internal</var> argument allows the breakpoint to become
|
invisible to the user. The breakpoint will neither be reported when
|
registered, nor will it be listed in the output from <code>info breakpoints</code>
|
(but will be listed with the <code>maint info breakpoints</code> command).
|
If an internal flag is not provided, the breakpoint is visible
|
(non-internal).
|
</p>
|
<p>When a watchpoint is created, <small>GDB</small> will try to create a
|
hardware assisted watchpoint. If successful, the type of the watchpoint
|
is changed from <code>BP_WATCHPOINT</code> to <code>BP_HARDWARE_WATCHPOINT</code>
|
for <code>WP_WRITE</code>, <code>BP_READ_WATCHPOINT</code> for <code>WP_READ</code>,
|
and <code>BP_ACCESS_WATCHPOINT</code> for <code>WP_ACCESS</code>.
|
If not successful, the type of the watchpoint is left as <code>WP_WATCHPOINT</code>.
|
</p>
|
<p>The available types are represented by constants defined in the <code>gdb</code>
|
module:
|
</p>
|
<dl compact="compact">
|
<dt><code>BP_BREAKPOINT</code>
|
<a name="index-BP_005fBREAKPOINT-1"></a>
|
</dt>
|
<dd><p>Normal code breakpoint.
|
</p>
|
</dd>
|
<dt><code>BP_WATCHPOINT</code>
|
<a name="index-BP_005fWATCHPOINT-1"></a>
|
</dt>
|
<dd><p>Watchpoint breakpoint.
|
</p>
|
</dd>
|
<dt><code>BP_HARDWARE_WATCHPOINT</code>
|
<a name="index-BP_005fHARDWARE_005fWATCHPOINT-1"></a>
|
</dt>
|
<dd><p>Hardware assisted watchpoint.
|
This value cannot be specified when creating the breakpoint.
|
</p>
|
</dd>
|
<dt><code>BP_READ_WATCHPOINT</code>
|
<a name="index-BP_005fREAD_005fWATCHPOINT-1"></a>
|
</dt>
|
<dd><p>Hardware assisted read watchpoint.
|
This value cannot be specified when creating the breakpoint.
|
</p>
|
</dd>
|
<dt><code>BP_ACCESS_WATCHPOINT</code>
|
<a name="index-BP_005fACCESS_005fWATCHPOINT-1"></a>
|
</dt>
|
<dd><p>Hardware assisted access watchpoint.
|
This value cannot be specified when creating the breakpoint.
|
</p></dd>
|
</dl>
|
|
<p>The available watchpoint types represented by constants are defined in the
|
<code>(gdb)</code> module:
|
</p>
|
<dl compact="compact">
|
<dt><code>WP_READ</code>
|
<a name="index-WP_005fREAD-1"></a>
|
</dt>
|
<dd><p>Read only watchpoint.
|
</p>
|
</dd>
|
<dt><code>WP_WRITE</code>
|
<a name="index-WP_005fWRITE-1"></a>
|
</dt>
|
<dd><p>Write only watchpoint.
|
</p>
|
</dd>
|
<dt><code>WP_ACCESS</code>
|
<a name="index-WP_005fACCESS-1"></a>
|
</dt>
|
<dd><p>Read/Write watchpoint.
|
</p></dd>
|
</dl>
|
|
</dd></dl>
|
|
<dl>
|
<dt><a name="index-register_002dbreakpoint_0021"></a>Scheme Procedure: <strong>register-breakpoint!</strong> <em>breakpoint</em></dt>
|
<dd><p>Add <var>breakpoint</var>, a <code><gdb:breakpoint></code> object, to <small>GDB</small>’s
|
list of breakpoints. The breakpoint must have been created with
|
<code>make-breakpoint</code>. One cannot register breakpoints that have been
|
created outside of Guile. Once a breakpoint is registered it becomes
|
‘<samp>valid</samp>’.
|
It is an error to register an already registered breakpoint.
|
The result is unspecified.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-delete_002dbreakpoint_0021"></a>Scheme Procedure: <strong>delete-breakpoint!</strong> <em>breakpoint</em></dt>
|
<dd><p>Remove <var>breakpoint</var> from <small>GDB</small>’s list of breakpoints.
|
This also invalidates the Guile <var>breakpoint</var> object.
|
Any further attempt to access the object will throw an exception.
|
</p>
|
<p>If <var>breakpoint</var> was created from Guile with <code>make-breakpoint</code>
|
it may be re-registered with <small>GDB</small>, in which case the breakpoint
|
becomes valid again.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-breakpoints-1"></a>Scheme Procedure: <strong>breakpoints</strong></dt>
|
<dd><p>Return a list of all breakpoints.
