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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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