#include <stdarg.h>
#include <stddef.h>
-extern int ust_safe_vsnprintf(char *str, size_t n, const char *fmt, va_list ap);
-extern int ust_safe_snprintf(char *str, size_t n, const char *fmt, ...);
+__attribute__((visibility("hidden")))
+int ust_safe_vsnprintf(char *str, size_t n, const char *fmt, va_list ap);
+
+__attribute__((visibility("hidden")))
+int ust_safe_snprintf(char *str, size_t n, const char *fmt, ...)
+ __attribute__ ((format (printf, 3, 4)));
#endif /* UST_SNPRINTF */