-void snd_opl4_synth_reset(opl4_t *opl4);
-void snd_opl4_synth_shutdown(opl4_t *opl4);
-void snd_opl4_note_on(void *p, int note, int vel, snd_midi_channel_t *chan);
-void snd_opl4_note_off(void *p, int note, int vel, snd_midi_channel_t *chan);
-void snd_opl4_terminate_note(void *p, int note, snd_midi_channel_t *chan);
-void snd_opl4_control(void *p, int type, snd_midi_channel_t *chan);
-void snd_opl4_sysex(void *p, unsigned char *buf, int len, int parsed, snd_midi_channel_set_t *chset);
+void snd_opl4_synth_reset(struct snd_opl4 *opl4);
+void snd_opl4_synth_shutdown(struct snd_opl4 *opl4);
+void snd_opl4_note_on(void *p, int note, int vel, struct snd_midi_channel *chan);
+void snd_opl4_note_off(void *p, int note, int vel, struct snd_midi_channel *chan);
+void snd_opl4_terminate_note(void *p, int note, struct snd_midi_channel *chan);
+void snd_opl4_control(void *p, int type, struct snd_midi_channel *chan);
+void snd_opl4_sysex(void *p, unsigned char *buf, int len, int parsed, struct snd_midi_channel_set *chset);