On 10/06/2019 15:21, J. J. Farrell wrote: > |void SSL_CTX_sess_set_new_cb(SSL_CTX *ctx, int (*new_session_cb)(SSL *, > SSL_SESSION *));| > > > How do we specify a user-defined callback data pointer in that call? You don't; you additionally use SSL_CTX_set_msg_callback_arg() which the OP said he was already using. -- Cheers, Jeremy