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<h3 class="section">15.1 Switching Between Source Languages</h3>

<p>There are two ways to control the working language&mdash;either have <span class="sc">gdb</span>
set it automatically, or select it manually yourself.  You can use the
<code>set language</code> command for either purpose.  On startup, <span class="sc">gdb</span>
defaults to setting the language automatically.  The working language is
used to determine how expressions you type are interpreted, how values
are printed, etc.

   <p>In addition to the working language, every source file that
<span class="sc">gdb</span> knows about has its own working language.  For some object
file formats, the compiler might indicate which language a particular
source file is in.  However, most of the time <span class="sc">gdb</span> infers the
language from the name of the file.  The language of a source file
controls whether C<tt>++</tt> names are demangled&mdash;this way <code>backtrace</code> can
show each frame appropriately for its own language.  There is no way to
set the language of a source file from within <span class="sc">gdb</span>, but you can
set the language associated with a filename extension.  See <a href="Show.html#Show">Displaying the Language</a>.

   <p>This is most commonly a problem when you use a program, such
as <code>cfront</code> or <code>f2c</code>, that generates C but is written in
another language.  In that case, make the
program use <code>#line</code> directives in its C output; that way
<span class="sc">gdb</span> will know the correct language of the source code of the original
program, and will display that source code, not the generated C code.

<ul class="menu">
<li><a accesskey="1" href="Filenames.html#Filenames">Filenames</a>:                    Filename extensions and languages. 
<li><a accesskey="2" href="Manually.html#Manually">Manually</a>:                     Setting the working language manually
<li><a accesskey="3" href="Automatically.html#Automatically">Automatically</a>:                Having <span class="sc">gdb</span> infer the source language
</ul>

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