1=pod
2
3=head1 NAME
4
5OPENSSL_init_ssl - OpenSSL (libssl and libcrypto) initialisation
6
7=head1 SYNOPSIS
8
9 #include <openssl/ssl.h>
10
11 int OPENSSL_init_ssl(uint64_t opts, const OPENSSL_INIT_SETTINGS *settings);
12
13=head1 DESCRIPTION
14
15During normal operation OpenSSL (libssl and libcrypto) will allocate various
16resources at start up that must, subsequently, be freed on close down of the
17library. Additionally some resources are allocated on a per thread basis (if the
18application is multi-threaded), and these resources must be freed prior to the
19thread closing.
20
21As of version 1.1.0 OpenSSL will automatically allocate all resources that it
22needs so no explicit initialisation is required. Similarly it will also
23automatically deinitialise as required.
24
25However, there may be situations when explicit initialisation is desirable or
26needed, for example when some nondefault initialisation is required. The
27function OPENSSL_init_ssl() can be used for this purpose. Calling
28this function will explicitly initialise BOTH libcrypto and libssl. To
29explicitly initialise ONLY libcrypto see the
30L<OPENSSL_init_crypto(3)> function.
31
32Numerous internal OpenSSL functions call OPENSSL_init_ssl().
33Therefore, in order to perform nondefault initialisation,
34OPENSSL_init_ssl() MUST be called by application code prior to
35any other OpenSSL function calls.
36
37The B<opts> parameter specifies which aspects of libssl and libcrypto should be
38initialised. Valid options for libcrypto are described on the
39L<OPENSSL_init_crypto(3)> page. In addition to any libcrypto
40specific option the following libssl options can also be used:
41
42=over 4
43
44=item OPENSSL_INIT_NO_LOAD_SSL_STRINGS
45
46Suppress automatic loading of the libssl error strings. This option is
47not a default option. Once selected subsequent calls to
48OPENSSL_init_ssl() with the option
49B<OPENSSL_INIT_LOAD_SSL_STRINGS> will be ignored.
50
51=item OPENSSL_INIT_LOAD_SSL_STRINGS
52
53Automatic loading of the libssl error strings. This option is a
54default option. Once selected subsequent calls to
55OPENSSL_init_ssl() with the option
56B<OPENSSL_INIT_LOAD_SSL_STRINGS> will be ignored.
57
58=back
59
60OPENSSL_init_ssl() takes a B<settings> parameter which can be used to
61set parameter values.  See L<OPENSSL_init_crypto(3)> for details.
62
63=head1 RETURN VALUES
64
65The function OPENSSL_init_ssl() returns 1 on success or 0 on error.
66
67=head1 SEE ALSO
68
69L<OPENSSL_init_crypto(3)>
70
71=head1 HISTORY
72
73The OPENSSL_init_ssl() function was added in OpenSSL 1.1.0.
74
75=head1 COPYRIGHT
76
77Copyright 2016-2020 The OpenSSL Project Authors. All Rights Reserved.
78
79Licensed under the Apache License 2.0 (the "License").  You may not use
80this file except in compliance with the License.  You can obtain a copy
81in the file LICENSE in the source distribution or at
82L<https://www.openssl.org/source/license.html>.
83
84=cut
85