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diff --git a/share/doc/gdb/Hooks.html b/share/doc/gdb/Hooks.html new file mode 100644 index 0000000..7196249 --- /dev/null +++ b/share/doc/gdb/Hooks.html @@ -0,0 +1,160 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- Copyright (C) 1988-2023 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: Hooks</title> + +<meta name="description" content="Debugging with GDB: Hooks"> +<meta name="keywords" content="Debugging with GDB: Hooks"> +<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="Sequences.html#Sequences" rel="up" title="Sequences"> +<link href="Command-Files.html#Command-Files" rel="next" title="Command Files"> +<link href="Define.html#Define" rel="previous" title="Define"> +<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="Hooks"></a> +<div class="header"> +<p> +Next: <a href="Command-Files.html#Command-Files" accesskey="n" rel="next">Command Files</a>, Previous: <a href="Define.html#Define" accesskey="p" rel="previous">Define</a>, Up: <a href="Sequences.html#Sequences" accesskey="u" rel="up">Sequences</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="User_002ddefined-Command-Hooks"></a> +<h4 class="subsection">23.1.2 User-defined Command Hooks</h4> +<a name="index-command-hooks"></a> +<a name="index-hooks_002c-for-commands"></a> +<a name="index-hooks_002c-pre_002dcommand"></a> + +<a name="index-hook"></a> +<p>You may define <em>hooks</em>, which are a special kind of user-defined +command. Whenever you run the command ‘<samp>foo</samp>’, if the user-defined +command ‘<samp>hook-foo</samp>’ exists, it is executed (with no arguments) +before that command. +</p> +<a name="index-hooks_002c-post_002dcommand"></a> +<a name="index-hookpost"></a> +<p>A hook may also be defined which is run after the command you executed. +Whenever you run the command ‘<samp>foo</samp>’, if the user-defined command +‘<samp>hookpost-foo</samp>’ exists, it is executed (with no arguments) after +that command. Post-execution hooks may exist simultaneously with +pre-execution hooks, for the same command. +</p> +<p>It is valid for a hook to call the command which it hooks. If this +occurs, the hook is not re-executed, thereby avoiding infinite recursion. +</p> + +<a name="index-stop_002c-a-pseudo_002dcommand"></a> +<p>In addition, a pseudo-command, ‘<samp>stop</samp>’ exists. Defining +(‘<samp>hook-stop</samp>’) makes the associated commands execute every time +execution stops in your program: before breakpoint commands are run, +displays are printed, or the stack frame is printed. +</p> +<p>For example, to ignore <code>SIGALRM</code> signals while +single-stepping, but treat them normally during normal execution, +you could define: +</p> +<div class="smallexample"> +<pre class="smallexample">define hook-stop +handle SIGALRM nopass +end + +define hook-run +handle SIGALRM pass +end + +define hook-continue +handle SIGALRM pass +end +</pre></div> + +<p>As a further example, to hook at the beginning and end of the <code>echo</code> +command, and to add extra text to the beginning and end of the message, +you could define: +</p> +<div class="smallexample"> +<pre class="smallexample">define hook-echo +echo <<<--- +end + +define hookpost-echo +echo --->>>\n +end + +(gdb) echo Hello World +<<<---Hello World--->>> +(gdb) + +</pre></div> + +<p>You can define a hook for any single-word command in <small>GDB</small>, but +not for command aliases; you should define a hook for the basic command +name, e.g. <code>backtrace</code> rather than <code>bt</code>. +You can hook a multi-word command by adding <code>hook-</code> or +<code>hookpost-</code> to the last word of the command, e.g. +‘<samp>define target hook-remote</samp>’ to add a hook to ‘<samp>target remote</samp>’. +</p> +<p>If an error occurs during the execution of your hook, execution of +<small>GDB</small> commands stops and <small>GDB</small> issues a prompt +(before the command that you actually typed had a chance to run). +</p> +<p>If you try to define a hook which does not match any known command, you +get a warning from the <code>define</code> command. +</p> +<hr> +<div class="header"> +<p> +Next: <a href="Command-Files.html#Command-Files" accesskey="n" rel="next">Command Files</a>, Previous: <a href="Define.html#Define" accesskey="p" rel="previous">Define</a>, Up: <a href="Sequences.html#Sequences" accesskey="u" rel="up">Sequences</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> |