aarch64-linux-gnu-4.9/share/doc/gdb/stabs/Enumerations.html - toolchains/linux-x86/gcc - Git at Google

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 <html>
 <!-- Copyright (C) 1992-2015 Free Software Foundation, Inc.
 Contributed by Cygnus Support.  Written by Julia Menapace, Jim Kingdon,
 and David MacKenzie.

 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 5.2, http://www.gnu.org/software/texinfo/ -->
 <head>
 <title>STABS: Enumerations</title>

 <meta name="description" content="STABS: Enumerations">
 <meta name="keywords" content="STABS: Enumerations">
 <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="Symbol-Types-Index.html#Symbol-Types-Index" rel="index" title="Symbol Types Index">
 <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
 <link href="Types.html#Types" rel="up" title="Types">
 <link href="Structures.html#Structures" rel="next" title="Structures">
 <link href="Strings.html#Strings" rel="prev" title="Strings">
 <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="Enumerations"></a>
 <div class="header">
 <p>
 Next: <a href="Structures.html#Structures" accesskey="n" rel="next">Structures</a>, Previous: <a href="Strings.html#Strings" accesskey="p" rel="prev">Strings</a>, Up: <a href="Types.html#Types" accesskey="u" rel="up">Types</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Symbol-Types-Index.html#Symbol-Types-Index" title="Index" rel="index">Index</a>]</p>
 </div>
 <hr>
 <a name="Enumerations-1"></a>
 <h3 class="section">5.7 Enumerations</h3>

 <p>Enumerations are defined with the &lsquo;<samp>e</samp>&rsquo; type descriptor.
 </p>
 <p>The source line below declares an enumeration type at file scope.
 The type definition is located after the <code>N_RBRAC</code> that marks the end of
 the previous procedure&rsquo;s block scope, and before the <code>N_FUN</code> that marks
 the beginning of the next procedure&rsquo;s block scope.  Therefore it does not
 describe a block local symbol, but a file local one.
 </p>
 <p>The source line:
 </p>
 <div class="example">
 <pre class="example">enum e_places {first,second=3,last};
 </pre></div>

 <p>generates the following stab:
 </p>
 <div class="example">
 <pre class="example">.stabs &quot;e_places:T22=efirst:0,second:3,last:4,;&quot;,128,0,0,0
 </pre></div>

 <p>The symbol descriptor (&lsquo;<samp>T</samp>&rsquo;) says that the stab describes a
 structure, enumeration, or union tag.  The type descriptor &lsquo;<samp>e</samp>&rsquo;,
 following the &lsquo;<samp>22=</samp>&rsquo; of the type definition narrows it down to an
 enumeration type.  Following the &lsquo;<samp>e</samp>&rsquo; is a list of the elements of
 the enumeration.  The format is &lsquo;<samp><var>name</var>:<var>value</var>,</samp>&rsquo;.  The
 list of elements ends with &lsquo;<samp>;</samp>&rsquo;.  The fact that <var>value</var> is
 specified as an integer can cause problems if the value is large.  GCC
 2.5.2 tries to output it in octal in that case with a leading zero,
 which is probably a good thing, although GDB 4.11 supports octal only in
 cases where decimal is perfectly good.  Negative decimal values are
 supported by both GDB and dbx.
 </p>
 <p>There is no standard way to specify the size of an enumeration type; it
 is determined by the architecture (normally all enumerations types are
 32 bits).  Type attributes can be used to specify an enumeration type of
 another size for debuggers which support them; see <a href="String-Field.html#String-Field">String Field</a>.
 </p>
 <p>Enumeration types are unusual in that they define symbols for the
 enumeration values (<code>first</code>, <code>second</code>, and <code>third</code> in the
 above example), and even though these symbols are visible in the file as
 a whole (rather than being in a more local namespace like structure
 member names), they are defined in the type definition for the
 enumeration type rather than each having their own symbol.  In order to
 be fast, GDB will only get symbols from such types (in its initial scan
 of the stabs) if the type is the first thing defined after a &lsquo;<samp>T</samp>&rsquo; or
 &lsquo;<samp>t</samp>&rsquo; symbol descriptor (the above example fulfills this
 requirement).  If the type does not have a name, the compiler should
 emit it in a nameless stab (see <a href="String-Field.html#String-Field">String Field</a>); GCC does this.
 </p>
 <hr>
 <div class="header">
 <p>
 Next: <a href="Structures.html#Structures" accesskey="n" rel="next">Structures</a>, Previous: <a href="Strings.html#Strings" accesskey="p" rel="prev">Strings</a>, Up: <a href="Types.html#Types" accesskey="u" rel="up">Types</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Symbol-Types-Index.html#Symbol-Types-Index" title="Index" rel="index">Index</a>]</p>
 </div>


 </body>
 </html>
	<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
	<html>
	<!-- Copyright (C) 1992-2015 Free Software Foundation, Inc.
	Contributed by Cygnus Support. Written by Julia Menapace, Jim Kingdon,
	and David MacKenzie.

