从 C# 调用 FORTRAN dll 并将值分配给结构数组 [英] Calling FORTRAN dll from C# and assigning values to array of structures
问题描述
我可以将 C#
结构传递到 FORTRAN
就好了.我什至可以在 FORTRAN
中将 C#
结构的数组作为 TYPE()
的数组传递.我遇到麻烦的地方是当我试图将值返回到 C#
时.下面是一个例子:
I can pass a C#
struct into FORTRAN
just fine. I can even pass an array of a C#
struct as an array of TYPE()
in FORTRAN
. Where I run into trouble is when I tried to return values back into C#
. Here is an example:
fortran dll 是:
The fortran dll is:
MODULE TESTING
TYPE VALUEREF
INTEGER*4 :: A
ENDTYPE VALUEREF
CONTAINS
SUBROUTINE TEST_REF(T,N)
!DEC$ ATTRIBUTES DLLEXPORT :: TEST_REF
!DEC$ ATTRIBUTES ALIAS:'TEST_REF' :: TEST_REF
!DEC$ ATTRIBUTES VALUE :: N
IMPLICIT NONE
INTEGER*4 :: A,I,N
TYPE(VALUEREF) :: T(N)
A = 100
DO I=1,N
T(I)%A = A + I
END DO
END SUBROUTINE
END MODULE
和期望结果的C#
调用函数是:
and the C#
calling function that expects results is:
[StructLayout(LayoutKind.Sequential)]
public struct ValueRef
{
public int a;
}
[DllImport("mathlib.dll")]
static extern void TEST_REF(ValueRef[] t, int n);
void Main()
{
ValueRef[] T = new ValueRef[4];
for (int i = 0; i < T.Length; i++)
{
T[i].a = i;
}
Console.WriteLine("Initialize");
for (int i = 0; i < T.Length; i++)
{
Console.WriteLine(" A={0}", T[i].a);
}
Console.WriteLine("Call Fortran");
TEST_REF(T, T.Length);
for (int i = 0; i < T.Length; i++)
{
Console.WriteLine(" A={0}", T[i].a);
}
}
结果:
Initialize
A=0
A=1
A=2
A=3
Call Fortran
A=0
A=1
A=2
A=3
调试 FORTRAN 代码,我看到初始值从 C#
传递到 FORTRAN
就好了.值被新值覆盖,控制被传回 C#
,其中旧值仍包含在 ValueRef
实例中.
Debugging through the FORTRAN code, I see the initial values pass from C#
to FORTRAN
just fine. The the values get overridden with new values and control is passed back into C#
where the old values are still contained within the ValueRef
instances.
为什么我可以以类似的方式传递和返回 float
或 int
的数组,就好了.我可以传递和返回带有 ref
关键字的单数结构,我可以传递但不能返回和 struct
的数组?
Why is it that I can pass and return an array of float
, or int
in a similar fashion, just fine. and I can pass and return singular structures with ref
keyword, and I can pass but not return and array of struct
?
PS.我正在使用 Compaq Visual Fortran 6.5 &.NET 3.5
PS2.我感谢对此的任何评论/想法.我的项目已经完成了 95%,现在我遇到了这个问题.这个项目的重点是尽可能多地使用结构来减少传递给函数的参数#of并保留OOP设计的某些方面.
PS. I am using Compaq Visual Fortran 6.5 & .NET 3.5
PS2. I appreciate any comments/ideas on this. I am 95% done with my project, and now I run into this issue. The whole point of this project is to use structures as much as possible to reduce the #of arguments passed to functions and retain certain aspects of OOP design.
推荐答案
我过去使用指针而不是数组来完成此操作.我认为正在为 P/Invoke 调用复制您的结构:
I have done this in the past using a pointer, not an array. I think that your structures are being copied for the P/Invoke call:
[DllImport("mathlib.dll")]
static extern void TEST_REF(ValueRef* t, int n);
在调用该方法之前,您需要固定数组.
You will need to pin your array before calling the method.
fixed (ValueRef* pointer = t)
{
TEST_REF(pointer, n);
}
根据评论,解决方案是将外部声明为
Based on the comments the solution is to declare the external as
[DllImport("mathlib.dll")]
static extern void TEST_REF([Out] ValueRef[] t, int n);
这是一个 MSDN关于数组编组的参考,以及它们如何默认到[In]
.
Here is a MSDN reference on Marshaling of arrays, and how they default to [In]
.
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