diff --git a/buffet/main.cc b/buffet/main.cc
index fde5c86..0f2c6d0 100644
--- a/buffet/main.cc
+++ b/buffet/main.cc
@@ -61,7 +61,7 @@
   const auto log_path =
       base::StringPrintf("%s/buffet.%s",
                          logs_dir.c_str(),
-                         GetTimeAsString(::time(NULL)).c_str());
+                         GetTimeAsString(::time(nullptr)).c_str());
   mkdir(logs_dir.c_str(), 0755);
   SetupLogSymlink(log_symlink, log_path);
   return log_symlink;