=pod =head1 NAME X509_check_ca - check if given certificate is CA certificate =head1 SYNOPSIS #include int X509_check_ca(X509 *cert); =head1 DESCRIPTION This function checks if given certificate is CA certificate (can be used to sign other certificates). =head1 RETURN VALUES Function return 0, if it is not CA certificate, 1 if it is proper X509v3 CA certificate with B extension CA:TRUE, 3, if it is self-signed X509 v1 certificate, 4, if it is certificate with B extension with bit B set, but without B, and 5 if it has outdated Netscape Certificate Type extension telling that it is CA certificate.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 used to sign other certificates. =head1 SEE ALSO L, L, L =head1 COPYRIGHT Copyright 2015-2018 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 L. =cut