X509_get_version, X509_set_version, X509_REQ_get_version, X509_REQ_set_version, X509_ACERT_get_version,

       Copyright 2015-2024 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                             X509_GET_VERSION(3SSL)

X509_get_version() returns the numerical value of the version field of certificate x. These correspond to
       the constants X509_VERSION_1, X509_VERSION_2, and X509_VERSION_3. Note: the values of these constants are
       defined by standards (X.509 et al) to be one less than the certificate version. So X509_VERSION_3 has
       value 2 and X509_VERSION_1 has value 0.

       X509_set_version() sets the numerical value of the version field of certificate x to version.

       Similarly X509_REQ_get_version(), X509_REQ_set_version(), X509_ACERT_get_version(),
       X509_ACERT_set_version(), X509_CRL_get_version() and X509_CRL_set_version() get and set the version
       number of certificate requests and CRLs. They use constants X509_REQ_VERSION_1, X509_ACERT_VERSION_2,
       X509_CRL_VERSION_1, and X509_CRL_VERSION_2.

X509_get_version(), X509_REQ_get_version() and X509_CRL_get_version() are functions in OpenSSL 1.1.0, in
       previous versions they were macros.

       X509_ACERT_get_version(), X509_ACERT_set_version() were added in OpenSSL 3.4.

       X509_get_version, X509_set_version, X509_REQ_get_version, X509_REQ_set_version, X509_ACERT_get_version,
       X509_ACERT_set_version, X509_CRL_get_version, X509_CRL_set_version - get or set certificate, certificate
       request or CRL version

       The version field of certificates, certificate requests and CRLs has a DEFAULT value of v1(0) meaning the
       field should be omitted for version 1. This is handled transparently by these functions.

X509_get_version(), X509_REQ_get_version() and X509_CRL_get_version() return the numerical value of the
       version field.

       X509_set_version(), X509_REQ_set_version() and X509_CRL_set_version() return 1 for success and 0 for
       failure.

d2i_X509(3), ERR_get_error(3), X509_CRL_get0_by_serial(3), X509_get0_signature(3), X509_get_ext_d2i(3),
       X509_get_extension_flags(3), X509_get_pubkey(3), X509_get_subject_name(3), X509_NAME_add_entry_by_txt(3),
       X509_NAME_ENTRY_get_object(3), X509_NAME_get_index_by_NID(3), X509_NAME_print_ex(3), X509_new(3),
       X509_sign(3), X509V3_get_d2i(3), X509_verify_cert(3)

        #include <openssl/x509.h>

        long X509_get_version(const X509 *x);
        int X509_set_version(X509 *x, long version);

        long X509_REQ_get_version(const X509_REQ *req);
        int X509_REQ_set_version(X509_REQ *x, long version);

        long X509_CRL_get_version(const X509_CRL *crl);
        int X509_CRL_set_version(X509_CRL *x, long version);

        #include <openssl/x509_acert.h>

        int X509_ACERT_set_version(X509_ACERT *x, long version);
        long X509_ACERT_get_version(const X509_ACERT *x);