#include <stdbool.h>
//It is same with util Library
-bool sstu_set_font_config(char *font_name);
-int sstu_is_available_font(char *font_name);
+bool sstu_set_font_config(const char *font_name);
+int sstu_is_available_font(const char *font_name);
char* sstu_get_default_font();
-bool sstu_is_valid_image(char *path);
+bool sstu_is_valid_image(const char *path);
void sstu_set_font_size();
void sstu_font_config_set_notification();