diff --git a/driver/rsdSampler.cpp b/driver/rsdSampler.cpp
index 1a72fd4..28b594f 100644
--- a/driver/rsdSampler.cpp
+++ b/driver/rsdSampler.cpp
@@ -47,13 +47,13 @@
 {
     obj->p = alloc;
 #ifdef __LP64__
-    obj->r = NULL;
-    if (alloc != NULL) {
+    obj->r = nullptr;
+    if (alloc != nullptr) {
         obj->v1 = alloc->mHal.drv;
     } else {
-        obj->v1 = NULL;
+        obj->v1 = nullptr;
     }
-    obj->v2 = NULL;
+    obj->v2 = nullptr;
 #endif
 }