+SR_API int sr_sprintf_ascii(char *buf, const char *format, ...);
+SR_API int sr_vsprintf_ascii(char *buf, const char *format, va_list args);
+SR_API int sr_snprintf_ascii(char *buf, size_t buf_size,
+ const char *format, ...);
+SR_API int sr_vsnprintf_ascii(char *buf, size_t buf_size,
+ const char *format, va_list args);
+SR_API int sr_parse_rational(const char *str, struct sr_rational *ret);