visus
/
toolchain-gcc-arm-embedded
Watch 1
Star 0
Fork 0
Code Issues 0 Pull Requests 0 Releases 0 Wiki Activity
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
2 Commits
1 Branch
Tree: 898a39b5ab
Branches Tags
${ item.name }
Create branch ${ searchTerm }
from '898a39b5ab'
${ noResults }
toolchain-gcc-arm-embedded/share/doc/gcc-arm-none-eabi/html/gdb/Selecting-Pretty_002dPrinte...

140 lines
6.9KB
Raw Blame History 

  1. <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

  2. <html>

  3. <!-- Copyright (C) 1988-2020 Free Software Foundation, Inc.

  4. 

  5. Permission is granted to copy, distribute and/or modify this document

  6. under the terms of the GNU Free Documentation License, Version 1.3 or

  7. any later version published by the Free Software Foundation; with the

  8. Invariant Sections being "Free Software" and "Free Software Needs

  9. Free Documentation", with the Front-Cover Texts being "A GNU Manual,"

  10. and with the Back-Cover Texts as in (a) below.

  11. 

  12. (a) The FSF's Back-Cover Text is: "You are free to copy and modify

  13. this GNU Manual.  Buying copies from GNU Press supports the FSF in

  14. developing GNU and promoting software freedom." -->

  15. <!-- Created by GNU Texinfo 6.5, http://www.gnu.org/software/texinfo/ -->

  16. <head>

  17. <meta http-equiv="Content-Type" content="text/html; charset=utf-8">

  18. <title>Selecting Pretty-Printers (Debugging with GDB)</title>

  19. 

  20. <meta name="description" content="Selecting Pretty-Printers (Debugging with GDB)">

  21. <meta name="keywords" content="Selecting Pretty-Printers (Debugging with GDB)">

  22. <meta name="resource-type" content="document">

  23. <meta name="distribution" content="global">

  24. <meta name="Generator" content="makeinfo">

  25. <link href="index.html#Top" rel="start" title="Top">

  26. <link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index">

  27. <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">

  28. <link href="Python-API.html#Python-API" rel="up" title="Python API">

  29. <link href="Writing-a-Pretty_002dPrinter.html#Writing-a-Pretty_002dPrinter" rel="next" title="Writing a Pretty-Printer">

  30. <link href="Pretty-Printing-API.html#Pretty-Printing-API" rel="prev" title="Pretty Printing API">

  31. <style type="text/css">

  32. <!--

  33. a.summary-letter {text-decoration: none}

  34. blockquote.indentedblock {margin-right: 0em}

  35. blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}

  36. blockquote.smallquotation {font-size: smaller}

  37. div.display {margin-left: 3.2em}

  38. div.example {margin-left: 3.2em}

  39. div.lisp {margin-left: 3.2em}

  40. div.smalldisplay {margin-left: 3.2em}

  41. div.smallexample {margin-left: 3.2em}

  42. div.smalllisp {margin-left: 3.2em}

  43. kbd {font-style: oblique}

  44. pre.display {font-family: inherit}

  45. pre.format {font-family: inherit}

  46. pre.menu-comment {font-family: serif}

  47. pre.menu-preformatted {font-family: serif}

  48. pre.smalldisplay {font-family: inherit; font-size: smaller}

  49. pre.smallexample {font-size: smaller}

  50. pre.smallformat {font-family: inherit; font-size: smaller}

  51. pre.smalllisp {font-size: smaller}

  52. span.nolinebreak {white-space: nowrap}

  53. span.roman {font-family: initial; font-weight: normal}

  54. span.sansserif {font-family: sans-serif; font-weight: normal}

  55. ul.no-bullet {list-style: none}

  56. -->

  57. </style>

  58. 

  59. 

  60. </head>

  61. 

