从c#中调用函数更改fortran中的参考参数值

Question

我有一个用fortran编写的dll，其中包含一个以逻辑参数作为输入的子例程。我希望使用它来控制子例程的取消，并且有可能在调用c#代码中更改它的值。下面是我测试过的一个小例子。

C#代码：

using System;
using System.Runtime.InteropServices;
using System.Threading;
using System.Threading.Tasks;

namespace TestConsApp
{
    internal static class Program
    {
        private static bool _b;
        [DllImport(dllName: "TestFortran.dll", CallingConvention = CallingConvention.Cdecl)]
        internal static extern void TestBool(ref bool b);


        private static void Main(string[] args)
        {    
            TestFortranBool();
            Console.ReadLine();
        }


        private static void TestFortranBool()
        {
            _b = true;
            var t = Task.Factory.StartNew(() => TestBool(ref _b));
            Console.WriteLine($"C# :{_b}");
            Thread.Sleep(5000);
            _b = false;
            Console.WriteLine($"C# :{_b}");
            Thread.Sleep(5000);
            _b = true;
            Console.WriteLine($"C# :{_b}");
            Thread.Sleep(5000);
            _b = false;
            Console.WriteLine($"C# :{_b}");
            Thread.Sleep(5000);
            _b = true;
            Console.WriteLine($"C# :{_b}");

            t.Wait();
        }
    }
}

和fortran代码：

module FortranTesting
  use iso_c_binding
  implicit none
contains
  
  
  subroutine TestBool(b)

  ! Expose subroutine TestFortran to users of this DLL
  !
  !DEC$ ATTRIBUTES DLLEXPORT::TestBool
  !DEC$ ATTRIBUTES DECORATE,ALIAS:"TestBool" :: TestBool
  
  logical(c_bool),intent(in) ::  b
  write(*,*) "Inside fortran"
  write(*,*) "F :", b
  call sleep(5)
  write(*,*) "F : ", b
  call sleep(5)
  write(*,*) "F : ", b
  call sleep(5)
  write(*,*) "F : ", b
  
  end subroutine TestBool
end module FortranTesting

我从中得到的是：

C#：真 内福特兰 F:T C#：假 F:T C#：真 F:T C#：假 F:T C#：真

我想要的是F (fortran)与C#交替使用。在从C#读取变量和在Fortran中更改变量时，我尝试了相反的方法，而Fortran的工作原理是预期的。

Answer 1

我终于找到了解决取消的办法。我给出了一个示例代码，它向fortran代码返回一个值(因此可以用来取消fortran子例程/函数)：

c#代码：

using System;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace TestConsApp
{
    internal static class Program
    {
        [DllImport(dllName: "TestFortran.dll", CallingConvention = CallingConvention.Cdecl)]
        internal unsafe static extern void TestCallBack([MarshalAs(UnmanagedType.FunctionPtr)] ActionRefInt callBack);

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        public delegate void ActionRefInt(ref int i);


        private static void Main(string[] args)
        {
            TestCallBack();
            Console.ReadLine();
        }

        private static void TestCallBack()
        {
            var callbackHandler = new ActionRefInt(OnCallBackInt);
            TestCallBack(callbackHandler);
        }

        private static void OnCallBackInt(ref int i)
        {
            Console.WriteLine($"C#: Value before change: {i}");
            i++;
            Console.WriteLine($"C#: Value after change: {i}");
        }

    }
}

和Fortran代码：

  module FortranTesting
  use iso_c_binding
  implicit none

  contains

  subroutine TestCallBack(callBack)
  !DEC$ ATTRIBUTES DLLEXPORT::TestCallBack
  !DEC$ ATTRIBUTES DECORATE,ALIAS:"TestCallBack" :: TestCallBack
  external        ::  callBack
  integer         ::  test
  
  test  = 1
  write(*,*) "F: Test before callback: ", test
  call callBack(test)
  write(*,*) "F: Test after callback: ", test
  end subroutine TestCallBack
  end module FortranTesting

此代码产生以下输出：

F:回调前的测试:1 C#：变化前的价值:1 C#：更改后的值:2 F:回调后的测试:2

Answer 2

我不认识C#，所以我不能帮你。但是，只要您可以将C#与C接口，也有一种方法可以将Fortran代码连接到C#。为此，必须将bind(C)属性添加到Fortran代码中，

module FortranTesting
    use iso_c_binding
    implicit none
contains
    subroutine TestBool(b) bind(C, name = "TestBool")
        ! Expose subroutine TestFortran to users of this DLL
        !DEC$ ATTRIBUTES DLLEXPORT :: TestBool

        use, intrinsic :: iso_c_binding, only: c_bool
        implicit none
        logical(c_bool), intent(in) ::  b

        write(*,*) "Inside Fortran:"
        write(*,*) "F :", b
        call sleep(5)
        write(*,*) "F : ", b
        call sleep(5)
        write(*,*) "F : ", b
        call sleep(5)
        write(*,*) "F : ", b

    end subroutine TestBool
end module FortranTesting

这段代码现在应该可以从C调用为TestBool(b)，并带有一个具有_Bool类型的输入参数b。