TT_MAX_FILE_NAME_LENGTH
char f_name[TT_MAX_FILE_NAME_LENGTH];
snprintf(f_name, TT_MAX_FILE_NAME_LENGTH, "tz%d", tt_zone->id);
char d_name[TT_MAX_FILE_NAME_LENGTH];
snprintf(d_name, TT_MAX_FILE_NAME_LENGTH, "trip_%d_temp", tt_trip->id);
snprintf(d_name, TT_MAX_FILE_NAME_LENGTH, "trip_%d_hyst", tt_trip->id);