| <html lang="en"> |
| <head> |
| <title>Breakpoints In Guile - Debugging with GDB</title> |
| <meta http-equiv="Content-Type" content="text/html"> |
| <meta name="description" content="Debugging with GDB"> |
| <meta name="generator" content="makeinfo 4.13"> |
| <link title="Top" rel="start" href="index.html#Top"> |
| <link rel="up" href="Guile-API.html#Guile-API" title="Guile API"> |
| <link rel="prev" href="Symbol-Tables-In-Guile.html#Symbol-Tables-In-Guile" title="Symbol Tables In Guile"> |
| <link rel="next" href="Lazy-Strings-In-Guile.html#Lazy-Strings-In-Guile" title="Lazy Strings In Guile"> |
| <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> |
| <!-- |
| Copyright (C) 1988-2019 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.'' |
| --> |
| <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; } |
| span.sansserif { font-family:sans-serif; font-weight:normal; } |
| --></style> |
| </head> |
| <body> |
| <div class="node"> |
| <a name="Breakpoints-In-Guile"></a> |
| <p> |
| Next: <a rel="next" accesskey="n" href="Lazy-Strings-In-Guile.html#Lazy-Strings-In-Guile">Lazy Strings In Guile</a>, |
| Previous: <a rel="previous" accesskey="p" href="Symbol-Tables-In-Guile.html#Symbol-Tables-In-Guile">Symbol Tables In Guile</a>, |
| Up: <a rel="up" accesskey="u" href="Guile-API.html#Guile-API">Guile API</a> |
| <hr> |
| </div> |
| |
| <h5 class="subsubsection">23.3.3.19 Manipulating breakpoints using Guile</h5> |
| |
| <p><a name="index-breakpoints-in-guile-2766"></a><a name="index-g_t_003cgdb_003abreakpoint_003e-2767"></a> |
| 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 <span class="sc">gdb</span> 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 <span class="sc">gdb</span> from <code>make-breakpoint</code>. |
| |
| <p>Support is also provided to view and manipulate breakpoints created |
| outside of Guile. |
| |
| <p>The following breakpoint-related procedures are provided by the |
| <code>(gdb)</code> module: |
| |
| <!-- TODO: line length --> |
| <div class="defun"> |
| — Scheme Procedure: <b>make-breakpoint</b><var> location </var><span class="roman">[</span><var>#:type type</var><span class="roman">]</span> <span class="roman">[</span><var>#:wp-class wp-class</var><span class="roman">]</span> <span class="roman">[</span><var>#:internal internal</var><span class="roman">]</span><var><a name="index-make_002dbreakpoint-2768"></a></var><br> |
| <blockquote><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>The breakpoint is initially marked as ‘<samp><span class="samp">invalid</span></samp>’. |
| The breakpoint is not usable until it has been registered with <span class="sc">gdb</span> |
| with <code>register-breakpoint!</code>, at which point it becomes ‘<samp><span class="samp">valid</span></samp>’. |
| The result is the <code><gdb:breakpoint></code> object representing the breakpoint. |
| |
| <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>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>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>When a watchpoint is created, <span class="sc">gdb</span> 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>The available types are represented by constants defined in the <code>gdb</code> |
| module: |
| |
| <dl> |
| <dt><code>BP_BREAKPOINT</code><a name="index-BP_005fBREAKPOINT-2769"></a><dd>Normal code breakpoint. |
| |
| <br><dt><code>BP_WATCHPOINT</code><a name="index-BP_005fWATCHPOINT-2770"></a><dd>Watchpoint breakpoint. |
| |
| <br><dt><code>BP_HARDWARE_WATCHPOINT</code><a name="index-BP_005fHARDWARE_005fWATCHPOINT-2771"></a><dd>Hardware assisted watchpoint. |
| This value cannot be specified when creating the breakpoint. |
| |
| <br><dt><code>BP_READ_WATCHPOINT</code><a name="index-BP_005fREAD_005fWATCHPOINT-2772"></a><dd>Hardware assisted read watchpoint. |
| This value cannot be specified when creating the breakpoint. |
| |
| <br><dt><code>BP_ACCESS_WATCHPOINT</code><a name="index-BP_005fACCESS_005fWATCHPOINT-2773"></a><dd>Hardware assisted access watchpoint. |
| This value cannot be specified when creating the breakpoint. |
| </dl> |
| |
| <p>The available watchpoint types represented by constants are defined in the |
