toolchain/share/doc/gdb/Invoking-GDB.html

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<h3 class="section">2.1 Invoking <span class="sc">gdb</span></h3>
<p>Invoke <span class="sc">gdb</span> by running the program <code>gdb</code>. Once started,
<span class="sc">gdb</span> reads commands from the terminal until you tell it to exit.
<p>You can also run <code>gdb</code> with a variety of arguments and options,
to specify more of your debugging environment at the outset.
<p>The command-line options described here are designed
to cover a variety of situations; in some environments, some of these
options may effectively be unavailable.
<p>The most usual way to start <span class="sc">gdb</span> is with one argument,
specifying an executable program:
<pre class="smallexample"> gdb <var>program</var>
</pre>
<p class="noindent">You can also start with both an executable program and a core file
specified:
<pre class="smallexample"> gdb <var>program</var> <var>core</var>
</pre>
<p>You can, instead, specify a process ID as a second argument, if you want
to debug a running process:
<pre class="smallexample"> gdb <var>program</var> 1234
</pre>
<p class="noindent">would attach <span class="sc">gdb</span> to process <code>1234</code> (unless you also have a file
named <samp><span class="file">1234</span></samp>; <span class="sc">gdb</span> does check for a core file first).
<p>Taking advantage of the second command-line argument requires a fairly
complete operating system; when you use <span class="sc">gdb</span> as a remote
debugger attached to a bare board, there may not be any notion of
&ldquo;process&rdquo;, and there is often no way to get a core dump. <span class="sc">gdb</span>
will warn you if it is unable to attach or to read core dumps.
<p>You can optionally have <code>gdb</code> pass any arguments after the
executable file to the inferior using <code>--args</code>. This option stops
option processing.
<pre class="smallexample"> gdb --args gcc -O2 -c foo.c
</pre>
<p>This will cause <code>gdb</code> to debug <code>gcc</code>, and to set
<code>gcc</code>'s command-line arguments (see <a href="Arguments.html#Arguments">Arguments</a>) to &lsquo;<samp><span class="samp">-O2 -c foo.c</span></samp>&rsquo;.
<p>You can run <code>gdb</code> without printing the front material, which describes
<span class="sc">gdb</span>'s non-warranty, by specifying <code>--silent</code>
(or <code>-q</code>/<code>--quiet</code>):
<pre class="smallexample"> gdb --silent
</pre>
<p class="noindent">You can further control how <span class="sc">gdb</span> starts up by using command-line
options. <span class="sc">gdb</span> itself can remind you of the options available.
<p class="noindent">Type
<pre class="smallexample"> gdb -help
</pre>
<p class="noindent">to display all available options and briefly describe their use
(&lsquo;<samp><span class="samp">gdb -h</span></samp>&rsquo; is a shorter equivalent).
<p>All options and command line arguments you give are processed
in sequential order. The order makes a difference when the
&lsquo;<samp><span class="samp">-x</span></samp>&rsquo; option is used.
<ul class="menu">
<li><a accesskey="1" href="File-Options.html#File-Options">File Options</a>: Choosing files
<li><a accesskey="2" href="Mode-Options.html#Mode-Options">Mode Options</a>: Choosing modes
<li><a accesskey="3" href="Startup.html#Startup">Startup</a>: What <span class="sc">gdb</span> does during startup
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