OPENSSL_init_ssl - OpenSSL (libssl and libcrypto) initialisation

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       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>.

3.5.0                                              2025-06-04                             OPENSSL_INIT_SSL(3SSL)

       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 OPENSSL_init_ssl() function was added in OpenSSL 1.1.0.

       OPENSSL_init_ssl - OpenSSL (libssl and libcrypto) initialisation

       The function OPENSSL_init_ssl() returns 1 on success or 0 on error.

OPENSSL_init_crypto(3)

        #include <openssl/ssl.h>

        int OPENSSL_init_ssl(uint64_t opts, const OPENSSL_INIT_SETTINGS *settings);