  62. <body lang="en">

  63. <a name="Selecting-Pretty_002dPrinters"></a>

  64. <div class="header">

  65. <p>

  66. 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="prev">Pretty Printing API</a>, Up: <a href="Python-API.html#Python-API" accesskey="u" rel="up">Python API</a> &nbsp; [<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>

  67. </div>

  68. <hr>

  69. <a name="Selecting-Pretty_002dPrinters-1"></a>

  70. <h4 class="subsubsection">23.2.2.6 Selecting Pretty-Printers</h4>

  71. <a name="index-selecting-python-pretty_002dprinters"></a>

  72. 

  73. <p><small>GDB</small> provides several ways to register a pretty-printer:

  74. globally, per program space, and per objfile.  When choosing how to

  75. register your pretty-printer, a good rule is to register it with the

  76. smallest scope possible: that is prefer a specific objfile first, then

  77. a program space, and only register a printer globally as a last

  78. resort.

  79. </p>

  80. <a name="index-gdb_002epretty_005fprinters"></a>

  81. <dl>

  82. <dt><a name="index-gdb_002epretty_005fprinters-1"></a>Variable: <strong>gdb.pretty_printers</strong></dt>

  83. <dd><p>The Python list <code>gdb.pretty_printers</code> contains an array of

  84. functions or callable objects that have been registered via addition

  85. as a pretty-printer.  Printers in this list are called <code>global</code>

  86. printers, they&rsquo;re available when debugging all inferiors.

  87. </p></dd></dl>

  88. 

  89. <p>Each <code>gdb.Progspace</code> contains a <code>pretty_printers</code> attribute.

  90. Each <code>gdb.Objfile</code> also contains a <code>pretty_printers</code>

  91. attribute.

  92. </p>

  93. <p>Each function on these lists is passed a single <code>gdb.Value</code>

  94. argument and should return a pretty-printer object conforming to the

  95. interface definition above (see <a href="Pretty-Printing-API.html#Pretty-Printing-API">Pretty Printing API</a>).  If a function

  96. cannot create a pretty-printer for the value, it should return

  97. <code>None</code>.

  98. </p>

  99. <p><small>GDB</small> first checks the <code>pretty_printers</code> attribute of each

  100. <code>gdb.Objfile</code> in the current program space and iteratively calls

  101. each enabled lookup routine in the list for that <code>gdb.Objfile</code>

  102. until it receives a pretty-printer object.

  103. If no pretty-printer is found in the objfile lists, <small>GDB</small> then

  104. searches the pretty-printer list of the current program space,

  105. calling each enabled function until an object is returned.

  106. After these lists have been exhausted, it tries the global

  107. <code>gdb.pretty_printers</code> list, again calling each enabled function until an

  108. object is returned.

  109. </p>

  110. <p>The order in which the objfiles are searched is not specified.  For a

  111. given list, functions are always invoked from the head of the list,

  112. and iterated over sequentially until the end of the list, or a printer

  113. object is returned.

  114. </p>

  115. <p>For various reasons a pretty-printer may not work.

  116. For example, the underlying data structure may have changed and

  117. the pretty-printer is out of date.

  118. </p>

  119. <p>The consequences of a broken pretty-printer are severe enough that

  120. <small>GDB</small> provides support for enabling and disabling individual

  121. printers.  For example, if <code>print frame-arguments</code> is on,

  122. a backtrace can become highly illegible if any argument is printed

  123. with a broken printer.

  124. </p>

  125. <p>Pretty-printers are enabled and disabled by attaching an <code>enabled</code>

  126. attribute to the registered function or callable object.  If this attribute

  127. is present and its value is <code>False</code>, the printer is disabled, otherwise

  128. the printer is enabled.

  129. </p>

  130. <hr>

  131. <div class="header">

  132. <p>

  133. 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="prev">Pretty Printing API</a>, Up: <a href="Python-API.html#Python-API" accesskey="u" rel="up">Python API</a> &nbsp; [<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>

  134. </div>

  135. 

  136. 

  137. 

  138. </body>

  139. </html>