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A copy of the license is included in the section entitled "GNU 12Free Documentation License". --> 13<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ --> 14<head> 15<title>STABS: Line Numbers</title> 16 17<meta name="description" content="STABS: Line Numbers"> 18<meta name="keywords" content="STABS: Line Numbers"> 19<meta name="resource-type" content="document"> 20<meta name="distribution" content="global"> 21<meta name="Generator" content="makeinfo"> 22<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 23<link href="index.html#Top" rel="start" title="Top"> 24<link href="Symbol-Types-Index.html#Symbol-Types-Index" rel="index" title="Symbol Types Index"> 25<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> 26<link href="Program-Structure.html#Program-Structure" rel="up" title="Program Structure"> 27<link href="Procedures.html#Procedures" rel="next" title="Procedures"> 28<link href="Include-Files.html#Include-Files" rel="previous" title="Include Files"> 29<style type="text/css"> 30<!-- 31a.summary-letter {text-decoration: none} 32blockquote.smallquotation {font-size: smaller} 33div.display {margin-left: 3.2em} 34div.example {margin-left: 3.2em} 35div.indentedblock {margin-left: 3.2em} 36div.lisp {margin-left: 3.2em} 37div.smalldisplay {margin-left: 3.2em} 38div.smallexample {margin-left: 3.2em} 39div.smallindentedblock {margin-left: 3.2em; font-size: smaller} 40div.smalllisp {margin-left: 3.2em} 41kbd {font-style:oblique} 42pre.display {font-family: inherit} 43pre.format {font-family: inherit} 44pre.menu-comment {font-family: serif} 45pre.menu-preformatted {font-family: serif} 46pre.smalldisplay {font-family: inherit; font-size: smaller} 47pre.smallexample {font-size: smaller} 48pre.smallformat {font-family: inherit; font-size: smaller} 49pre.smalllisp {font-size: smaller} 50span.nocodebreak {white-space:nowrap} 51span.nolinebreak {white-space:nowrap} 52span.roman {font-family:serif; font-weight:normal} 53span.sansserif {font-family:sans-serif; font-weight:normal} 54ul.no-bullet {list-style: none} 55--> 56</style> 57 58 59</head> 60 61<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> 62<a name="Line-Numbers"></a> 63<div class="header"> 64<p> 65Next: <a href="Procedures.html#Procedures" accesskey="n" rel="next">Procedures</a>, Previous: <a href="Include-Files.html#Include-Files" accesskey="p" rel="previous">Include Files</a>, Up: <a href="Program-Structure.html#Program-Structure" accesskey="u" rel="up">Program Structure</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> 66</div> 67<hr> 68<a name="Line-Numbers-1"></a> 69<h3 class="section">2.4 Line Numbers</h3> 70 71<a name="index-N_005fSLINE"></a> 72<p>An <code>N_SLINE</code> symbol represents the start of a source line. The 73desc field contains the line number and the value contains the code 74address for the start of that source line. On most machines the address 75is absolute; for stabs in sections (see <a href="Stab-Sections.html#Stab-Sections">Stab Sections</a>), it is 76relative to the function in which the <code>N_SLINE</code> symbol occurs. 77</p> 78<a name="index-N_005fDSLINE"></a> 79<a name="index-N_005fBSLINE"></a> 80<p>GNU documents <code>N_DSLINE</code> and <code>N_BSLINE</code> symbols for line 81numbers in the data or bss segments, respectively. They are identical 82to <code>N_SLINE</code> but are relocated differently by the linker. They 83were intended to be used to describe the source location of a variable 84declaration, but I believe that GCC2 actually puts the line number in 85the desc field of the stab for the variable itself. GDB has been 86ignoring these symbols (unless they contain a string field) since 87at least GDB 3.5. 88</p> 89<p>For single source lines that generate discontiguous code, such as flow 90of control statements, there may be more than one line number entry for 91the same source line. In this case there is a line number entry at the 92start of each code range, each with the same line number. 93</p> 94<p>XCOFF does not use stabs for line numbers. Instead, it uses COFF line 95numbers (which are outside the scope of this document). Standard COFF 96line numbers cannot deal with include files, but in XCOFF this is fixed 97with the <code>C_BINCL</code> method of marking include files (see <a href="Include-Files.html#Include-Files">Include Files</a>). 98</p> 99 100 101 102</body> 103</html> 104