int snd_seq_drain_input_buffer(snd_seq_t *handle);
int snd_seq_drain_input_buffer
Removes all events on user-space input FIFO. Unlike snd_seq_drain_input, this doesn't remove events on input FIFO of sequencer on kernel space.
Function returns zero if successful, or a negative error code.
snd_seq_drain_input, snd_seq_remove_events