n. If the extension does not exist, returns an error.</p>

<p><b>X509V3_ADD_KEEP_EXISTING</b> appends a new extension only if the extension does not exist. An error is <b>not</b> returned if the extension exists.</p>

<p><b>X509V3_ADD_DELETE</b> deletes and frees an existing extension. If the extension does not exist, returns an error. No new extension is added.</p>

<p>If <b>X509V3_ADD_SILENT</b> is bitwise ORed with <i>flags</i>: any error returned will not be added to the error queue.</p>

<p>The functio