ags_synth_callbacks
void ags_synth_auto_update_callback (GtkCheckButton *check_button, AgsSynth *synth);
GtkCheckButton *check_button
AgsSynth *synth
void ags_synth_update_callback (GtkButton *button, AgsSynth *synth);
GtkButton *button
void ags_synth_lower_callback (GtkSpinButton *spin_button, AgsSynth *synth);
GtkSpinButton *spin_button