OPENSSL_init_ssl - OpenSSL (libssl and libcrypto) initialisation
#include <openssl/ssl.h>
int OPENSSL_init_ssl(uint64_t opts, const OPENSSL_INIT_SETTINGS *settings);
During normal operation OpenSSL (libssl and libcrypto) will allocate various
resources at start up that must, subsequently, be freed on close down of the
library. Additionally some resources are allocated on a per thread basis (if
the application is multi-threaded), and these resources must be freed prior to
the thread closing.
As of version 1.1.0 OpenSSL will automatically allocate all resources that it
needs so no explicit initialisation is required. Similarly it will also
automatically deinitialise as required.
However, there may be situations when explicit initialisation is desirable or
needed, for example when some nondefault initialisation is required. The
function
OPENSSL_init_ssl() can be used for this purpose. Calling this
function will explicitly initialise BOTH libcrypto and libssl. To explicitly
initialise ONLY libcrypto see the
OPENSSL_init_crypto(3) function.
Numerous internal OpenSSL functions call
OPENSSL_init_ssl(). Therefore,
in order to perform nondefault initialisation,
OPENSSL_init_ssl() MUST
be called by application code prior to any other OpenSSL function calls.
The
opts parameter specifies which aspects of libssl and libcrypto should
be initialised. Valid options for libcrypto are described on the
OPENSSL_init_crypto(3) page. In addition to any libcrypto specific
option the following libssl options can also be used:
- OPENSSL_INIT_NO_LOAD_SSL_STRINGS
- Suppress automatic loading of the libssl error strings.
This option is not a default option. Once selected subsequent calls to
OPENSSL_init_ssl() with the option
OPENSSL_INIT_LOAD_SSL_STRINGS will be ignored.
- OPENSSL_INIT_LOAD_SSL_STRINGS
- Automatic loading of the libssl error strings. This option
is a default option. Once selected subsequent calls to
OPENSSL_init_ssl() with the option
OPENSSL_INIT_LOAD_SSL_STRINGS will be ignored.
OPENSSL_init_ssl() takes a
settings parameter which can be used to
set parameter values. See
OPENSSL_init_crypto(3) for details.
The function
OPENSSL_init_ssl() returns 1 on success or 0 on error.
OPENSSL_init_crypto(3)
The
OPENSSL_init_ssl() function was added in OpenSSL 1.1.0.
Copyright 2016-2020 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>.