If the simple configuration function
OPENSSL_config() is called then OPENSSL_load_builtin_modules() is called automatically.Applications which use the configuration functions directly will need to call OPENSSL_load_builtin_modules() themselves before any other configuration code.
Applications should call OPENSSL_load_builtin_modules() to load all configuration modules instead of adding modules selectively: otherwise functionality may be missing from the application if an when new modules are added.