You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
187 lines
8.5 KiB
HTML
187 lines
8.5 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
|
<html>
|
|
<!-- 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." -->
|
|
<!-- Created by GNU Texinfo 6.4, http://www.gnu.org/software/texinfo/ -->
|
|
<head>
|
|
<title>Additions to Ada (Debugging with GDB)</title>
|
|
|
|
<meta name="description" content="Additions to Ada (Debugging with GDB)">
|
|
<meta name="keywords" content="Additions to Ada (Debugging with GDB)">
|
|
<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="Ada.html#Ada" rel="up" title="Ada">
|
|
<link href="Overloading-support-for-Ada.html#Overloading-support-for-Ada" rel="next" title="Overloading support for Ada">
|
|
<link href="Omissions-from-Ada.html#Omissions-from-Ada" rel="prev" title="Omissions from Ada">
|
|
<style type="text/css">
|
|
<!--
|
|
a.summary-letter {text-decoration: none}
|
|
blockquote.indentedblock {margin-right: 0em}
|
|
blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
|
|
blockquote.smallquotation {font-size: smaller}
|
|
div.display {margin-left: 3.2em}
|
|
div.example {margin-left: 3.2em}
|
|
div.lisp {margin-left: 3.2em}
|
|
div.smalldisplay {margin-left: 3.2em}
|
|
div.smallexample {margin-left: 3.2em}
|
|
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.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">
|
|
<a name="Additions-to-Ada"></a>
|
|
<div class="header">
|
|
<p>
|
|
Next: <a href="Overloading-support-for-Ada.html#Overloading-support-for-Ada" accesskey="n" rel="next">Overloading support for Ada</a>, Previous: <a href="Omissions-from-Ada.html#Omissions-from-Ada" accesskey="p" rel="prev">Omissions from Ada</a>, Up: <a href="Ada.html#Ada" accesskey="u" rel="up">Ada</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="Additions-to-Ada-1"></a>
|
|
<h4 class="subsubsection">15.4.10.3 Additions to Ada</h4>
|
|
<a name="index-Ada_002c-deviations-from"></a>
|
|
|
|
<p>As it does for other languages, <small>GDB</small> makes certain generic
|
|
extensions to Ada (see <a href="Expressions.html#Expressions">Expressions</a>):
|
|
</p>
|
|
<ul>
|
|
<li> If the expression <var>E</var> is a variable residing in memory (typically
|
|
a local variable or array element) and <var>N</var> is a positive integer,
|
|
then <code><var>E</var>@<var>N</var></code> displays the values of <var>E</var> and the
|
|
<var>N</var>-1 adjacent variables following it in memory as an array. In
|
|
Ada, this operator is generally not necessary, since its prime use is
|
|
in displaying parts of an array, and slicing will usually do this in
|
|
Ada. However, there are occasional uses when debugging programs in
|
|
which certain debugging information has been optimized away.
|
|
|
|
</li><li> <code><var>B</var>::<var>var</var></code> means “the variable named <var>var</var> that
|
|
appears in function or file <var>B</var>.” When <var>B</var> is a file name,
|
|
you must typically surround it in single quotes.
|
|
|
|
</li><li> The expression <code>{<var>type</var>} <var>addr</var></code> means “the variable of type
|
|
<var>type</var> that appears at address <var>addr</var>.”
|
|
|
|
</li><li> A name starting with ‘<samp>$</samp>’ is a convenience variable
|
|
(see <a href="Convenience-Vars.html#Convenience-Vars">Convenience Vars</a>) or a machine register (see <a href="Registers.html#Registers">Registers</a>).
|
|
</li></ul>
|
|
|
|
<p>In addition, <small>GDB</small> provides a few other shortcuts and outright
|
|
additions specific to Ada:
|
|
</p>
|
|
<ul>
|
|
<li> The assignment statement is allowed as an expression, returning
|
|
its right-hand operand as its value. Thus, you may enter
|
|
|
|
<div class="smallexample">
|
|
<pre class="smallexample">(gdb) set x := y + 3
|
|
(gdb) print A(tmp := y + 1)
|
|
</pre></div>
|
|
|
|
</li><li> The semicolon is allowed as an “operator,” returning as its value
|
|
the value of its right-hand operand.
