B<basicConstraints>, and 5 if it has outdated Netscape Certificate Type
extension telling that it is CA certificate.
-Actually, any non-zero value means that this certificate could have been
+This function will also return 0 on error.
+
+Actually, any nonzero value means that this certificate could have been
used to sign other certificates.
=head1 SEE ALSO
=head1 COPYRIGHT
-Copyright 2015-2017 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved.
-Licensed under the OpenSSL license (the "License"). You may not use
+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
L<https://www.openssl.org/source/license.html>.