diff --git a/src/ui.c b/src/ui.c
index 3cd5699..90417ea 100644
--- a/src/ui.c
+++ b/src/ui.c
@@ -11,12 +11,10 @@
 #include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
-#define _POSIX_THREAD_SAFE_FUNCTIONS
 #include <time.h>
-#include <time.h>
-#if defined(_MSC_VER)
-#define localtime_r(T,Tm) (localtime_s(Tm,T) NULL:Tm)
-#endif
+
+#define localtime_r(T,Tm) (localtime_s(Tm,T) ? NULL:Tm)
+
 
 const char *dbName = "db.csv";