From help-octave-request at bevo dot che dot wisc dot edu  Wed Jan 31 02:24:54 2001
Subject: Re:  Basic questions regarding liboctave and dynamic function development
From: Etienne Grossmann <etienne at anonimo dot isr dot ist dot utl dot pt>
To: help-octave at bevo dot che dot wisc dot edu, Jrigler@colorado.edu
CC: etienne at isr dot ist dot utl dot pt
Date: Wed, 31 Jan 2001 08:28:25 +0000


  Hello,

From: Joshua Rigler <Jrigler at colorado dot edu>
#  Keeping in mind that I am fairly fluent in C, but know virtually nothing
#  about object oriented programming or C++, please forgive my ignorance...

#  1) What exactly is liboctave (for what, and how is it used)? How do I
#  interpret the documentation for liboctave found in liboctave.ps? (part
#  of the Octave distribution docs)  

#  2) Is liboctave.ps supposed to describe all functions that should be
#  available to me when I write .oct functions? (It doesn't...for example I
#  have no idea what the function "matrix_value" does (found in lu.cc), the
#  docs for liboctave say nothing about it, and I see no explanation in the
#  header file or source code).

  I am no octave or C++ expert, but, in src/DLD-FUNCTIONS/lu.cc, there
is  

  octave_value arg = args(0);      // Put argument to lu in a
                                   // variable. At this point, you
                                   // don't know what the arg is.  

      ...                         // Check that a square matrix has
                                  // been passed   

  Matrix m = arg.matrix_value (); // Make a matrix out of it. (a
                                  // variable of class Matrix). You
                                  // can then use Matrix methods on m.

  When implementing c++ functions for octave, I never got beyond
"looking at how other functions are done and copying". Also asking on
this list when you have a specific problem may help.

#  3) Any suggestions for how somebody who understands C, but has no
#  object-oriented programming experience, and only a basic understanding
#  of C++ syntax can figure out how to write some .oct functions to make
#  calls to a C library?  Is there a trick to including a C header file in
#  a C++ program?

  Sorry, I never touched .oct functions

#  I won't go so far as to ask for a basics of C++ lesson, but if anyone
#  could help me get just a rudimentary understanding of how things work in
#  Octave, I should be able to put together a nice CDF I/O package for
#  Octave fairly quickly.

  Hth a little bit,

  Etienne



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