libssh2_session_callback_set - set a callback function
void * libssh2_session_callback_set(LIBSSH2_SESSION *session, int
cbtype, void *callback);
session - Session instance as returned by libssh2_session_init_ex(3)
cbtype - Callback type. One of the types listed in Callback Types.
callback - Pointer to custom callback function. The prototype for this
function must match the associated callback declaration macro.
Sets a custom callback handler for a previously initialized session
object. Callbacks are triggered by the receipt of special packets at
the Transport layer. To disable a callback, set it to NULL.
Pointer to previous callback handler. Returns NULL if no prior callback
handler was set.