openssl/doc/man3/OPENSSL_fork_prepare.pod

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=head1 NAME

OPENSSL_fork_prepare,
OPENSSL_fork_parent,
OPENSSL_fork_child
- OpenSSL fork handlers

=head1 SYNOPSIS

 #include <openssl/crypto.h>

The following functions have been deprecated since OpenSSL 3.0, and can be
hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value,
see L<openssl_user_macros(7)>:

 void OPENSSL_fork_prepare(void);
 void OPENSSL_fork_parent(void);
 void OPENSSL_fork_child(void);

=head1 DESCRIPTION

These methods are currently unused, and as such, no replacement methods are
required or planned.

OpenSSL has state that should be reset when a process forks. For example,
the entropy pool used to generate random numbers (and therefore encryption
keys) should not be shared across multiple programs.
The OPENSSL_fork_prepare(), OPENSSL_fork_parent(), and OPENSSL_fork_child()
functions are used to reset this internal state.

Platforms without fork(2) will probably not need to use these functions.
Platforms with fork(2) but without pthread_atfork(3) will probably need
to call them manually, as described in the following paragraph.  Platforms
such as Linux that have both functions will normally not need to call these
functions as the OpenSSL library will do so automatically.

L<OPENSSL_init_crypto(3)> will register these functions with the appropriate
handler, when the B<OPENSSL_INIT_ATFORK> flag is used. For other
applications, these functions can be called directly. They should be used
according to the calling sequence described by the pthread_atfork(3)
documentation, which is summarized here.  OPENSSL_fork_prepare() should
be called before a fork() is done.  After the fork() returns, the parent
process should call OPENSSL_fork_parent() and the child process should
call OPENSSL_fork_child().

=head1 RETURN VALUES

OPENSSL_fork_prepare(), OPENSSL_fork_parent() and OPENSSL_fork_child() do not
return values.

=head1 SEE ALSO

L<OPENSSL_init_crypto(3)>

=head1 HISTORY

These functions were added in OpenSSL 1.1.1.

=head1 COPYRIGHT

Copyright 2017-2020 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
L<https://www.openssl.org/source/license.html>.

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