<html> <head><title>dkim_get_sigsubstring()</title></head> <body> <!-- $Id: dkim_get_sigsubstring.html,v 1.3 2010/07/24 04:52:15 cm-msk Exp $ --> <h1>dkim_get_sigsubstring()</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> <a href="dkim_stat.html"><tt>DKIM_STAT</tt></a> dkim_get_sigsubstring( <a href="dkim.html"><tt>DKIM</tt></a> *dkim, <a href="dkim_siginfo.html"><tt>DKIM_SIGINFO</tt></a> *sig, char *buf, size_t *buflen ); </pre> Retrieve a minimal substring of the actual signature (i.e. the "b=" tag value) from a specified signature, of sufficient length to identify this signature uniquely from others. </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_getsig()</tt> is called after <a href="dkim_eom.html"><tt>dkim_eom()</tt></a> when <tt>dkim</tt> is a verifying handle, i.e. one returned by an earlier call to <a href="dkim_verify.html"><tt>dkim_verify()</tt></a>. </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>dkim</td> <td>Message-specific handle, returned by <a href="dkim_sign.html"> <tt>dkim_sign()</tt></a>. </td></tr> <tr valign="top"><td>sig</td> <td>Signature-specific handle, retrieved by a prior call to <a href="dkim_getsiglist.html"><tt>dkim_getsiglist()</tt></a>. </td></tr> <tr valign="top"><td>buf</td> <td>Pointer to a buffer that should receive a minimal unique substring of the digital signature portion of <tt>sig</tt>. </td></tr> <tr valign="top"><td>buflen</td> <td>The address of an integer that should contain the number of bytes available at <tt>buf</tt> and will be updated to contain the number of bytes needed to produce a minimal substring. </td></tr> </table> </td></tr> <!----------- Notes ----------> <tr> <th valign="top" align=left>NOTES</th> <td> <ul> <li>No fewer than eight bytes will be requested. If two or more signatures have the same initial byte sequences in "b=" tags, larger lengths will be required, theoretically requiring as much as the entire signature. <li>If the size of <tt>buf</tt> is too small to contain the minimal substring of <tt>sig</tt>, <tt>DKIM_STAT_NORESOURCE</tt> is returned, <tt>buflen</tt> will be updated to indicate the minimal number of bytes required, and <tt>buf</tt> will be unchanged. <li>The string written to <tt>buf</tt> will be NULL-terminated unless the provided buffer is exactly the right size to contain the output. </ul> </td> </tr> </table> <hr size="1"> <font size="-1"> Copyright (c) 2005, 2007 Sendmail, Inc. and its suppliers. All rights reserved. <br> Copyright (c) 2010, 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>