SSL_get_verify_result() returns the result of the verification of the X509 certificate presented by the peer, if any.
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.
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).
The following return values can currently occur:
The verification succeeded or no peer certificate was presented.
- Any other value
Documented in verify(1).