diff --git a/include/common/standard.h b/include/common/standard.h
index 9abdb06..353d0b0 100644
--- a/include/common/standard.h
+++ b/include/common/standard.h
@@ -860,9 +860,6 @@
 
 extern const char *monthname[];
 
-/* numeric timezone (that is, the hour and minute offset from UTC) */
-char localtimezone[6];
-
 /* date2str_log: write a date in the format :
  * 	sprintf(str, "%02d/%s/%04d:%02d:%02d:%02d.%03d",
  *		tm.tm_mday, monthname[tm.tm_mon], tm.tm_year+1900,
@@ -873,6 +870,12 @@
  */
 char *date2str_log(char *dest, struct tm *tm, struct timeval *date, size_t size);
 
+/* Return the GMT offset for a specific local time.
+ * The string returned has the same format as returned by strftime(... "%z", tm).
+ * Offsets are kept in an internal cache for better performances.
+ */
+const char *get_gmt_offset(struct tm *tm);
+
 /* gmt2str_log: write a date in the format :
  * "%02d/%s/%04d:%02d:%02d:%02d +0000" without using snprintf
  * return a pointer to the last char written (\0) or