SSL_CTX_sess_set_cache_size.3ssl man page

SSL_CTX_sess_set_cache_size, SSL_CTX_sess_get_cache_size — manipulate session cache size


#include <openssl/ssl.h>
long SSL_CTX_sess_set_cache_size(SSL_CTX *ctx, long t);
long SSL_CTX_sess_get_cache_size(SSL_CTX *ctx);


SSL_CTX_sess_set_cache_size() sets the size of the internal session cache of context ctx to t. This value is a hint and not an absolute; see the notes below.

SSL_CTX_sess_get_cache_size() returns the currently valid session cache size.


The internal session cache size is SSL_SESSION_CACHE_MAX_SIZE_DEFAULT, currently 1024*20, so that up to 20000 sessions can be held. This size can be modified using the SSL_CTX_sess_set_cache_size() call. A special case is the size 0, which is used for unlimited size.

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 SSL_CTX_flush_sessions(3) to remove expired sessions.

If the size of the session cache is reduced and more sessions are already in the session cache, old session will be removed at the next time a session shall be added. This removal is not synchronized with the expiration of sessions.

Return Values

SSL_CTX_sess_set_cache_size() returns the previously valid size.

SSL_CTX_sess_get_cache_size() returns the currently valid size.

See Also

ssl(3), SSL_CTX_set_session_cache_mode(3), SSL_CTX_sess_number(3), SSL_CTX_flush_sessions(3)