1 files changed, 2 insertions, 2 deletions
diff --git a/op.h b/op.h
index e92b1d8db4..e55d5465ff 100644
--- a/op.h
+++ b/op.h
@@ -464,7 +464,7 @@ struct loop {
 typedef struct {
   struct tm* tmbuff;
 } REBUF;
-#define localtime(a)       localtime_r(a,PL_reentrant_buffer->tmbuff)
-#define gmtime(a)          gmtime_r(a,PL_reentrant_buffer->tmbuff)
+#define localtime(a)       (localtime_r(a,PL_reentrant_buffer->tmbuff) && PL_reentrant_buffer->tmbuff)
+#define gmtime(a)          (gmtime_r(a,PL_reentrant_buffer->tmbuff) && PL_reentrant_buffer->tmbuff)
 #endif