|
Each element of the list is a <code><gdb:breakpoint></code> object.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-breakpoint_003f"></a>Scheme Procedure: <strong>breakpoint?</strong> <em>object</em></dt>
|
<dd><p>Return <code>#t</code> if <var>object</var> is a <code><gdb:breakpoint></code> object,
|
and <code>#f</code> otherwise.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-breakpoint_002dvalid_003f"></a>Scheme Procedure: <strong>breakpoint-valid?</strong> <em>breakpoint</em></dt>
|
<dd><p>Return <code>#t</code> if <var>breakpoint</var> is valid, <code>#f</code> otherwise.
|
Breakpoints created with <code>make-breakpoint</code> are marked as invalid
|
until they are registered with <small>GDB</small> with <code>register-breakpoint!</code>.
|
A <code><gdb:breakpoint></code> object can become invalid
|
if the user deletes the breakpoint. In this case, the object still
|
exists, but the underlying breakpoint does not. In the cases of
|
watchpoint scope, the watchpoint remains valid even if execution of the
|
inferior leaves the scope of that watchpoint.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-breakpoint_002dnumber"></a>Scheme Procedure: <strong>breakpoint-number</strong> <em>breakpoint</em></dt>
|
<dd><p>Return the breakpoint’s number — the identifier used by
|
the user to manipulate the breakpoint.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-breakpoint_002dtype"></a>Scheme Procedure: <strong>breakpoint-type</strong> <em>breakpoint</em></dt>
|
<dd><p>Return the breakpoint’s type — the identifier used to
|
determine the actual breakpoint type or use-case.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-breakpoint_002dvisible_003f"></a>Scheme Procedure: <strong>breakpoint-visible?</strong> <em>breakpoint</em></dt>
|
<dd><p>Return <code>#t</code> if the breakpoint is visible to the user
|
when hit, or when the ‘<samp>info breakpoints</samp>’ command is run.
|
Otherwise return <code>#f</code>.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-breakpoint_002dlocation"></a>Scheme Procedure: <strong>breakpoint-location</strong> <em>breakpoint</em></dt>
|
<dd><p>Return the location of the breakpoint, as specified by
|
the user. It is a string. If the breakpoint does not have a location
|
(that is, it is a watchpoint) return <code>#f</code>.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-breakpoint_002dexpression"></a>Scheme Procedure: <strong>breakpoint-expression</strong> <em>breakpoint</em></dt>
|
<dd><p>Return the breakpoint expression, as specified by the user. It is a string.
|
If the breakpoint does not have an expression (the breakpoint is not a
|
watchpoint) return <code>#f</code>.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-breakpoint_002denabled_003f"></a>Scheme Procedure: <strong>breakpoint-enabled?</strong> <em>breakpoint</em></dt>
|
<dd><p>Return <code>#t</code> if the breakpoint is enabled, and <code>#f</code> otherwise.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-set_002dbreakpoint_002denabled_0021"></a>Scheme Procedure: <strong>set-breakpoint-enabled!</strong> <em>breakpoint flag</em></dt>
|
<dd><p>Set the enabled state of <var>breakpoint</var> to <var>flag</var>.
|
If flag is <code>#f</code> it is disabled, otherwise it is enabled.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-breakpoint_002dsilent_003f"></a>Scheme Procedure: <strong>breakpoint-silent?</strong> <em>breakpoint</em></dt>
|
<dd><p>Return <code>#t</code> if the breakpoint is silent, and <code>#f</code> otherwise.
|
</p>
|
<p>Note that a breakpoint can also be silent if it has commands and the
|
first command is <code>silent</code>. This is not reported by the
|
<code>silent</code> attribute.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-set_002dbreakpoint_002dsilent_0021"></a>Scheme Procedure: <strong>set-breakpoint-silent!</strong> <em>breakpoint flag</em></dt>
|
<dd><p>Set the silent state of <var>breakpoint</var> to <var>flag</var>.
|
If flag is <code>#f</code> the breakpoint is made silent,
|
otherwise it is made non-silent (or noisy).
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-breakpoint_002dignore_002dcount"></a>Scheme Procedure: <strong>breakpoint-ignore-count</strong> <em>breakpoint</em></dt>
|
<dd><p>Return the ignore count for <var>breakpoint</var>.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-set_002dbreakpoint_002dignore_002dcount_0021"></a>Scheme Procedure: <strong>set-breakpoint-ignore-count!</strong> <em>breakpoint count</em></dt>
|
<dd><p>Set the ignore count for <var>breakpoint</var> to <var>count</var>.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-breakpoint_002dhit_002dcount"></a>Scheme Procedure: <strong>breakpoint-hit-count</strong> <em>breakpoint</em></dt>
|
<dd><p>Return hit count of <var>breakpoint</var>.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-set_002dbreakpoint_002dhit_002dcount_0021"></a>Scheme Procedure: <strong>set-breakpoint-hit-count!</strong> <em>breakpoint count</em></dt>
|
<dd><p>Set the hit count of <var>breakpoint</var> to <var>count</var>.
