Communicating between Fortran and C#

[pradeepnatekar]

Hi

Please let me know how to handle data type sending and receiving from C# to Fortran dll. I have come across some samples from VB and Fortran communication but not really specific to C#. I want to pass specific data from C# as inputarray to routine inFortran dll and receive some resultsas array from same Fortran dll after processing it.

Any help is appreciated.

Pradeep

[Steven_L_Intel1]

Attached is a C# sample. It may be of some help. Arrays can be tricky, if you don't want to get into added complexity, you can pass arrayname[0] (or whatever the first element is and Fortran should be able to pick it up. Remember that Fortran and C/C# index arrays differently.

[pradeepnatekar]

Many thanks steve,

I have built the applivation with CVF as we will receive IVF in 2-3 days.

I am surprised to see following error which I guess is related to array type mismatch. Please correct me as I am not sure about the error.

I have created another sample application but there also no success. I will be grateful ifyou send me your email id so that I send the attachment as I am not able to attachthe file as per security policy here.

Thanks Pradeep

pradeepkumar.natekar@tcs.com

This is the error in application you sent:

489.7500
a
233.7500

Unhandled Exception: System.NullReferenceException: Object reference not set to
an instance of an object.
at ConsoleApplication4.Class1.visualfortranDll1(Single r1, Single& num, Strin
gBuilder nnn, Int32[] arr, Int32 aLen, StringBuilder outstr, Int32 len, Int32 ou
tlen)
at ConsoleApplication4.Class1.Main(String[] args) in c:documents and setting
s135482desktopcsharpsamplecsharpsampleconsoleapplication4class1.cs:line 36

[Steven_L_Intel1]

The sample I sent you was for Intel Visual Fortran. I don't know what if anything would need to change when using CVF. If it still fails with Intel Fortran, let me know.

[pradeepnatekar]

Hi,

I will check that code once we have IVF. I tried one simple code given below which really works without handling unmanaged types. I don't know whether to proceed with this one or one which you have written. Please let me know the difference between two.

Fortran code to build DllTest.dll:

SUBROUTINE SUB1(A,N)

!DEC$ ATTRIBUTES DLLEXPORT :: SUB1
!DEC$ ATTRIBUTES C, ALIAS :'SUB1':: SUB1

REAL A(N),B(N)

DO 100 I=1,N
WRITE (*,*) A(I)
B(I) = A(I)*2
100 CONTINUE
END SUBROUTINE SUB1

C# code to call the dll :

using System;

using System.Runtime.InteropServices;

namespace CallF77Dll

{

///

/// Summary description for Class1.

///

class Class1

{

[DllImport("DllTest.dll")]

public static extern void SUB1(float[] A,int N);

static void Main(string[] args)

{

float[] A = {1.1F,2.2F,3.3F,4.4F,5.5F};

float[] B;

int N = A.Length;

SUB1(A,N);

}

}

}

Thanks & Regards,

Pradeep

[Steven_L_Intel1]

To be honest, I don't know. If what you have works, that's great. Maybe the additional types used in the sample I provided (which is based on something from a customer) requires the MarshallAs stuff. Clearly I have some learning to do about C#.

[pradeepnatekar]

I am also in learning phase so not aware of managed/unmanaged handling. I will keep a post if I succeed in handling with managed thing only.

Thanks & Regards

Pradeep