.\"	$OpenBSD: SSL_CTX_sess_set_cache_size.3,v 1.5 2019/06/12 09:36:30 schwarze Exp $
.\"	OpenSSL b97fdb57 Nov 11 09:33:09 2016 +0100
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.Dd $Mdocdate: June 12 2019 $
.Dt SSL_CTX_SESS_SET_CACHE_SIZE 3
.Os
.Sh NAME
.Nm SSL_CTX_sess_set_cache_size ,
.Nm SSL_CTX_sess_get_cache_size
.Nd manipulate session cache size
.Sh SYNOPSIS
.In openssl/ssl.h
.Ft long
.Fn SSL_CTX_sess_set_cache_size "SSL_CTX *ctx" "long t"
.Ft long
.Fn SSL_CTX_sess_get_cache_size "SSL_CTX *ctx"
.Sh DESCRIPTION
.Fn SSL_CTX_sess_set_cache_size
sets the size of the internal session cache of context
.Fa ctx
to
.Fa t .
.Pp
.Fn SSL_CTX_sess_get_cache_size
returns the currently valid session cache size.
.Pp
The internal session cache size is
.Dv SSL_SESSION_CACHE_MAX_SIZE_DEFAULT ,
currently 1024\(mu20, so that up to 20000 sessions can be held.
This size can be modified using the
.Fn SSL_CTX_sess_set_cache_size
call.
A special case is the size 0, which is used for unlimited size.
.Pp
If adding the session makes the cache exceed its size, then unused
sessions are dropped from the end of the cache.
Cache space may also be reclaimed by calling
.Xr SSL_CTX_flush_sessions 3
to remove expired sessions.
.Pp
If the size of the session cache is reduced and more sessions are already in
the session cache,
old session will be removed the next time a session shall be added.
This removal is not synchronized with the expiration of sessions.
.Sh RETURN VALUES
.Fn SSL_CTX_sess_set_cache_size
returns the previously valid size.
.Pp
.Fn SSL_CTX_sess_get_cache_size
returns the currently valid size.
.Sh SEE ALSO
.Xr ssl 3 ,
.Xr SSL_CTX_ctrl 3 ,
.Xr SSL_CTX_flush_sessions 3 ,
.Xr SSL_CTX_sess_number 3 ,
.Xr SSL_CTX_set_session_cache_mode 3
.Sh HISTORY
.Fn SSL_CTX_sess_set_cache_size
and
.Fn SSL_CTX_sess_get_cache_size
first appeared in SSLeay 0.9.0 and have been available since
.Ox 2.4 .