more help with writing C++ functions for Octave

[John W. Eaton]

On  6-May-1998, Karen L. Kalat <address@hidden> wrote:

| I have a function successfully compiled that uses a C library 
| of my own. Now I'm trying to figure out how to "cast" octave-type variables
| to values with datatypes I can pass to my C functions.
| For example:
| If I read in a bunch of things in args how do I get a char* 
| out of arg(0)? 
| 
| octave:1> myfunction("charstring")

You can use something like

  DEFUN(myfunction, args, ,
    "help text"
  {
    octave_value retval;

    string arg = args(0).string_value;

    my_c_function (arg.c_str ());

    return retval;
  }

Of course, you might want to add some error checking too.

Take a look at the functions distributed with Octave for more
examples.  The list of functions that extract data from octave_value
objects are declared in the header file ov.h.

jwe