| <!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: Line Numbers</title> |
| |
| <meta name="description" content="STABS: Line Numbers"> |
| <meta name="keywords" content="STABS: Line Numbers"> |
| <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="Program-Structure.html#Program-Structure" rel="up" title="Program Structure"> |
| <link href="Procedures.html#Procedures" rel="next" title="Procedures"> |
| <link href="Include-Files.html#Include-Files" rel="prev" title="Include Files"> |
| <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="Line-Numbers"></a> |
| <div class="header"> |
| <p> |
| Next: <a href="Procedures.html#Procedures" accesskey="n" rel="next">Procedures</a>, Previous: <a href="Include-Files.html#Include-Files" accesskey="p" rel="prev">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> |
| </div> |
| <hr> |
| <a name="Line-Numbers-1"></a> |
| <h3 class="section">2.4 Line Numbers</h3> |
| |
| <a name="index-N_005fSLINE"></a> |
| <p>An <code>N_SLINE</code> symbol represents the start of a source line. The |
| desc field contains the line number and the value contains the code |
| address for the start of that source line. On most machines the address |
| is absolute; for stabs in sections (see <a href="Stab-Sections.html#Stab-Sections">Stab Sections</a>), it is |
| relative to the function in which the <code>N_SLINE</code> symbol occurs. |
| </p> |
| <a name="index-N_005fDSLINE"></a> |
| <a name="index-N_005fBSLINE"></a> |
| <p>GNU documents <code>N_DSLINE</code> and <code>N_BSLINE</code> symbols for line |
| numbers in the data or bss segments, respectively. They are identical |
| to <code>N_SLINE</code> but are relocated differently by the linker. They |
| were intended to be used to describe the source location of a variable |
| declaration, but I believe that GCC2 actually puts the line number in |
| the desc field of the stab for the variable itself. GDB has been |
| ignoring these symbols (unless they contain a string field) since |
| at least GDB 3.5. |
| </p> |
| <p>For single source lines that generate discontiguous code, such as flow |
| of control statements, there may be more than one line number entry for |
| the same source line. In this case there is a line number entry at the |
| start of each code range, each with the same line number. |
| </p> |
| <p>XCOFF does not use stabs for line numbers. Instead, it uses COFF line |
| numbers (which are outside the scope of this document). Standard COFF |
| line numbers cannot deal with include files, but in XCOFF this is fixed |
| with the <code>C_BINCL</code> method of marking include files (see <a href="Include-Files.html#Include-Files">Include Files</a>). |
| </p> |
| |
| |
| |
| </body> |
| </html> |
