Creates an event record for general purpose. The created event record is cleared by zero, i.e. the fixed length with the absolute scheduled time 0 on tick queue 0.
Note that for using a variable length event, the extra data must be alloced via malloc or its siblings. Otherwise the record can't be freed properly via snd_seq_free_event.
Function returns the pointer of event record if successful. If it can't create, NULL is returned.
You may pass even a static or temporal event record to snd_seq_event_output without using this function. This function is provided only for ease of programming. Usually it is faster to use a static event record than creating and freeing an event record at each time.