SSL_get_verify_result() returns the result of the verification of the
X509 certificate presented by the peer, if any.
NOTES
SSL_get_verify_result() can only return one error code while the verification
of a certificate can fail because of many reasons at the same time. Only
the last verification error that occurred during the processing is available
from SSL_get_verify_result().
The verification result is part of the established session and is restored
when a session is reused.
BUGS
If no peer certificate was presented, the returned result code is
X509_V_OK. This is because no verification error occurred, it does however
not indicate success. SSL_get_verify_result() is only useful in connection
with SSL_get_peer_certificate(3).
RETURN VALUES
The following return values can currently occur:
X509_V_OK
The verification succeeded or no peer certificate was presented.
