-extern void smtp_printf(char *, ...) PRINTF_FUNCTION;
-extern uschar *string_copy(uschar *);
-extern uschar *string_copyn(uschar *, int);
-extern uschar *string_sprintf(char *, ...);
+extern void smtp_printf(const char *, BOOL, ...) PRINTF_FUNCTION(1,3);
+extern void smtp_vprintf(const char *, BOOL, va_list);
+
+#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
+we can use an inlined implementation in the compiles of the main Exim files,
+with the original name. */
+
+# define string_copy(s) string_copy_function(s)
+# define string_copyn(s, n) string_copyn_function(s, n)
+
+extern uschar * string_copy_function(const uschar *);
+extern uschar * string_copyn_function(const uschar *);
+#endif