- NAME
- SYNOPSIS
- DESCRIPTION
- RETURN VALUES
- NOTES
- SEE ALSO
- HISTORY
- COPYRIGHT

# NAME

X509_add_cert, X509_add_certs - X509 certificate list addition functions

# SYNOPSIS

    #include <openssl/x509.h>

    int X509_add_cert(STACK_OF(X509) *sk, X509 *cert, int flags);
    int X509_add_certs(STACK_OF(X509) *sk, STACK_OF(X509) *certs, int flags);

# DESCRIPTION

X509_add_cert() adds a certificate cert to the given list sk. It is an error for the cert argument to be NULL.

X509_add_certs() adds a list of certificate certs to the given list sk. The certs argument may be NULL, which implies no effect. It does not modify the list certs but in case the X509_ADD_FLAG_UP_REF flag (described below) is set the reference counters of those of its members added to sk are increased.

Both these functions have a flags parameter, which is used to control details of the operation.

The value X509_ADD_FLAG_DEFAULT, which equals 0, means no special semantics.

If X509_ADD_FLAG_UP_REF is set then the reference counts of those certificates added successfully are increased.

If X509_ADD_FLAG_PREPEND is set then the certificates are prepended to sk. By default they are appended to sk. In both cases the original order of the added certificates is preserved.

If X509_ADD_FLAG_NO_DUP is set then certificates already contained in sk, which is determined using X509_cmp(3), are ignored.

If X509_ADD_FLAG_NO_SS is set then certificates that are marked self-signed, which is determined using X509_self_signed(3), are ignored.

# RETURN VALUES

Both functions return 1 for success and 0 for failure.

# NOTES

If X509_add_certs() is used with the flags X509_ADD_FLAG_NO_DUP or X509_ADD_FLAG_NO_SS it is advisable to use also X509_ADD_FLAG_UP_REF because otherwise likely not for all members of the certs list the ownership is transferred to the list of certificates sk.

Care should also be taken in case the certs argument equals sk.

# SEE ALSO

X509_cmp(3) X509_self_signed(3)

# HISTORY

The functions X509_add_cert() and X509_add_certs() were added in OpenSSL 3.0.

# COPYRIGHT

Copyright 2019-2025 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.