#### 11.9.3 Private Functions

In many cases one function needs to access one or more helper functions. If the helper function is limited to the scope of a single function, then subfunctions as discussed above might be used. However, if a single helper function is used by more than one function, then this is no longer possible. In this case the helper functions might be placed in a subdirectory, called "private", of the directory in which the functions needing access to this helper function are found.

As a simple example, consider a function `func1`, that calls a helper function `func2` to do much of the work. For example:

    function y = func1 (x)
      y = func2 (x);
    endfunction

Then if the path to `func1` is `<directory>/func1.m`, and if `func2` is found in the directory `<directory>/private/func2.m`, then `func2` is only available for use of the functions, like `func1`, that are found in `<directory>`.