SSL_SESSION_is_resumable - determine whether an SSL_SESSION object can be used for resumption

       Copyright 2017-2018 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_SESSION_IS_RESUMABLE(3SSL)

SSL_SESSION_is_resumable() determines whether an SSL_SESSION object can be used to resume a session or
       not. Returns 1 if it can or 0 if not. Note that attempting to resume with a non-resumable session will
       result in a full handshake.

       The SSL_SESSION_is_resumable() function was added in OpenSSL 1.1.1.

       SSL_SESSION_is_resumable - determine whether an SSL_SESSION object can be used for resumption

SSL_SESSION_is_resumable() returns 1 if the session is resumable or 0 otherwise.

ssl(7), SSL_get_session(3), SSL_CTX_sess_set_new_cb(3)

        #include <openssl/ssl.h>

        int SSL_SESSION_is_resumable(const SSL_SESSION *s);