diff --git a/runtime/syntax/cpp.yaml b/runtime/syntax/cpp.yaml
index 3c97b2c4..e84c3cd4 100644
--- a/runtime/syntax/cpp.yaml
+++ b/runtime/syntax/cpp.yaml
@@ -1,7 +1,8 @@
 filetype: c++
 
 detect:
-    filename: "(\\.c(c|pp|xx)$|\\.h(h|pp|xx)$|\\.ii?$|\\.(def)$)"
+    filename: "(\\.c(c|pp|xx)$|\\.h(h|pp|xx)?$|\\.ii?$|\\.(def)$)"
+    signature: "namespace|template|public|protected|private"
 
 rules:
     - identifier: "\\b[A-Z_][0-9A-Z_]*\\b"