Among the preferences that you can set on the Preprocessor Integration page are whether to start the preprocessor automatically when a file is opened or saved or whether to start it manually by using the Source menu in the editor.
The Preprocessor Integration preference also provides settings that determine how preprocessor statements are identified by the editor. These settings help to distinguish preprocessor statements from comments or non-syntax text that is not a preprocessor statement.
You can open the Preprocessor Integration page from the menu bar or from an edit session.