<html> <head><title>dkim_dns_set_query_cancel()</title></head> <body> <!-- $Id: dkim_dns_set_query_cancel.html,v 1.2 2010/07/24 04:52:15 cm-msk Exp $ --> <h1>dkim_dns_set_query_cancel()</h1> <p align="right"><a href="index.html">[back to index]</a></p> <table border="0" cellspacing=4 cellpadding=4> <!---------- Synopsis -----------> <tr><th valign="top" align=left width=150>SYNOPSIS</th><td> <pre> #include <dkim.h> <tt>void</tt> dkim_dns_set_query_cancel( <a href="dkim_lib.html"><tt>DKIM_LIB</tt></a> *libopendkim, <tt>int</tt> (*func)(<tt>void *, void *</tt>) ); </pre> Declares the function to be used by a libopendkim instance when it needs to cancel a DNS query already in progress. By default, a stub function that does nothing is set, since there is no way to cancel a query in the standard UNIX resolver library. <p> The function will be passed the following arguments: <ol> <li> An opaque DNS service handle as previously specified by a call to <a href="dkim_dns_set_query_service.html"><tt>dkim_dns_set_query_service()</tt></a> <li> A handle for a previously initiated DNS query as returned by the function provided by <a href="dkim_dns_set_query_start.html"><tt>dkim_dns_set_query_start()</tt></a> </ol> The function is expected to return one of the following: <ul> <li><tt>DKIM_DNS_SUCCESS</tt> -- query was successfully canceled <li><tt>DKIM_DNS_ERROR</tt> -- an error occurred </ul> </td></tr> <!----------- Description ----------> <tr><th valign="top" align=left>DESCRIPTION</th><td> <table border="1" cellspacing=1 cellpadding=4> <tr align="left" valign=top> <th width="80">Called When</th> <td><tt>dkim_dns_set_query_cancel()</tt> can be called at any time, but is presumably most useful prior to doing any DNS operations such as are done during <a href="dkim_eoh.html"><tt>dkim_eoh()</tt></a> when verifying. </td> </tr> </table> <!----------- Arguments ----------> <tr><th valign="top" align=left>ARGUMENTS</th><td> <table border="1" cellspacing=0> <tr bgcolor="#dddddd"><th>Argument</th><th>Description</th></tr> <tr valign="top"><td>libopendkim</td> <td>The library instantiation handle, returned by <a href="dkim_init.html"><tt>dkim_init()</tt></a>. </td></tr> <tr valign="top"><td>func</td> <td>A pointer to a function that should be used to cancel DNS queries. </td></tr> </table> </td></tr> <!----------- Return Values ----------> <tr> <th valign="top" align=left>RETURN VALUES</th> <td> <ul> <li>None. </ul> </td> </tr> <!----------- Notes ----------> <tr> <th valign="top" align=left>NOTES</th> <td> <ul> <li>None. </ul> </td> </tr> </table> <hr size="1"> <font size="-1"> Copyright (c) 2007 Sendmail, Inc. and its suppliers. All rights reserved. <br> Copyright (c) 2011, The OpenDKIM Project. All rights reserved. <br> By using this file, you agree to the terms and conditions set forth in the respective licenses. </font> </body> </html>