diff --git a/luna/src/CString.cpp b/luna/src/CString.cpp
index b853c471..e1ba020e 100644
--- a/luna/src/CString.cpp
+++ b/luna/src/CString.cpp
@@ -49,7 +49,7 @@ extern "C"
     usize strnlen(const char* str, usize max)
     {
         const char* i = str;
-        for (; max, *i; ++i, --max)
+        for (; *i && max; ++i, --max)
             ;
         return (usize)(i - str);
     }