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diff --git a/share/doc/gdb/Selecting-Pretty_002dPrinters.html b/share/doc/gdb/Selecting-Pretty_002dPrinters.html new file mode 100644 index 0000000..ac3d763 --- /dev/null +++ b/share/doc/gdb/Selecting-Pretty_002dPrinters.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: Selecting Pretty-Printers</title> + +<meta name="description" content="Debugging with GDB: Selecting Pretty-Printers"> +<meta name="keywords" content="Debugging with GDB: Selecting Pretty-Printers"> +<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="Python-API.html#Python-API" rel="up" title="Python API"> +<link href="Writing-a-Pretty_002dPrinter.html#Writing-a-Pretty_002dPrinter" rel="next" title="Writing a Pretty-Printer"> +<link href="Pretty-Printing-API.html#Pretty-Printing-API" rel="previous" title="Pretty Printing API"> +<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="Selecting-Pretty_002dPrinters"></a> +<div class="header"> +<p> +Next: <a href="Writing-a-Pretty_002dPrinter.html#Writing-a-Pretty_002dPrinter" accesskey="n" rel="next">Writing a Pretty-Printer</a>, Previous: <a href="Pretty-Printing-API.html#Pretty-Printing-API" accesskey="p" rel="previous">Pretty Printing API</a>, Up: <a href="Python-API.html#Python-API" accesskey="u" rel="up">Python API</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="Selecting-Pretty_002dPrinters-1"></a> +<h4 class="subsubsection">23.3.2.6 Selecting Pretty-Printers</h4> +<a name="index-selecting-python-pretty_002dprinters"></a> + +<p><small>GDB</small> provides several ways to register a pretty-printer: +globally, per program space, and per objfile. When choosing how to +register your pretty-printer, a good rule is to register it with the +smallest scope possible: that is prefer a specific objfile first, then +a program space, and only register a printer globally as a last +resort. +</p> +<a name="index-gdb_002epretty_005fprinters"></a> +<dl> +<dt><a name="index-gdb_002epretty_005fprinters-1"></a>Variable: <strong>gdb.pretty_printers</strong></dt> +<dd><p>The Python list <code>gdb.pretty_printers</code> contains an array of +functions or callable objects that have been registered via addition +as a pretty-printer. Printers in this list are called <code>global</code> +printers, they’re available when debugging all inferiors. +</p></dd></dl> + +<p>Each <code>gdb.Progspace</code> contains a <code>pretty_printers</code> attribute. +Each <code>gdb.Objfile</code> also contains a <code>pretty_printers</code> +attribute. +</p> +<p>Each function on these lists is passed a single <code>gdb.Value</code> +argument and should return a pretty-printer object conforming to the +interface definition above (see <a href="Pretty-Printing-API.html#Pretty-Printing-API">Pretty Printing API</a>). If a function +cannot create a pretty-printer for the value, it should return +<code>None</code>. +</p> +<p><small>GDB</small> first checks the <code>pretty_printers</code> attribute of each +<code>gdb.Objfile</code> in the current program space and iteratively calls +each enabled lookup routine in the list for that <code>gdb.Objfile</code> +until it receives a pretty-printer object. +If no pretty-printer is found in the objfile lists, <small>GDB</small> then +searches the pretty-printer list of the current program space, +calling each enabled function until an object is returned. +After these lists have been exhausted, it tries the global +<code>gdb.pretty_printers</code> list, again calling each enabled function until an +object is returned. +</p> +<p>The order in which the objfiles are searched is not specified. For a +given list, functions are always invoked from the head of the list, +and iterated over sequentially until the end of the list, or a printer +object is returned. +</p> +<p>For various reasons a pretty-printer may not work. +For example, the underlying data structure may have changed and +the pretty-printer is out of date. +</p> +<p>The consequences of a broken pretty-printer are severe enough that +<small>GDB</small> provides support for enabling and disabling individual +printers. For example, if <code>print frame-arguments</code> is on, +a backtrace can become highly illegible if any argument is printed +with a broken printer. +</p> +<p>Pretty-printers are enabled and disabled by attaching an <code>enabled</code> +attribute to the registered function or callable object. If this attribute +is present and its value is <code>False</code>, the printer is disabled, otherwise +the printer is enabled. +</p> +<hr> +<div class="header"> +<p> +Next: <a href="Writing-a-Pretty_002dPrinter.html#Writing-a-Pretty_002dPrinter" accesskey="n" rel="next">Writing a Pretty-Printer</a>, Previous: <a href="Pretty-Printing-API.html#Pretty-Printing-API" accesskey="p" rel="previous">Pretty Printing API</a>, Up: <a href="Python-API.html#Python-API" accesskey="u" rel="up">Python API</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> |