unlink

/*
 *  call-seq:
 *     Dir.delete( string ) => 0
 *     Dir.rmdir( string ) => 0
 *     Dir.unlink( string ) => 0
 *
 *  Deletes the named directory. Raises a subclass of
 *  <code>SystemCallError</code> if the directory isn't empty.
 */
static VALUE
dir_s_rmdir(obj, dir)
    VALUE obj, dir;
{
    check_dirname(&dir);
    if (rmdir(RSTRING(dir)->ptr) < 0)
        rb_sys_fail(RSTRING(dir)->ptr);

    return INT2FIX(0);
}