//SWIG <-> Ruby - call by refrence for value types

[Sören Freudiger-2]

Hi @all
I'm pretty new to SWIG and Ruby and have a question.

--------------------
C++:
class A {
public:
 foo(int& var){ var+=10;}
};
--------------------

--------------------
Ruby:
var = 10
a = Example::A.new()
a.foo(var)
--------------------

results in: error --> Expected argument 1 of type int &, but got Fixnum 10
(TypeError)

How can I fix that problem. Our C++ code I have to write a ruby interface
for uses a huge number of methods like that...

Best regards,
SirAnn


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[James17]

Sören Freudiger-2 wrote:

--------------------
C++:
class A {
public:
 foo(int& var){ var+=10;}
};
--------------------
Ruby:
var = 10
a = Example::A.new()
a.foo(var)
--------------------

results in: error --> Expected argument 1 of type int &, but got Fixnum 10
(TypeError)

You are trying to pass an integer value when the C++ function is asking for an integer reference.  What to do about it probably depends upon what the integer is used for in the function... but it will come down to defining a typemap to convert a Ruby value properly.

[Sören Freudiger-2]

Okay, I got it. Somehow.

My example.i (just for a global foo-function):
----------------------------
/* File : example.i */
%module example
%{
#include "example.h"
%}
%include "typemaps.i"
void foo(int& INOUT);
----------------------------

example.h
----------------------------
void foo(int& val) { val +=10; }
----------------------------

run.rb
----------------------------
require 'example'
var = 7
var = Example::foo(var)
p var
----------------------------

Works fine. Is there a way to map ALL "int&" to "int& INOUT" automatically?

Something like " %apply int& {int& INOUT)}"???
That would simplifying the rest. Only if no INOUT is wished the interface has to be described in ".i"

Best,
SirAnn



-----Ursprüngliche Nachricht-----
Von: James17 [mailto:james.d.masters@...]
Gesendet: Montag, 9. November 2009 16:27
An: swig-user@...
Betreff: Re: [Swig-user] //SWIG <-> Ruby - call by refrence for value types




Sören Freudiger-2 wrote:

>
> --------------------
> C++:
> class A {
> public:
>  foo(int& var){ var+=10;}
> };
> --------------------
> Ruby:
> var = 10
> a = Example::A.new()
> a.foo(var)
> --------------------
>
> results in: error --> Expected argument 1 of type int &, but got Fixnum 10
> (TypeError)
>

You are trying to pass an integer value when the C++ function is asking for
an integer reference.  What to do about it probably depends upon what the
integer is used for in the function... but it will come down to defining a
typemap to convert a Ruby value properly.
--
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Sent from the swig-user mailing list archive at Nabble.com.


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