diff --git a/libc/async_safe/async_safe_log.cpp b/libc/async_safe/async_safe_log.cpp
index c6b8b53..5f22c74 100644
--- a/libc/async_safe/async_safe_log.cpp
+++ b/libc/async_safe/async_safe_log.cpp
@@ -333,7 +333,7 @@
     if (c == 's') {
       /* string */
       str = va_arg(args, const char*);
-      if (str == NULL) {
+      if (str == nullptr) {
         str = "(null)";
       }
     } else if (c == 'c') {