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I have a c++ class and a member function uses two double array as input like:

class model{
//define some varible..
void Trainmodel(double *x,double *y);
//...
};

I wanted to use this class in c# and followed the example in ./swigwin2.0.9/examples/csharp/arrays and the guide in help page: SWIG my model.MY file is like:

%module model_dll 
%{
/* Includes the header in the wrapper code */
#include "model.h"
%}
/* Parse the header file to generate wrappers */
%include "model.h"
%include "arrays_csharp.i"
%apply double INPUT[]  { double* x }
%apply double INPUT[] { double* y }

but when I use this function in c#, an error occurs: Error 1 The best overloaded method match for model.Trainmodel(SWIGTYPE_p_double, SWIGTYPE_p_double) has some invalid arguments and Error 2 Argument 1: cannot convert from double[] to SWIGTYPE_p_double

I check the source code of model.cs and found the trainmodel function like this:

public int Trainmodel(SWIGTYPE_p_double x, SWIGTYPE_p_double y) {
//do something
}

could anyone help me figure out what's wrong with these codes? Why swig generate SWIGTYPE_p_double instead of double []?

I copy the example code in SWIG below:

c# code:

int[] source = { 1, 2, 3 };
int[] target = new int[ source.Length ];

example.myArrayCopy( source, target, target.Length );

c code:

void myArrayCopy( int* sourceArray, int* targetArray, int nitems ) {
int i;
for ( i = 0; i < nitems; i++ ) {
targetArray[ i ] = sourceArray[ i ];
}
}

.i warp file:

%include "arrays_csharp.i"
%apply int INPUT[]  {int *sourceArray}
%apply int OUTPUT[] {int *targetArray}

am I missing something?

SORRY I made such a stupid mistake.(WTF! :-( ) in the *.i file, the code " %include "model.h" " should put after these code "%include "arrays_csharp.i" %apply ..." not before. So the right form is:

%module model_dll 
%{
/* Includes the header in the wrapper code */
#include "model.h"
%}
/* Parse the header file to generate wrappers */
%include "arrays_csharp.i"
%apply double INPUT[]  { double* x }
%apply double INPUT[] { double* y }
%include "model.h"//BE CAREFUL: this should put after the include"arrays_csharp.i"

the problem is solved. and anyone who want include arrays_csharp.i, please make sure the "include" code and the "apply" code is written before include your own .h file (model.h in this case).

Luyi Tian
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  • I cant see any double array in yoir c++ code or am I wrong? You can also import your C++ dll without swig over DllImport in c# – Tearsdontfalls Jan 03 '13 at 07:27
  • *x *y are pointers point to two double array – Luyi Tian Jan 03 '13 at 07:35
  • Im not developing in C++, but I tought so and I got a kind of confirmation here http://stackoverflow.com/questions/1719051/array-of-pointers-as-function-parameter that the x and y pointers arent arrays, but it can still be that im wrong, but I would suggest to try to change `(double *x, double *y)` to `(*double x[], *double y[])` – Tearsdontfalls Jan 03 '13 at 15:02

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