This function returns filename converted to an absolute path name. If filename is relative, the function prepends the directory dir if that directory is given; otherwise, the current working directory is used to make filename absolute.

If filename starts with ~ or contains any variable references, the name is expanded by calling expand_file_name. If filename contains the %L symbolic parameter, the name is expanded by calling locale_file_name. Arbortext Editor simplifies file names containing . or .. as components.