file.c:1755
VALUE
rb_file_s_expand_path(argc, argv)
    int argc;
    VALUE *argv;
{
    VALUE fname, dname;

    if (argc == 1) {
	return rb_file_expand_path(argv[0], Qnil);
    }
    rb_scan_args(argc, argv, "11", &fname, &dname);

    return rb_file_expand_path(fname, dname);
}
