RT-Thread-Studio
/
sdk-toolchain-GNU-ARM-Embedded
mirror of https://github-proxy.rt-thread.io/RT-Thread-Studio/sdk-toolchain-GNU-ARM-Embedded.git

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<!-- Copyright (C) 1994-2023 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 no
Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
Texts.  A copy of the license is included in the section entitled "GNU
Free Documentation License". -->
<!-- Created by GNU Texinfo 6.7, http://www.gnu.org/software/texinfo/ -->
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Value Annotations (GDB&rsquo;s Obsolete Annotations)</title>

<meta name="description" content="Value Annotations (GDB&rsquo;s Obsolete Annotations)">
<meta name="keywords" content="Value Annotations (GDB&rsquo;s Obsolete Annotations)">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="makeinfo">
<link href="index.html" rel="start" title="Top">
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
<link href="index.html" rel="up" title="Top">
<link href="Frame-Annotations.html" rel="next" title="Frame Annotations">
<link href="Server-Prefix.html" rel="prev" title="Server Prefix">
<style type="text/css">
<!--
a.summary-letter {text-decoration: none}
blockquote.indentedblock {margin-right: 0em}
div.display {margin-left: 3.2em}
div.example {margin-left: 3.2em}
div.lisp {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}
span.nolinebreak {white-space: nowrap}
span.roman {font-family: initial; font-weight: normal}
span.sansserif {font-family: sans-serif; font-weight: normal}
ul.no-bullet {list-style: none}
-->
</style>


</head>

<body lang="en">
<span id="Value-Annotations"></span><div class="header">
<p>
Next: <a href="Frame-Annotations.html" accesskey="n" rel="next">Frame Annotations</a>, Previous: <a href="Server-Prefix.html" accesskey="p" rel="prev">Server Prefix</a>, Up: <a href="index.html" accesskey="u" rel="up">Top</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p>
</div>
<hr>
<span id="Values"></span><h2 class="chapter">5 Values</h2>

<p><em>Value Annotations have been removed.  <small>GDB/MI</small> instead provides
Variable Objects.</em>
</p>
<span id="index-annotations-for-values"></span>
<p>When a value is printed in various contexts, <small>GDB</small> uses
annotations to delimit the value from the surrounding text.
</p>
<span id="index-value_002dhistory_002dbegin"></span>
<span id="index-value_002dhistory_002dvalue"></span>
<span id="index-value_002dhistory_002dend"></span>
<p>If a value is printed using <code>print</code> and added to the value history,
the annotation looks like
</p>
<div class="example">
<pre class="example">^Z^Zvalue-history-begin <var>history-number</var> <var>value-flags</var>
<var>history-string</var>
^Z^Zvalue-history-value
<var>the-value</var>
^Z^Zvalue-history-end
</pre></div>

<p>where <var>history-number</var> is the number it is getting in the value
history, <var>history-string</var> is a string, such as &lsquo;<samp>$5 = </samp>&rsquo;, which
introduces the value to the user, <var>the-value</var> is the output
corresponding to the value itself, and <var>value-flags</var> is &lsquo;<samp>*</samp>&rsquo; for
a value which can be dereferenced and &lsquo;<samp>-</samp>&rsquo; for a value which cannot.
</p>
<span id="index-value_002dbegin"></span>
<span id="index-value_002dend"></span>
<p>If the value is not added to the value history (it is an invalid float
or it is printed with the <code>output</code> command), the annotation is similar:
</p>
<div class="example">
<pre class="example">^Z^Zvalue-begin <var>value-flags</var>
<var>the-value</var>
^Z^Zvalue-end
</pre></div>

<span id="index-arg_002dbegin"></span>
<span id="index-arg_002dname_002dend"></span>
<span id="index-arg_002dvalue"></span>
<span id="index-arg_002dend"></span>
<p>When <small>GDB</small> prints an argument to a function (for example, in the output
from the <code>backtrace</code> command), it annotates it as follows:
</p>
<div class="example">
<pre class="example">^Z^Zarg-begin
<var>argument-name</var>
^Z^Zarg-name-end
<var>separator-string</var>
^Z^Zarg-value <var>value-flags</var>
<var>the-value</var>
^Z^Zarg-end
</pre></div>

<p>where <var>argument-name</var> is the name of the argument,
<var>separator-string</var> is text which separates the name from the value
for the user&rsquo;s benefit (such as &lsquo;<samp>=</samp>&rsquo;), and <var>value-flags</var> and
<var>the-value</var> have the same meanings as in a
<code>value-history-begin</code> annotation.
</p>
<span id="index-field_002dbegin"></span>
<span id="index-field_002dname_002dend"></span>
<span id="index-field_002dvalue"></span>
<span id="index-field_002dend"></span>
<p>When printing a structure, <small>GDB</small> annotates it as follows:
</p>
<div class="example">
<pre class="example">^Z^Zfield-begin <var>value-flags</var>
<var>field-name</var>
^Z^Zfield-name-end
<var>separator-string</var>
^Z^Zfield-value
<var>the-value</var>
^Z^Zfield-end
</pre></div>

<p>where <var>field-name</var> is the name of the field, <var>separator-string</var>
is text which separates the name from the value for the user&rsquo;s benefit
(such as &lsquo;<samp>=</samp>&rsquo;), and <var>value-flags</var> and <var>the-value</var> have the
same meanings as in a <code>value-history-begin</code> annotation.
</p>
<p>When printing an array, <small>GDB</small> annotates it as follows:
</p>
<div class="example">
<pre class="example">^Z^Zarray-section-begin <var>array-index</var> <var>value-flags</var>
</pre></div>

<p>where <var>array-index</var> is the index of the first element being
annotated and <var>value-flags</var> has the same meaning as in a
<code>value-history-begin</code> annotation.  This is followed by any number
of elements, where is element can be either a single element:
</p>
<span id="index-elt"></span>
<div class="example">
<pre class="example">&lsquo;<samp>,</samp>&rsquo; <var>whitespace</var>         ; <span class="roman">omitted for the first element</span>
<var>the-value</var>
^Z^Zelt
</pre></div>

<p>or a repeated element
</p>
<span id="index-elt_002drep"></span>
<span id="index-elt_002drep_002dend"></span>
<div class="example">
<pre class="example">&lsquo;<samp>,</samp>&rsquo; <var>whitespace</var>         ; <span class="roman">omitted for the first element</span>
<var>the-value</var>
^Z^Zelt-rep <var>number-of-repetitions</var>
<var>repetition-string</var>
^Z^Zelt-rep-end
</pre></div>

<p>In both cases, <var>the-value</var> is the output for the value of the
element and <var>whitespace</var> can contain spaces, tabs, and newlines.  In
the repeated case, <var>number-of-repetitions</var> is the number of
consecutive array elements which contain that value, and
<var>repetition-string</var> is a string which is designed to convey to the
user that repetition is being depicted.
</p>
<span id="index-array_002dsection_002dend"></span>
<p>Once all the array elements have been output, the array annotation is
ended with
</p>
<div class="example">
<pre class="example">^Z^Zarray-section-end
</pre></div>

<hr>
<div class="header">
<p>
Next: <a href="Frame-Annotations.html" accesskey="n" rel="next">Frame Annotations</a>, Previous: <a href="Server-Prefix.html" accesskey="p" rel="prev">Server Prefix</a>, Up: <a href="index.html" accesskey="u" rel="up">Top</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p>
</div>


</body>
</html>