diff --git a/include/asterisk/pbx.h b/include/asterisk/pbx.h
index 41dd0d4415230410e7f79317a9fc051ebe1b2d19..3ff142e637132d1658fd1d188fb42c01e59a726f 100644
--- a/include/asterisk/pbx.h
+++ b/include/asterisk/pbx.h
@@ -865,12 +865,12 @@ int ast_custom_function_unregister(struct ast_custom_function *acf);
 /*!
  * \brief Register a custom function
  */
-#define ast_custom_function_register(acf) ast_custom_function_register2(acf, ast_module_info->self)
+#define ast_custom_function_register(acf) __ast_custom_function_register(acf, ast_module_info->self)
 
 /*!
  * \brief Register a custom function
  */
-int ast_custom_function_register2(struct ast_custom_function *acf, struct ast_module *mod);
+int __ast_custom_function_register(struct ast_custom_function *acf, struct ast_module *mod);
 
 /*! 
  * \brief Retrieve the number of active calls
diff --git a/main/pbx.c b/main/pbx.c
index ee88a06159b70008d27ec4683d2ef765ddabfdb1..4d7ebbaba1c58db6cb422e5fdef33ecdee853c39 100644
--- a/main/pbx.c
+++ b/main/pbx.c
@@ -1410,7 +1410,7 @@ int ast_custom_function_unregister(struct ast_custom_function *acf)
 	return acf ? 0 : -1;
 }
 
-int ast_custom_function_register2(struct ast_custom_function *acf, struct ast_module *mod)
+int __ast_custom_function_register(struct ast_custom_function *acf, struct ast_module *mod)
 {
 	struct ast_custom_function *cur;