diff --git a/compiler/cpp/src/main.h b/compiler/cpp/src/main.h
index cb6d27a..46ad835 100644
--- a/compiler/cpp/src/main.h
+++ b/compiler/cpp/src/main.h
@@ -58,6 +58,11 @@
 void failure(const char* fmt, ...);
 
 /**
+ * Check simple identifier names
+ */
+void validate_simple_identifier(const char* identifier);
+
+/**
  * Check constant types
  */
 void validate_const_type(t_const* c);