diff --git a/src/Common/MemoryStatisticsOS.cpp b/src/Common/MemoryStatisticsOS.cpp
index 22f8446121f..f2d2ab5fea9 100644
--- a/src/Common/MemoryStatisticsOS.cpp
+++ b/src/Common/MemoryStatisticsOS.cpp
@@ -135,7 +135,7 @@ MemoryStatisticsOS::Data MemoryStatisticsOS::get() const
     struct kinfo_proc kp;
     size_t len = sizeof(struct kinfo_proc);
 
-    if (-1 == ::sysctl(mib, 4, &kp, &len, NULL, 0))
+    if (-1 == ::sysctl(mib, 4, &kp, &len, nullptr, 0))
         throwFromErrno("Cannot sysctl(kern.proc.pid." + std::to_string(self) + ")", ErrorCodes::SYSTEM_ERROR);
 
     if (sizeof(struct kinfo_proc) != len)