. We can use the <a href="../man3/SSL_get_verify_result.html">SSL_get_verify_result(3)</a> function to find out more information about the verification failure. A return value of <b>X509_V_OK</b> indicates that the verification was successful (so the connection error must be due to some other cause). Otherwise we use the <a href="../man3/X509_verify_cert_error_string.html">X509_verify_cert_error_string(3)</a> function to get a human readable error message.</p>

<h2 id="Sending-and-receiving-data">Sending an