	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 5.2, http://www.gnu.org/software/texinfo/ -->
	<head>
	<title>STABS: Enumerations</title>

	<meta name="description" content="STABS: Enumerations">
	<meta name="keywords" content="STABS: Enumerations">
	<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="Symbol-Types-Index.html#Symbol-Types-Index" rel="index" title="Symbol Types Index">
	<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
	<link href="Types.html#Types" rel="up" title="Types">
	<link href="Structures.html#Structures" rel="next" title="Structures">
	<link href="Strings.html#Strings" rel="prev" title="Strings">
	<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="Enumerations"></a>
	<div class="header">
	<p>
	Next: <a href="Structures.html#Structures" accesskey="n" rel="next">Structures</a>, Previous: <a href="Strings.html#Strings" accesskey="p" rel="prev">Strings</a>, Up: <a href="Types.html#Types" accesskey="u" rel="up">Types</a>   [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Symbol-Types-Index.html#Symbol-Types-Index" title="Index" rel="index">Index</a>]</p>
	</div>
	<hr>
	<a name="Enumerations-1"></a>
	<h3 class="section">5.7 Enumerations</h3>

	<p>Enumerations are defined with the ‘<samp>e</samp>’ type descriptor.
	</p>
	<p>The source line below declares an enumeration type at file scope.
	The type definition is located after the <code>N_RBRAC</code> that marks the end of
	the previous procedure’s block scope, and before the <code>N_FUN</code> that marks
	the beginning of the next procedure’s block scope. Therefore it does not
	describe a block local symbol, but a file local one.
	</p>
	<p>The source line:
	</p>
	<div class="example">
	<pre class="example">enum e_places {first,second=3,last};
	</pre></div>

	<p>generates the following stab:
	</p>
	<div class="example">
	<pre class="example">.stabs "e_places:T22=efirst:0,second:3,last:4,;",128,0,0,0
	</pre></div>

	<p>The symbol descriptor (‘<samp>T</samp>’) says that the stab describes a
	structure, enumeration, or union tag. The type descriptor ‘<samp>e</samp>’,
	following the ‘<samp>22=</samp>’ of the type definition narrows it down to an
	enumeration type. Following the ‘<samp>e</samp>’ is a list of the elements of
	the enumeration. The format is ‘<samp><var>name</var>:<var>value</var>,</samp>’. The
	list of elements ends with ‘<samp>;</samp>’. The fact that <var>value</var> is
	specified as an integer can cause problems if the value is large. GCC
	2.5.2 tries to output it in octal in that case with a leading zero,
	which is probably a good thing, although GDB 4.11 supports octal only in
	cases where decimal is perfectly good. Negative decimal values are
	supported by both GDB and dbx.
	</p>
	<p>There is no standard way to specify the size of an enumeration type; it
	is determined by the architecture (normally all enumerations types are
	32 bits). Type attributes can be used to specify an enumeration type of
	another size for debuggers which support them; see <a href="String-Field.html#String-Field">String Field</a>.
	</p>
	<p>Enumeration types are unusual in that they define symbols for the
	enumeration values (<code>first</code>, <code>second</code>, and <code>third</code> in the
	above example), and even though these symbols are visible in the file as
	a whole (rather than being in a more local namespace like structure
	member names), they are defined in the type definition for the
	enumeration type rather than each having their own symbol. In order to
	be fast, GDB will only get symbols from such types (in its initial scan
	of the stabs) if the type is the first thing defined after a ‘<samp>T</samp>’ or
	‘<samp>t</samp>’ symbol descriptor (the above example fulfills this
	requirement). If the type does not have a name, the compiler should
	emit it in a nameless stab (see <a href="String-Field.html#String-Field">String Field</a>); GCC does this.
	</p>
	<hr>
	<div class="header">
	<p>
	Next: <a href="Structures.html#Structures" accesskey="n" rel="next">Structures</a>, Previous: <a href="Strings.html#Strings" accesskey="p" rel="prev">Strings</a>, Up: <a href="Types.html#Types" accesskey="u" rel="up">Types</a>   [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Symbol-Types-Index.html#Symbol-Types-Index" title="Index" rel="index">Index</a>]</p>
	</div>



	</body>
	</html>