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SSL_GET_ALL_ASYNC_FDS(3)            OpenSSL           SSL_GET_ALL_ASYNC_FDS(3)
NAME
       SSL_waiting_for_async, SSL_get_all_async_fds, SSL_get_changed_async_fds
       - manage asynchronous operations
SYNOPSIS
        #include <openssl/async.h>
        #include <openssl/ssl.h>
        int SSL_waiting_for_async(SSL *s);
        int SSL_get_all_async_fds(SSL *s, OSSL_ASYNC_FD *fd, size_t *numfds);
        int SSL_get_changed_async_fds(SSL *s, OSSL_ASYNC_FD *addfd, size_t *numaddfds,
                                      OSSL_ASYNC_FD *delfd, size_t *numdelfds);
DESCRIPTION
       SSL_waiting_for_async() determines whether an SSL connection is
       currently waiting for asynchronous operations to complete (see the
       SSL_MODE_ASYNC mode in SSL_CTX_set_mode(3)).
       SSL_get_all_async_fds() returns a list of file descriptor which can be
       used in a call to select() or poll() to determine whether the current
       asynchronous operation has completed or not. A completed operation will
       result in data appearing as "read ready" on the file descriptor (no
       actual data should be read from the file descriptor). This function
       should only be called if the SSL object is currently waiting for
       asynchronous work to complete (i.e.  SSL_ERROR_WANT_ASYNC has been
       received - see SSL_get_error(3)). Typically the list will only contain
       one file descriptor. However, if multiple asynchronous capable engines
       are in use then more than one is possible. The number of file
       descriptors returned is stored in *numfds and the file descriptors
       themselves are in *fds. The fds parameter may be NULL in which case no
       file descriptors are returned but *numfds is still populated. It is the
       callers responsibility to ensure sufficient memory is allocated at *fds
       so typically this function is called twice (once with a NULL fds
       parameter and once without).
       SSL_get_changed_async_fds() returns a list of the asynchronous file
       descriptors that have been added and a list that have been deleted
       since the last SSL_ERROR_WANT_ASYNC was received (or since the SSL
       object was created if no SSL_ERROR_WANT_ASYNC has been received).
       Similar to SSL_get_all_async_fds() it is the callers responsibility to
       ensure that *addfd and *delfd have sufficient memory allocated,
       although they may be NULL. The number of added fds and the number of
       deleted fds are stored in *numaddfds and *numdelfds respectively.
RETURN VALUES
       SSL_waiting_for_async() will return 1 if the current SSL operation is
       waiting for an async operation to complete and 0 otherwise.
       SSL_get_all_async_fds() and SSL_get_changed_async_fds() return 1 on
       success or 0 on error.
NOTES
       On Windows platforms the openssl/async.h header is dependent on some of
       the types customarily made available by including windows.h. The
       application developer is likely to require control over when the latter
       is included, commonly as one of the first included headers. Therefore,
       it is defined as an application developer's responsibility to include
       windows.h prior to async.h.
SEE ALSO
       SSL_get_error(3), SSL_CTX_set_mode(3)
HISTORY
       The SSL_waiting_for_async(), SSL_get_all_async_fds() and
       SSL_get_changed_async_fds() functions were added in OpenSSL 1.1.0.
COPYRIGHT
       Copyright 2016-2020 The OpenSSL Project Authors. All Rights Reserved.
       Licensed under the OpenSSL license (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>;.
1.1.1k                            2021-03-25          SSL_GET_ALL_ASYNC_FDS(3)