| <code>(gdb)</code> module: |
| |
| <dl> |
| <dt><code>WP_READ</code><a name="index-WP_005fREAD-2774"></a><dd>Read only watchpoint. |
| |
| <br><dt><code>WP_WRITE</code><a name="index-WP_005fWRITE-2775"></a><dd>Write only watchpoint. |
| |
| <br><dt><code>WP_ACCESS</code><a name="index-WP_005fACCESS-2776"></a><dd>Read/Write watchpoint. |
| </dl> |
| |
| </blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>register-breakpoint!</b><var> breakpoint<a name="index-register_002dbreakpoint_0021-2777"></a></var><br> |
| <blockquote><p>Add <var>breakpoint</var>, a <code><gdb:breakpoint></code> object, to <span class="sc">gdb</span>'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><span class="samp">valid</span></samp>’. |
| It is an error to register an already registered breakpoint. |
| The result is unspecified. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>delete-breakpoint!</b><var> breakpoint<a name="index-delete_002dbreakpoint_0021-2778"></a></var><br> |
| <blockquote><p>Remove <var>breakpoint</var> from <span class="sc">gdb</span>'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>If <var>breakpoint</var> was created from Guile with <code>make-breakpoint</code> |
| it may be re-registered with <span class="sc">gdb</span>, in which case the breakpoint |
| becomes valid again. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>breakpoints</b><var><a name="index-breakpoints-2779"></a></var><br> |
| <blockquote><p>Return a list of all breakpoints. |
| Each element of the list is a <code><gdb:breakpoint></code> object. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>breakpoint?</b><var> object<a name="index-breakpoint_003f-2780"></a></var><br> |
| <blockquote><p>Return <code>#t</code> if <var>object</var> is a <code><gdb:breakpoint></code> object, |
| and <code>#f</code> otherwise. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>breakpoint-valid?</b><var> breakpoint<a name="index-breakpoint_002dvalid_003f-2781"></a></var><br> |
| <blockquote><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 <span class="sc">gdb</span> 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></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>breakpoint-number</b><var> breakpoint<a name="index-breakpoint_002dnumber-2782"></a></var><br> |
| <blockquote><p>Return the breakpoint's number — the identifier used by |
| the user to manipulate the breakpoint. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>breakpoint-type</b><var> breakpoint<a name="index-breakpoint_002dtype-2783"></a></var><br> |
| <blockquote><p>Return the breakpoint's type — the identifier used to |
| determine the actual breakpoint type or use-case. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>breakpoint-visible?</b><var> breakpoint<a name="index-breakpoint_002dvisible_003f-2784"></a></var><br> |
| <blockquote><p>Return <code>#t</code> if the breakpoint is visible to the user |
| when hit, or when the ‘<samp><span class="samp">info breakpoints</span></samp>’ command is run. |
| Otherwise return <code>#f</code>. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>breakpoint-location</b><var> breakpoint<a name="index-breakpoint_002dlocation-2785"></a></var><br> |
| <blockquote><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></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>breakpoint-expression</b><var> breakpoint<a name="index-breakpoint_002dexpression-2786"></a></var><br> |
| <blockquote><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></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>breakpoint-enabled?</b><var> breakpoint<a name="index-breakpoint_002denabled_003f-2787"></a></var><br> |
| <blockquote><p>Return <code>#t</code> if the breakpoint is enabled, and <code>#f</code> otherwise. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>set-breakpoint-enabled!</b><var> breakpoint flag<a name="index-set_002dbreakpoint_002denabled_0021-2788"></a></var><br> |
| <blockquote><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></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>breakpoint-silent?</b><var> breakpoint<a name="index-breakpoint_002dsilent_003f-2789"></a></var><br> |
