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<a name="system-1"></a>
<h4 class="unnumberedsubsubsec">system</h4>
<a name="index-system_002c-file_002di_002fo-system-call"></a>

<dl compact="compact">
<dt>Synopsis:</dt>
<dd><div class="smallexample">
<pre class="smallexample">int system(const char *command);
</pre></div>

</dd>
<dt>Request:</dt>
<dd><p>&lsquo;<samp>Fsystem,<var>commandptr</var>/<var>len</var></samp>&rsquo;
</p>
</dd>
<dt>Return value:</dt>
<dd><p>If <var>len</var> is zero, the return value indicates whether a shell is
available.  A zero return value indicates a shell is not available.
For non-zero <var>len</var>, the value returned is -1 on error and the
return status of the command otherwise.  Only the exit status of the
command is returned, which is extracted from the host&rsquo;s <code>system</code>
return value by calling <code>WEXITSTATUS(retval)</code>.  In case
<samp>/bin/sh</samp> could not be executed, 127 is returned.
</p>
</dd>
<dt>Errors:</dt>
<dd>
<dl compact="compact">
<dt><code>EINTR</code></dt>
<dd><p>The call was interrupted by the user.
</p></dd>
</dl>

</dd>
</dl>

<p><small>GDB</small> takes over the full task of calling the necessary host calls 
to perform the <code>system</code> call.  The return value of <code>system</code> on 
the host is simplified before it&rsquo;s returned
to the target.  Any termination signal information from the child process 
is discarded, and the return value consists
entirely of the exit status of the called command.
</p>
<p>Due to security concerns, the <code>system</code> call is by default refused
by <small>GDB</small>.  The user has to allow this call explicitly with the
<code>set remote system-call-allowed 1</code> command.
</p>
<dl compact="compact">
<dt><code>set remote system-call-allowed</code></dt>
<dd><a name="index-set-remote-system_002dcall_002dallowed"></a>
<p>Control whether to allow the <code>system</code> calls in the File I/O
protocol for the remote target.  The default is zero (disabled).
</p>
</dd>
<dt><code>show remote system-call-allowed</code></dt>
<dd><a name="index-show-remote-system_002dcall_002dallowed"></a>
<p>Show whether the <code>system</code> calls are allowed in the File I/O
protocol.
</p></dd>
</dl>


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