When this option is set, the FileType autocommand event is triggered. All autocommands that match with the value of this option will be executed. Thus the value of 'filetype' is used in place of the file name. Otherwise this option does not always reflect the current file type. This option is normally set when the file type is detected. To enable this use the ":filetype on" command. |:filetype| Setting this option to a different value is most useful in a modeline, for a file for which the file type is not automatically recognized. Example, for in an IDL file: // ~ |FileType| |filetypes| When a dot appears in the value then this separates two filetype names. Example: // ~ This will use the "c" filetype first, then the "doxygen" filetype. This works both for filetype plugins and for syntax files. More than one dot may appear. This option is not copied to another buffer, independent of the 's' or 'S' flag in 'cpoptions'. Only normal file name characters can be used, "/*?[|<>" are illegal.