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diff --git a/share/doc/gdb/Range-Checking.html b/share/doc/gdb/Range-Checking.html new file mode 100644 index 0000000..8c74b4e --- /dev/null +++ b/share/doc/gdb/Range-Checking.html @@ -0,0 +1,140 @@ +<!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: Range Checking</title> + +<meta name="description" content="Debugging with GDB: Range Checking"> +<meta name="keywords" content="Debugging with GDB: Range Checking"> +<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="Checks.html#Checks" rel="up" title="Checks"> +<link href="Supported-Languages.html#Supported-Languages" rel="next" title="Supported Languages"> +<link href="Type-Checking.html#Type-Checking" rel="previous" title="Type Checking"> +<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="Range-Checking"></a> +<div class="header"> +<p> +Previous: <a href="Type-Checking.html#Type-Checking" accesskey="p" rel="previous">Type Checking</a>, Up: <a href="Checks.html#Checks" accesskey="u" rel="up">Checks</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="An-Overview-of-Range-Checking"></a> +<h4 class="subsection">15.3.2 An Overview of Range Checking</h4> + +<p>In some languages (such as Modula-2), it is an error to exceed the +bounds of a type; this is enforced with run-time checks. Such range +checking is meant to ensure program correctness by making sure +computations do not overflow, or indices on an array element access do +not exceed the bounds of the array. +</p> +<p>For expressions you use in <small>GDB</small> commands, you can tell +<small>GDB</small> to treat range errors in one of three ways: ignore them, +always treat them as errors and abandon the expression, or issue +warnings but evaluate the expression anyway. +</p> +<p>A range error can result from numerical overflow, from exceeding an +array index bound, or when you type a constant that is not a member +of any type. Some languages, however, do not treat overflows as an +error. In many implementations of C, mathematical overflow causes the +result to “wrap around” to lower values—for example, if <var>m</var> is +the largest integer value, and <var>s</var> is the smallest, then +</p> +<div class="smallexample"> +<pre class="smallexample"><var>m</var> + 1 ⇒ <var>s</var> +</pre></div> + +<p>This, too, is specific to individual languages, and in some cases +specific to individual compilers or machines. See <a href="Supported-Languages.html#Supported-Languages">Supported Languages</a>, for further details on specific languages. +</p> +<p><small>GDB</small> provides some additional commands for controlling the range checker: +</p> +<a name="index-set-check-range"></a> +<a name="index-show-check-range"></a> +<dl compact="compact"> +<dt><code>set check range auto</code></dt> +<dd><p>Set range checking on or off based on the current working language. +See <a href="Supported-Languages.html#Supported-Languages">Supported Languages</a>, for the default settings for +each language. +</p> +</dd> +<dt><code>set check range on</code></dt> +<dt><code>set check range off</code></dt> +<dd><p>Set range checking on or off, overriding the default setting for the +current working language. A warning is issued if the setting does not +match the language default. If a range error occurs and range checking is on, +then a message is printed and evaluation of the expression is aborted. +</p> +</dd> +<dt><code>set check range warn</code></dt> +<dd><p>Output messages when the <small>GDB</small> range checker detects a range error, +but attempt to evaluate the expression anyway. Evaluating the +expression may still be impossible for other reasons, such as accessing +memory that the process does not own (a typical example from many Unix +systems). +</p> +</dd> +<dt><code>show check range</code></dt> +<dd><p>Show the current setting of the range checker, and whether or not it is +being set automatically by <small>GDB</small>. +</p></dd> +</dl> + +<hr> +<div class="header"> +<p> +Previous: <a href="Type-Checking.html#Type-Checking" accesskey="p" rel="previous">Type Checking</a>, Up: <a href="Checks.html#Checks" accesskey="u" rel="up">Checks</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> |