---
name: "SSL_load_client_CA_file"
section: "3ssl"
platform: "linux"
package: "openssl"
version: "3.6.5-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/SSL_load_client_CA_file"
---

# SSL\_load\_client\_CA\_file(3ssl)

load certificate names

## NAME

SSL\_load\_client\_CA\_file\_ex, SSL\_load\_client\_CA\_file, SSL\_add\_file\_cert\_subjects\_to\_stack, SSL\_add\_dir\_cert\_subjects\_to\_stack, SSL\_add\_store\_cert\_subjects\_to\_stack - load certificate names

## SYNOPSIS

```
 #include <openssl/ssl.h>
 STACK_OF(X509_NAME) *SSL_load_client_CA_file_ex(const char *file,
                                                 OSSL_LIB_CTX *libctx,
                                                 const char *propq);
 STACK_OF(X509_NAME) *SSL_load_client_CA_file(const char *file);
 int SSL_add_file_cert_subjects_to_stack(STACK_OF(X509_NAME) *stack,
                                         const char *file);
 int SSL_add_dir_cert_subjects_to_stack(STACK_OF(X509_NAME) *stack,
                                        const char *dir);
 int SSL_add_store_cert_subjects_to_stack(STACK_OF(X509_NAME) *stack,
                                          const char *store);
```

## DESCRIPTION

**SSL\_load\_client\_CA\_file\_ex()** reads certificates from *file* and returns a STACK\_OF(X509\_NAME) with the subject names found. The library context *libctx* and property query *propq* are used when fetching algorithms from providers.

**SSL\_load\_client\_CA\_file()** is similar to **SSL\_load\_client\_CA\_file\_ex()** but uses NULL for the library context *libctx* and property query *propq*.

**SSL\_add\_file\_cert\_subjects\_to\_stack()** reads certificates from *file*, and adds their subject name to the already existing *stack*.

**SSL\_add\_dir\_cert\_subjects\_to\_stack()** reads certificates from every file in the directory *dir*, and adds their subject name to the already existing *stack*.

**SSL\_add\_store\_cert\_subjects\_to\_stack()** loads certificates from the *store* URI, and adds their subject name to the already existing *stack*.

## NOTES

**SSL\_load\_client\_CA\_file()** reads a file of PEM formatted certificates and extracts the X509\_NAMES of the certificates found. While the name suggests the specific usage as support function for **SSL\_CTX\_set\_client\_CA\_list**(3), it is not limited to CA certificates.

## RETURN VALUES

The following return values can occur for **SSL\_load\_client\_CA\_file\_ex()**, and **SSL\_load\_client\_CA\_file()**:

- NULL

  The operation failed, check out the error stack for the reason.

- Pointer to STACK\_OF(X509\_NAME)

  Pointer to the subject names of the successfully read certificates.

The following return values can occur for **SSL\_add\_file\_cert\_subjects\_to\_stack()**, **SSL\_add\_dir\_cert\_subjects\_to\_stack()**, and **SSL\_add\_store\_cert\_subjects\_to\_stack()**:

- 0 (Failure)

  The operation failed.

- 1 (Success)

  The operation succeeded.

## EXAMPLES

Load names of CAs from file and use it as a client CA list:

```
 SSL_CTX *ctx;
 STACK_OF(X509_NAME) *cert_names;
 ...
 cert_names = SSL_load_client_CA_file("/path/to/CAfile.pem");
 if (cert_names != NULL)
     SSL_CTX_set_client_CA_list(ctx, cert_names);
 else
     /* error */
 ...
```

## SEE ALSO

[**ssl**(7)](/ssl/7.md), **ossl\_store**(7), **SSL\_CTX\_set\_client\_CA\_list**(3)

## HISTORY

**SSL\_load\_client\_CA\_file\_ex()** and **SSL\_add\_store\_cert\_subjects\_to\_stack()** were added in OpenSSL 3.0.

## COPYRIGHT

Copyright 2000-2024 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\>.