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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>‘<samp>Fsystem,<var>commandptr</var>/<var>len</var></samp>’
</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’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’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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