diff options
author | Matt Caswell <matt@openssl.org> | 2019-06-19 10:31:39 +0100 |
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committer | Matt Caswell <matt@openssl.org> | 2019-06-19 11:54:34 +0100 |
commit | a1998897f66858ec7d2d184e98f2be1e46ae2d78 (patch) | |
tree | ae8748a7d1d479689594003fa1049e6dcce5d5fd /doc | |
parent | 6913f5fe05a38fa72213b5b5d1f41ef10ca908bd (diff) |
Add some internal documentation for some thread related functions
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9186)
Diffstat (limited to 'doc')
-rw-r--r-- | doc/internal/man3/ossl_init_thread_deregister.pod | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/doc/internal/man3/ossl_init_thread_deregister.pod b/doc/internal/man3/ossl_init_thread_deregister.pod new file mode 100644 index 0000000000..4481d0c2e2 --- /dev/null +++ b/doc/internal/man3/ossl_init_thread_deregister.pod @@ -0,0 +1,64 @@ +=pod + +=head1 NAME +OSSL_thread_stop_handler_fn, +ossl_init_thread_start, +ossl_init_thread_deregister +- internal thread routines +=head1 SYNOPSIS + + #include "internal/cryptlib_int.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 registerd using the function ossl_init_thread_start(). +The B<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 B<arg> parameter is passed +back as an argument to the stop handler when it is later invoked. Finally the +B<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 B<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 |