added interrupt capability
diff --git a/includes/gpio.h b/includes/gpio.h
index 54d912d..d9279e4 100644
--- a/includes/gpio.h
+++ b/includes/gpio.h
@@ -25,6 +25,7 @@
 int gpio_init(GDBusConnection*, GPIO*);
 void gpio_close(GPIO*);
 int  gpio_open(GPIO*);
+int gpio_open_interrupt(GPIO*, GIOFunc, gpointer);
 int gpio_write(GPIO*, uint8_t);
 int gpio_writec(GPIO*, char);
 int gpio_clock_cycle(GPIO*, int);