SSL_CTX_add_extra_chain_cert, SSL_CTX_get_extra_chain_certs, SSL_CTX_get_extra_chain_certs_only,

       Copyright 2000-2018 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_CTX_ADD_EXTRA_CHAIN_CERT(3SSL)

SSL_CTX_add_extra_chain_cert() adds the certificate x509 to the extra chain certificates associated with
       ctx. Several certificates can be added one after another.

       SSL_CTX_get_extra_chain_certs() retrieves the extra chain certificates associated with ctx, or the chain
       associated with the current certificate of ctx if the extra chain is empty.  The returned stack should
       not be freed by the caller.

       SSL_CTX_get_extra_chain_certs_only() retrieves the extra chain certificates associated with ctx.  The
       returned stack should not be freed by the caller.

       SSL_CTX_clear_extra_chain_certs() clears all extra chain certificates associated with ctx.

       These functions are implemented as macros.

       SSL_CTX_add_extra_chain_cert, SSL_CTX_get_extra_chain_certs, SSL_CTX_get_extra_chain_certs_only,
       SSL_CTX_clear_extra_chain_certs - add, get or clear extra chain certificates

       When sending a certificate chain, extra chain certificates are sent in order following the end entity
       certificate.

       If no chain is specified, the library will try to complete the chain from the available CA certificates
       in the trusted CA storage, see SSL_CTX_load_verify_locations(3).

       The x509 certificate provided to SSL_CTX_add_extra_chain_cert() will be freed by the library when the
       SSL_CTX is destroyed. An application shouldnot free the x509 object.

       Only one set of extra chain certificates can be specified per SSL_CTX structure. Different chains for
       different certificates (for example if both RSA and DSA certificates are specified by the same server) or
       different SSL structures with the same parent SSL_CTX cannot be specified using this function. For more
       flexibility functions such as SSL_add1_chain_cert() should be used instead.

SSL_CTX_add_extra_chain_cert() and SSL_CTX_clear_extra_chain_certs() return 1 on success and 0 for
       failure. Check out the error stack to find out the reason for failure.

ssl(7), SSL_CTX_use_certificate(3), SSL_CTX_set_client_cert_cb(3), SSL_CTX_load_verify_locations(3)
       SSL_CTX_set0_chain(3) SSL_CTX_set1_chain(3) SSL_CTX_add0_chain_cert(3) SSL_CTX_add1_chain_cert(3)
       SSL_set0_chain(3) SSL_set1_chain(3) SSL_add0_chain_cert(3) SSL_add1_chain_cert(3)
       SSL_CTX_build_cert_chain(3) SSL_build_cert_chain(3)

        #include <openssl/ssl.h>

        long SSL_CTX_add_extra_chain_cert(SSL_CTX *ctx, X509 *x509);
        long SSL_CTX_get_extra_chain_certs(SSL_CTX *ctx, STACK_OF(X509) **sk);
        long SSL_CTX_get_extra_chain_certs_only(SSL_CTX *ctx, STACK_OF(X509) **sk);
        long SSL_CTX_clear_extra_chain_certs(SSL_CTX *ctx);