| <blockquote><p>Return <code>#t</code> if the breakpoint is silent, and <code>#f</code> otherwise. |
| |
| <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></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>set-breakpoint-silent!</b><var> breakpoint flag<a name="index-set_002dbreakpoint_002dsilent_0021-2790"></a></var><br> |
| <blockquote><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></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>breakpoint-ignore-count</b><var> breakpoint<a name="index-breakpoint_002dignore_002dcount-2791"></a></var><br> |
| <blockquote><p>Return the ignore count for <var>breakpoint</var>. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>set-breakpoint-ignore-count!</b><var> breakpoint count<a name="index-set_002dbreakpoint_002dignore_002dcount_0021-2792"></a></var><br> |
| <blockquote><p>Set the ignore count for <var>breakpoint</var> to <var>count</var>. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>breakpoint-hit-count</b><var> breakpoint<a name="index-breakpoint_002dhit_002dcount-2793"></a></var><br> |
| <blockquote><p>Return hit count of <var>breakpoint</var>. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>set-breakpoint-hit-count!</b><var> breakpoint count<a name="index-set_002dbreakpoint_002dhit_002dcount_0021-2794"></a></var><br> |
| <blockquote><p>Set the hit count of <var>breakpoint</var> to <var>count</var>. |
| At present, <var>count</var> must be zero. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>breakpoint-thread</b><var> breakpoint<a name="index-breakpoint_002dthread-2795"></a></var><br> |
| <blockquote><p>Return the global-thread-id for thread-specific breakpoint |
| <var>breakpoint</var>. Return #f if <var>breakpoint</var> is not |
| thread-specific. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>set-breakpoint-thread!</b><var> breakpoint global-thread-id|#f<a name="index-set_002dbreakpoint_002dthread_0021-2796"></a></var><br> |
| <blockquote><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></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>breakpoint-task</b><var> breakpoint<a name="index-breakpoint_002dtask-2797"></a></var><br> |
| <blockquote><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></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>set-breakpoint-task!</b><var> breakpoint task<a name="index-set_002dbreakpoint_002dtask_0021-2798"></a></var><br> |
| <blockquote><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></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>breakpoint-condition</b><var> breakpoint<a name="index-breakpoint_002dcondition-2799"></a></var><br> |
| <blockquote><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></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>set-breakpoint-condition!</b><var> breakpoint condition<a name="index-set_002dbreakpoint_002dcondition_0021-2800"></a></var><br> |
| <blockquote><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></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>breakpoint-stop</b><var> breakpoint<a name="index-breakpoint_002dstop-2801"></a></var><br> |
| <blockquote><p>Return the stop predicate of <var>breakpoint</var>. |
| See <code>set-breakpoint-stop!</code> below in this section. |
| </p></blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>set-breakpoint-stop!</b><var> breakpoint procedure|#f<a name="index-set_002dbreakpoint_002dstop_0021-2802"></a></var><br> |
| <blockquote><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>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>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 <span class="sc">gdb</span> or the inferior |
| at this time. |
| |
| <p>Example <code>stop</code> implementation: |
| |
| <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> |
| </blockquote></div> |
| |
| <div class="defun"> |
| — Scheme Procedure: <b>breakpoint-commands</b><var> breakpoint<a name="index-breakpoint_002dcommands-2803"></a></var><br> |
| <blockquote><p>Return the commands attached to <var>breakpoint</var> as a string, |
| or <code>#f</code> if there are none. |
| </p></blockquote></div> |
| |
| </body></html> |
| |