|
At present, <var>count</var> must be zero.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-breakpoint_002dthread"></a>Scheme Procedure: <strong>breakpoint-thread</strong> <em>breakpoint</em></dt>
|
<dd><p>Return the global-thread-id for thread-specific breakpoint
|
<var>breakpoint</var>. Return #f if <var>breakpoint</var> is not
|
thread-specific.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-set_002dbreakpoint_002dthread_0021"></a>Scheme Procedure: <strong>set-breakpoint-thread!</strong> <em>breakpoint global-thread-id|#f</em></dt>
|
<dd><p>Set the thread-id for <var>breakpoint</var> to <var>global-thread-id</var> If
|
set to <code>#f</code>, the breakpoint is no longer thread-specific.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-breakpoint_002dtask"></a>Scheme Procedure: <strong>breakpoint-task</strong> <em>breakpoint</em></dt>
|
<dd><p>If the breakpoint is Ada task-specific, return the Ada task id.
|
If the breakpoint is not task-specific (or the underlying
|
language is not Ada), return <code>#f</code>.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-set_002dbreakpoint_002dtask_0021"></a>Scheme Procedure: <strong>set-breakpoint-task!</strong> <em>breakpoint task</em></dt>
|
<dd><p>Set the Ada task of <var>breakpoint</var> to <var>task</var>.
|
If set to <code>#f</code>, the breakpoint is no longer task-specific.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-breakpoint_002dcondition"></a>Scheme Procedure: <strong>breakpoint-condition</strong> <em>breakpoint</em></dt>
|
<dd><p>Return the condition of <var>breakpoint</var>, as specified by the user.
|
It is a string. If there is no condition, return <code>#f</code>.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-set_002dbreakpoint_002dcondition_0021"></a>Scheme Procedure: <strong>set-breakpoint-condition!</strong> <em>breakpoint condition</em></dt>
|
<dd><p>Set the condition of <var>breakpoint</var> to <var>condition</var>,
|
which must be a string. If set to <code>#f</code> then the breakpoint
|
becomes unconditional.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-breakpoint_002dstop"></a>Scheme Procedure: <strong>breakpoint-stop</strong> <em>breakpoint</em></dt>
|
<dd><p>Return the stop predicate of <var>breakpoint</var>.
|
See <code>set-breakpoint-stop!</code> below in this section.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-set_002dbreakpoint_002dstop_0021"></a>Scheme Procedure: <strong>set-breakpoint-stop!</strong> <em>breakpoint procedure|#f</em></dt>
|
<dd><p>Set the stop predicate of <var>breakpoint</var>. The predicate
|
<var>procedure</var> takes one argument: the <gdb:breakpoint> object.
|
If this predicate is set to a procedure then it is invoked whenever
|
the inferior reaches this breakpoint. If it returns <code>#t</code>,
|
or any non-<code>#f</code> value, then the inferior is stopped,
|
otherwise the inferior will continue.
|
</p>
|
<p>If there are multiple breakpoints at the same location with a
|
<code>stop</code> predicate, each one will be called regardless of the
|
return status of the previous. This ensures that all <code>stop</code>
|
predicates have a chance to execute at that location. In this scenario
|
if one of the methods returns <code>#t</code> but the others return
|
<code>#f</code>, the inferior will still be stopped.
|
</p>
|
<p>You should not alter the execution state of the inferior (i.e., step,
|
next, etc.), alter the current frame context (i.e., change the current
|
active frame), or alter, add or delete any breakpoint. As a general
|
rule, you should not alter any data within <small>GDB</small> or the inferior
|
at this time.
|
</p>
|
<p>Example <code>stop</code> implementation:
|
</p>
|
<div class="smallexample">
|
<pre class="smallexample">(define (my-stop? bkpt)
|
(let ((int-val (parse-and-eval "foo")))
|
(value=? int-val 3)))
|
(define bkpt (make-breakpoint "main.c:42"))
|
(register-breakpoint! bkpt)
|
(set-breakpoint-stop! bkpt my-stop?)
|
</pre></div>
|
</dd></dl>
|
|
<dl>
|
<dt><a name="index-breakpoint_002dcommands"></a>Scheme Procedure: <strong>breakpoint-commands</strong> <em>breakpoint</em></dt>
|
<dd><p>Return the commands attached to <var>breakpoint</var> as a string,
|
or <code>#f</code> if there are none.
|
</p></dd></dl>
|
|
<hr>
|
<div class="header">
|
<p>
|
Next: <a href="Lazy-Strings-In-Guile.html#Lazy-Strings-In-Guile" accesskey="n" rel="next">Lazy Strings In Guile</a>, Previous: <a href="Symbol-Tables-In-Guile.html#Symbol-Tables-In-Guile" accesskey="p" rel="previous">Symbol Tables In Guile</a>, Up: <a href="Guile-API.html#Guile-API" accesskey="u" rel="up">Guile API</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
|
</div>
|
|
|
|
</body>
|
</html>
|
