extern int smtp_fflush(void);
extern void smtp_printf(const char *, BOOL, ...) PRINTF_FUNCTION(1,3);
extern void smtp_vprintf(const char *, BOOL, va_list);
-extern uschar *string_sprintf(const char *, ...) ALMOST_PRINTF(1,2);
+
+#define string_sprintf(fmt, ...) \
+ string_sprintf_trc(fmt, US __FUNCTION__, __LINE__, __VA_ARGS__)
+extern uschar *string_sprintf_trc(const char *, const uschar *, unsigned, ...) ALMOST_PRINTF(1,4);
#ifdef LOCAL_SCAN
/* When compiling a local_scan() file we want to rename a published API, so that