Add comment about strftimei()

goldlib/gall/gtimall.h

@@ -229,6 +229,8 @@ inline Clock gclock() { return Clock(clock()*10/CLK_TCK); }
 int str2mon(const char* ptr) __attribute__ ((const));
 int tzoffset();
 
+//  In differ to ANSI C strftime() the function strftimei() supports reloading of field names (loaded from language file).
+//  Return NULL if output truncated, otherwize return s.
 char* strftimei(char* s, size_t maxsize, const char* fmt, const struct tm* t); // __attribute__ ((format (strftime, 3, 0)));
 
 FTime    TimeToFTime(time32_t __time) __attribute__ ((const));

goldlib/gall/gtimutil.cpp

@@ -183,6 +183,7 @@ static void strfmt(char *str, const char *fmt, ...) {
 //  ------------------------------------------------------------------
 //  In differ to ANSI C strftime this function supports reloading of
 //  field names
+//  Return NULL if output truncated, otherwize return s.
 
 #define setvar(internal,external,field) \
   char **internal = external; \