SSL_get_verify_result - get result of peer certificate verification

       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).

       Copyright 2000-2023 The OpenSSL Project Authors. All Rights Reserved.

       Licensed  under  the  Apache License 2.0 (the "License").  You may not use this file except in compliance
       with the License.  You can obtain  a  copy  in  the  file  LICENSE  in  the  source  distribution  or  at
       <https://www.openssl.org/source/license.html>.

3.5.0                                              2025-06-04                        SSL_GET_VERIFY_RESULT(3SSL)

SSL_get_verify_result() returns the result of the verification of the X509 certificate presented by the
       peer, if any. sslMUSTNOT be NULL.

       SSL_get_verify_result - get result of peer certificate verification

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().

       Sometimes there can be a sequence of errors leading to the verification failure as reported by
       SSL_get_verify_result().  To get the errors, it is necessary to setup a verify callback via
       SSL_CTX_set_verify(3) or SSL_set_verify(3) and retrieve the errors from the error stack there, because
       once SSL_connect(3) returns, these errors may no longer be available.

       The verification result is part of the established session and is restored when a session is reused.

       The following return values can currently occur:

       X509_V_OK
           The verification succeeded or no peer certificate was presented.

       Any other value
           Documented in openssl-verify(1).

ssl(7), SSL_set_verify_result(3), SSL_get_peer_certificate(3), openssl-verify(1)

        #include <openssl/ssl.h>

        long SSL_get_verify_result(const SSL *ssl);