} sptps_t;
extern unsigned int sptps_replaywin;
-extern void sptps_log_quiet(sptps_t *s, int s_errno, const char *format, va_list ap);
-extern void sptps_log_stderr(sptps_t *s, int s_errno, const char *format, va_list ap);
-extern void (*sptps_log)(sptps_t *s, int s_errno, const char *format, va_list ap);
+extern void sptps_log_quiet(sptps_t *s, int s_errno, const char *format, va_list ap) ATTR_FORMAT(printf, 3, 0);
+extern void sptps_log_stderr(sptps_t *s, int s_errno, const char *format, va_list ap) ATTR_FORMAT(printf, 3, 0);
+extern void (*sptps_log)(sptps_t *s, int s_errno, const char *format, va_list ap) ATTR_FORMAT(printf, 3, 0);
extern bool sptps_start(sptps_t *s, void *handle, bool initiator, bool datagram, ecdsa_t *mykey, ecdsa_t *hiskey, const void *label, size_t labellen, send_data_t send_data, receive_record_t receive_record);
extern bool sptps_stop(sptps_t *s);
extern bool sptps_send_record(sptps_t *s, uint8_t type, const void *data, uint16_t len);