lfs-book-zh_CN/chapter06/aboutdebug.xml

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN" "http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../general.ent">
  %general-entities;
]>
<sect1 id="ch-system-aboutdebug">
<title>About debugging symbols</title>
<?dbhtml filename="aboutdebug.html"?>

<para>Most programs and libraries are, by default, compiled with debugging
symbols included (with <command>gcc</command>'s <parameter>-g</parameter>
option). This means that, when debugging a program or library that was compiled
with debugging information included, the debugger can give you not only memory
addresses but also the names of the routines and variables.</para>
 
<para>The inclusion of these debugging symbols, however, enlarges a program or
library significantly. To get an idea of the amount of space these symbols
occupy, have a look at the following:</para>

<itemizedlist>

<listitem><para>a bash binary 
with debugging symbols: 1200 KB</para></listitem>

<listitem><para>a bash binary
without debugging symbols: 480 KB</para></listitem>

<listitem><para>Glibc and GCC files (<filename class="directory">/lib</filename>
and <filename class="directory">/usr/lib</filename>)
with debugging symbols: 87 MB</para></listitem>

<listitem><para>Glibc and GCC files
without debugging symbols: 16 MB</para></listitem>

</itemizedlist>

<para>Sizes may vary somewhat, depending on which compiler was used and which C
library, but when comparing programs with and without debugging symbols the
difference will generally be a factor between 2 and 5.</para>

<para>As most people will probably never use a debugger on their system
software, a lot of disk space can be regained by removing these symbols. For
your convenience, the next section shows how to strip all debugging symbols
from all programs and libraries. Information on other ways of optimizing your
system can be found in the hint at <ulink url="&hints-root;optimization.txt"/>.</para>

</sect1>