SSL_get_extms_support - extended master secret support

       Copyright 2015-2016 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_EXTMS_SUPPORT(3SSL)

SSL_get_extms_support() indicates whether the current session used extended master secret.

       This function is implemented as a macro.

       SSL_get_extms_support - extended master secret support

SSL_get_extms_support() returns 1 if the current session used extended master secret, 0 if it did not and
       -1 if a handshake is currently in progress i.e. it is not possible to determine if extended master secret
       was used.

ssl(7)

        #include <openssl/ssl.h>

        int SSL_get_extms_support(SSL *ssl);