modify in place

[John W. Eaton]

On 27-Nov-2000, Ben Sapp <address@hidden> wrote:

| How can I modify a variable that is a new user defined type?  I want to
| modify the actuall variable.  I do not want to make another modified
| instance of the variable.  I tried the following piece of code and it
| compiled fine but, ended up crashing on the line in
| "non_const_function()" where I modify some internal variables in
| myclass.  
| 
| ------------------------------------------------------------
| octave_value &rep = const_cast<octave_value&>(args(0).get_rep());
| octave_myclass &myclass = (octave_myclass &)(rep);
| myclass.non_const_function();
| -------------------------------------------------------------
| 
| I want it to work like this from the octave command line:
| 
| modify_in_place(a);
| 
| Now "modify_in_place" does not return any thing it just changes the
| value of "a".  

You can't without changing a fundamental feature of Octave, which
enforces pass by value semantics for function arguments.

jwe



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