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// hello.cc -- example of a dynamically linked function for Octave.
// To use this file, your version of Octave must support dynamic
// linking. To find out if it does, type the command
//
// x = octave_config_info; x.DEFS
//
// at the Octave prompt. Support for dynamic linking is included if
// the output contains the string -DWITH_DYNAMIC_LINKING=1.
//
// To compile this file, type the command
//
// mkoctfile hello.cc
//
// at the shell prompt. The script mkoctfile should have been
// installed along with Octave. Running it will create a file called
// hello.oct that can be loaded by Octave. To test the hello.oct
// file, start Octave and type the command
//
// hello ("easy as", 1, 2, 3)
//
// at the Octave prompt. Octave should respond by printing
//
// Hello, world!
// easy as
// 1
// 2
// 3
// ans = 3
// Additional examples are available in the files in the src directory
// of the Octave distribution that use the macro DEFUN_DLD_BUILTIN.
// Currently, this includes the files
//
// balance.cc fft2.cc inv.cc qzval.cc
// chol.cc filter.cc log.cc schur.cc
// colloc.cc find.cc lsode.cc sort.cc
// dassl.cc fsolve.cc lu.cc svd.cc
// det.cc givens.cc minmax.cc syl.cc
// eig.cc hess.cc pinv.cc
// expm.cc ifft.cc qr.cc
// fft.cc ifft2.cc quad.cc
//
// The difference between DEFUN_DLD and DEFUN_DLD_BUILTIN is that
// DEFUN_DLD_BUILTIN can define a built-in function that is not
// dynamically loaded if the operating system does not support dynamic
// linking. To define your own dynamically linked functions you
// should use DEFUN_DLD.
#include <octave/config.h>
#include <iostream.h>
#include <octave/defun-dld.h>
#include <octave/error.h>
#include <octave/oct-obj.h>
#include <octave/pager.h>
#include <octave/symtab.h>
#include <octave/variables.h>
// DEFUN_DLD and the macros that it depends on are defined in the
// files defun-dld.h, defun.h, and defun-int.h.
// Note that the third parameter (nargout) is not used, so it is
// omitted from the list of arguments to DEFUN_DLD in order to avoid
// the warning from gcc about an unused function parameter.
DEFUN_DLD (hello, args, ,
"[...] = hello (...)\n\
\n\
Print greeting followed by the values of all the arguments passed.\n\
Returns all arguments in reverse order.")
{
// The list of values to return. See the declaration in oct-obj.h
octave_value_list retval;
// This stream is normally connected to the pager.
octave_stdout << "Hello, world!\n";
// The arguments to this function are available in args.
int nargin = args.length ();
// The octave_value_list class is a zero-based array of octave_value
// objects. The declaration for the octave_value class is in the
// file pt-const.h. The print() method will send its output to
// octave_stdout, so it will also end up going through the pager.
for (int i = 0; i < nargin; i++)
{
octave_value tmp = args (i);
tmp.print ();
retval (nargin-i-1) = tmp;
}
return retval;
}
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