| =pod |
| |
| =head1 NAME |
| |
| OSSL_thread_stop_handler_fn, |
| ossl_init_thread_start, |
| ossl_init_thread_deregister |
| - internal thread routines |
| |
| =head1 SYNOPSIS |
| |
| #include "crypto/cryptlib.h" |
| #include <openssl/core.h> |
| |
| typedef void (*OSSL_thread_stop_handler_fn)(void *arg); |
| |
| int ossl_init_thread_start(const void *index, void *arg, |
| OSSL_thread_stop_handler_fn handfn); |
| int ossl_init_thread_deregister(void *index); |
| |
| =head1 DESCRIPTION |
| |
| Thread aware code may be informed about when a thread is stopping, typically to |
| perform some cleanup operation. |
| Thread stop events may be detected by OpenSSL either automatically (using the |
| capabilities of the underlying threading library) where possible or explicitly |
| by the application calling OPENSSL_thread_stop() or OPENSSL_thread_stop_ex(). |
| |
| Thread aware code registers a "stop handler" for each new thread that it uses. |
| Typically, when a new thread is being used, code will add a new value to some |
| thread local variable and then register a stop handler. When the thread is |
| stopping the stop handler is called (while on that thread) and the code can |
| clean up the value stored in the thread local variable. |
| |
| A new stop handler is registered using the function ossl_init_thread_start(). |
| The I<index> parameter should be a unique value that can be used to identify a |
| set of common stop handlers and is passed in a later call to |
| ossl_init_thread_deregister. If no later call to ossl_init_thread_deregister is |
| made then NULL can be passed for this parameter. The I<arg> parameter is passed |
| back as an argument to the stop handler when it is later invoked. Finally the |
| I<handfn> is a function pointer to the stop handler itself. |
| |
| In the event that previously registered stop handlers need to be deregistered |
| then this can be done using the function ossl_init_thread_deregister(). |
| This will deregister all stop handlers (no matter which thread they were |
| registered for) which the same I<index> value. |
| |
| =head1 RETURN VALUES |
| |
| ossl_init_thread_start() and ossl_init_thread_deregister() return 1 for success |
| or 0 on error. |
| |
| =head1 HISTORY |
| |
| The functions described here were all added in OpenSSL 3.0. |
| |
| =head1 COPYRIGHT |
| |
| Copyright 2019 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 |
| L<https://www.openssl.org/source/license.html>. |
| |
| =cut |