=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 VALUE 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X509 v1 certificate, 4, if it is certificate with B extension with bit B set, but without B, and 5 if it has outdated Netscape Certificate Type extension telling that it is CA certificate.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 2015-2016 The OpenSSL Project Authors. All Rights Reserved. Licensed under the OpenSSL license (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