#ifdef LOGD
#undef LOGD
#endif
-#define LOGD(arg...) do {fprintf(log_file, ##arg);fprintf(log_file, "\n"); fflush(log_file);} while(0)
+#define LOGD(arg...) do {if (log_file) {fprintf(log_file, ##arg);fprintf(log_file, "\n"); fflush(log_file);}} while(0)
#endif