.\"	$OpenBSD: SSL_CTX_flush_sessions.3,v 1.5 2018/03/27 17:35:50 schwarze Exp $
.\"	OpenSSL SSL_CTX_flush_sessions.pod 1722496f Jun 8 15:18:38 2017 -0400
.\"
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.Dd $Mdocdate: March 27 2018 $
.Dt SSL_CTX_FLUSH_SESSIONS 3
.Os
.Sh NAME
.Nm SSL_CTX_flush_sessions
.Nd remove expired sessions
.Sh SYNOPSIS
.In openssl/ssl.h
.Ft void
.Fn SSL_CTX_flush_sessions "SSL_CTX *ctx" "long tm"
.Sh DESCRIPTION
.Fn SSL_CTX_flush_sessions
causes a run through the session cache of
.Fa ctx
to remove sessions expired at time
.Fa tm .
.Pp
If enabled, the internal session cache will collect all sessions established
up to the specified maximum number (see
.Xr SSL_CTX_sess_set_cache_size 3 ) .
As sessions will not be reused once they are expired, they should be
removed from the cache to save resources.
This can either be done automatically whenever 255 new sessions were
established (see
.Xr SSL_CTX_set_session_cache_mode 3 )
or manually by calling
.Fn SSL_CTX_flush_sessions .
.Pp
The parameter
.Fa tm
specifies the time which should be used for the
expiration test, in most cases the actual time given by
.Fn time 0
will be used.
.Pp
.Fn SSL_CTX_flush_sessions
will only check sessions stored in the internal cache.
When a session is found and removed, the
.Va remove_session_cb
is however called to synchronize with the external cache (see
.Xr SSL_CTX_sess_set_get_cb 3 ) .
.Sh SEE ALSO
.Xr ssl 3 ,
.Xr SSL_CTX_sess_set_get_cb 3 ,
.Xr SSL_CTX_set_session_cache_mode 3 ,
.Xr SSL_CTX_set_timeout 3
.Sh HISTORY
.Fn SSL_CTX_flush_sessions
first appeared in SSLeay 0.8.0 and has been available since
.Ox 2.4 .