---
name: "nng_tls_config_ca_file"
section: "3tls"
platform: "linux"
package: "libnng-dev"
version: "1.10.1-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/nng_tls_config_ca_file"
---

# nng\_tls\_config\_ca\_file(3tls)

load certificate authority from file

## NAME

nng\_tls\_config\_ca\_file - load certificate authority from file

## SYNOPSIS

```
#include <nng/nng.h>
#include <nng/supplemental/tls/tls.h>
int nng_tls_config_ca_file(nng_tls_config *cfg, const char *path);
```

## DESCRIPTION

The `nng_tls_config_ca_file()` function configures the certificate authority certificate chain and optional revocation list by loading the certificates (and revocation list if present) from a single named file. The file must at least one X.509 certificate in*PEM* \<https://tools.ietf.org/html/rfc7468\> format, and may contain multiple such certificates, as well as zero or more PEM CRL objects. This information is used to validate certificates that are presented by peers, when using the configuration *cfg*.

**Note**\

Certificates **must** be configured when using the authentication mode `NNG_TLS_AUTH_MODE_REQUIRED`.

**Tip**\

This function may be called multiple times, to add additional chains to a configuration, without affecting those added previously.

## RETURN VALUES

This function returns 0 on success, and non-zero otherwise.

## ERRORS

`NNG_ENOMEM`

Insufficient memory is available.

`NNG_EBUSY`

The configuration *cfg* is already in use, and cannot be modified.

`NNG_EINVAL`

The contents of *path* are invalid or do not contain a valid PEM certificate.

`NNG_ENOENT`

The file *path* does not exist.

`NNG_EPERM`

The file *path* is not readable.

## SEE ALSO

[nng\_strerror(3)](/nng_strerror/3.md), [nng\_tls\_config\_alloc(3tls)](/nng_tls_config_alloc/3tls.md), [nng\_tls\_config\_auth\_mode(3tls)](/nng_tls_config_auth_mode/3tls.md), [nng\_tls\_config\_ca\_chain(3tls)](/nng_tls_config_ca_chain/3tls.md), [nng(7)](/nng/7.md)