1=pod 2 3=head1 NAME 4 5X509_add_cert, 6X509_add_certs - 7X509 certificate list addition functions 8 9=head1 SYNOPSIS 10 11 #include <openssl/x509.h> 12 13 int X509_add_cert(STACK_OF(X509) *sk, X509 *cert, int flags); 14 int X509_add_certs(STACK_OF(X509) *sk, STACK_OF(X509) *certs, int flags); 15 16=head1 DESCRIPTION 17 18X509_add_cert() adds a certificate I<cert> to the given list I<sk>. 19It is an error for the I<cert> argument to be NULL. 20 21X509_add_certs() adds a list of certificate I<certs> to the given list I<sk>. 22The I<certs> argument may be NULL, which implies no effect. 23It does not modify the list I<certs> but 24in case the B<X509_ADD_FLAG_UP_REF> flag (described below) is set 25the reference counters of those of its members added to I<sk> are increased. 26 27Both these functions have a I<flags> parameter, 28which is used to control details of the operation. 29 30The value B<X509_ADD_FLAG_DEFAULT>, which equals 0, means no special semantics. 31 32If B<X509_ADD_FLAG_UP_REF> is set then 33the reference counts of those certificates added successfully are increased. 34 35If B<X509_ADD_FLAG_PREPEND> is set then the certificates are prepended to I<sk>. 36By default they are appended to I<sk>. 37In both cases the original order of the added certificates is preserved. 38 39If B<X509_ADD_FLAG_NO_DUP> is set then certificates already contained in I<sk>, 40which is determined using L<X509_cmp(3)>, are ignored. 41 42If B<X509_ADD_FLAG_NO_SS> is set then certificates that are marked self-signed, 43which is determined using L<X509_self_signed(3)>, are ignored. 44 45=head1 RETURN VALUES 46 47Both functions return 1 for success and 0 for failure. 48 49=head1 NOTES 50 51If X509_add_certs() is used with the flags B<X509_ADD_FLAG_NO_DUP> or 52B<X509_ADD_FLAG_NO_SS> it is advisable to use also B<X509_ADD_FLAG_UP_REF> 53because otherwise likely not for all members of the I<certs> list 54the ownership is transferred to the list of certificates I<sk>. 55 56Care should also be taken in case the I<certs> argument equals I<sk>. 57 58=head1 SEE ALSO 59 60L<X509_cmp(3)> 61L<X509_self_signed(3)> 62 63=head1 HISTORY 64 65The functions X509_add_cert() and X509_add_certs() 66were added in OpenSSL 3.0. 67 68=head1 COPYRIGHT 69 70Copyright 2019-2025 The OpenSSL Project Authors. All Rights Reserved. 71 72Licensed under the Apache License 2.0 (the "License"). You may not use 73this file except in compliance with the License. You can obtain a copy 74in the file LICENSE in the source distribution or at 75L<https://www.openssl.org/source/license.html>. 76 77=cut 78