identical (the SSL_SESSION object is identical), SSL_CTX_add_session()
is a no-op, and the return value is 0.
+If a server SSL_CTX is configured with the SSL_SESS_CACHE_NO_INTERNAL_STORE
+flag then the internal cache will not be populated automatically by new
+sessions negotiated by the SSL/TLS implementation, even though the internal
+cache will be searched automatically for session-resume requests (the
+latter can be surpressed by SSL_SESS_CACHE_NO_INTERNAL_LOOKUP). So the
+application can use SSL_CTX_add_session() directly to have full control
+over the sessions that can be resumed if desired.
+
=head1 RETURN VALUES