---
name: "libressl-OPENSSL_config"
section: "3"
platform: "linux"
package: "libressl"
version: "4.4.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/libressl-OPENSSL_config"
---

# libressl-OPENSSL\_config(3)

simple crypto and ssl library configuration

## NAME

**OPENSSL\_config**, **OPENSSL\_no\_config** – simple crypto and ssl library configuration

## SYNOPSIS

Crypto Library (libcrypto, -lcrypto)

**#include \<openssl/conf.h\>**

*void*\

**OPENSSL\_config**(*const char \*appname*);

*void*\

**OPENSSL\_no\_config**(*void*);

## DESCRIPTION

**OPENSSL\_config**() initializes the crypto library and calls CONF\_modules\_load\_file(3) with the standard configuration file and the given *appname*. If *appname* is NULL, then the default name **openssl\_conf** is used. Any errors are ignored. Further calls to **OPENSSL\_config**() have no effect.

**OPENSSL\_no\_config**() suppresses the loading of the standard configuration file, so that any future calls to **OPENSSL\_config**() or to OPENSSL\_init\_crypto(3) will ensure the library is initialized but no configuration file will be loaded.

Calling these functions is optional. All required initialization of the crypto libraries happens automatically when needed.

To use a non-standard configuration file, refer to CONF\_modules\_load\_file(3).

Internally, **OPENSSL\_config**() calls OPENSSL\_init\_crypto(3).

If an application is compiled with the preprocessor symbol OPENSSL\_LOAD\_CONF defined, OpenSSL\_add\_all\_algorithms(3) automatically calls **OPENSSL\_config**().

Applications should free up configuration at application closedown by calling CONF\_modules\_free(3).

## FILES

- */etc/ssl/openssl.cnf*

  standard configuration file

## SEE ALSO

CONF\_modules\_free(3), CONF\_modules\_load\_file(3), [crypto(3)](/crypto/3.md), OPENSSL\_VERSION\_NUMBER(3), [openssl.cnf(5)](/openssl.cnf/5.md), [x509v3.cnf(5)](/x509v3.cnf/5.md)

## HISTORY

**OPENSSL\_config**() and **OPENSSL\_no\_config**() first appeared in OpenSSL 0.9.7 and have been available since OpenBSD 3.2.