|
|
This allows, for example,
|
|
complex conditional breaks:
|
|
|
|
<div class="smallexample">
|
|
<pre class="smallexample">(gdb) break f
|
|
(gdb) condition 1 (report(i); k += 1; A(k) > 100)
|
|
</pre></div>
|
|
|
|
</li><li> Rather than use catenation and symbolic character names to introduce special
|
|
characters into strings, one may instead use a special bracket notation,
|
|
which is also used to print strings. A sequence of characters of the form
|
|
‘<samp>["<var>XX</var>"]</samp>’ within a string or character literal denotes the
|
|
(single) character whose numeric encoding is <var>XX</var> in hexadecimal. The
|
|
sequence of characters ‘<samp>["""]</samp>’ also denotes a single quotation mark
|
|
in strings. For example,
|
|
<div class="smallexample">
|
|
<pre class="smallexample"> "One line.["0a"]Next line.["0a"]"
|
|
</pre></div>
|
|
<p>contains an ASCII newline character (<code>Ada.Characters.Latin_1.LF</code>)
|
|
after each period.
|
|
</p>
|
|
</li><li> The subtype used as a prefix for the attributes <tt>'Pos</tt>, <tt>'Min</tt>, and
|
|
<tt>'Max</tt> is optional (and is ignored in any case). For example, it is valid
|
|
to write
|
|
|
|
<div class="smallexample">
|
|
<pre class="smallexample">(gdb) print 'max(x, y)
|
|
</pre></div>
|
|
|
|
</li><li> When printing arrays, <small>GDB</small> uses positional notation when the
|
|
array has a lower bound of 1, and uses a modified named notation otherwise.
|
|
For example, a one-dimensional array of three integers with a lower bound
|
|
of 3 might print as
|
|
|
|
<div class="smallexample">
|
|
<pre class="smallexample">(3 => 10, 17, 1)
|
|
</pre></div>
|
|
|
|
<p>That is, in contrast to valid Ada, only the first component has a <code>=></code>
|
|
clause.
|
|
</p>
|
|
</li><li> You may abbreviate attributes in expressions with any unique,
|
|
multi-character subsequence of
|
|
their names (an exact match gets preference).
|
|
For example, you may use <tt>a'len</tt>, <tt>a'gth</tt>, or <tt>a'lh</tt>
|
|
in place of <tt>a'length</tt>.
|
|
|
|
</li><li> <a name="index-quoting-Ada-internal-identifiers"></a>
|
|
Since Ada is case-insensitive, the debugger normally maps identifiers you type
|
|
to lower case. The GNAT compiler uses upper-case characters for
|
|
some of its internal identifiers, which are normally of no interest to users.
|
|
For the rare occasions when you actually have to look at them,
|
|
enclose them in angle brackets to avoid the lower-case mapping.
|
|
For example,
|
|
<div class="smallexample">
|
|
<pre class="smallexample">(gdb) print <JMPBUF_SAVE>[0]
|
|
</pre></div>
|
|
|
|
</li><li> Printing an object of class-wide type or dereferencing an
|
|
access-to-class-wide value will display all the components of the object’s
|
|
specific type (as indicated by its run-time tag). Likewise, component
|
|
selection on such a value will operate on the specific type of the
|
|
object.
|
|
|
|
</li></ul>
|
|
|
|
<hr>
|
|
<div class="header">
|
|
<p>
|
|
Next: <a href="Overloading-support-for-Ada.html#Overloading-support-for-Ada" accesskey="n" rel="next">Overloading support for Ada</a>, Previous: <a href="Omissions-from-Ada.html#Omissions-from-Ada" accesskey="p" rel="prev">Omissions from Ada</a>, Up: <a href="Ada.html#Ada" accesskey="u" rel="up">Ada</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>
|