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假设我有以下 Fortran 代码

subroutine COMPLEX_PASSING(r, i, c)
    !DEC$ ATTRIBUTES DLLEXPORT::COMPLEX_PASSING

    REAL*8 :: r, i
    COMPLEX*8 :: c

   c = cmplx((r * 2), (i * 2))

return
end

Fortran 代码是用

gfortran -c complex_passing.f90
gfortran -fPIC -shared -o complex_passing.dll complex_passing.o

我将如何在 C# 中调用此子例程？我尝试了以下代码：

using System;
using System.Runtime.InteropServices;

namespace FortranCalling {
    class Program {
        static void main(string[] args) {
            double real = 4;
            double imaginary = 10;
            COMPLEX c = new COMPLEX();

            complex_passing( ref real, ref imaginary, ref c);
            Console.WriteLine("Real: {0}\nImaginary: {1}", c.real, c.imaginary);
            Console.ReadLine();
        }

        [StructLayout(LayoutKind.Sequential)]
        struct COMPLEX {
            public double real;
            public double imaginary;
        }

        [DllImport("complex_passing.dll", EntryPoint = "complex_passing_", CallingConvention = CallingConvention.Cdecl)]
        static extern void complex_passing(ref double r, ref double i, ref COMPLEX c);
    }
}

收效甚微 - 我的 COMPLEX 结构似乎正在返回垃圾数据：

Real: 134217760.5
Imaginary: 0

当我期望实部是 8 而虚部是 20 时。

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1 回答 1

5

gfortran 将非标准COMPLEX*8视为 8 字节大小的复数，实部和虚部各 4 字节。相反，您需要 16 个字节的复数，实部和虚部各有 8 个字节 ( COMPLEX*16)，或者您应该相应地更改 C# 端。

在 gfortran 下可以看到以下效果：

complex*8 :: c8 = (8d0, 20d0)
complex*16 :: c16 = 0

c16%re = TRANSFER(c8,c16)

print*, c8, c16 

end

当然，你根本不应该使用complex*。使用 可以看到参数不匹配complex(kind=..)。

考虑以下“Fortran”源：

subroutine s(r, i, c)
  real(kind(0d0)) :: r, i
  complex(kind(0e0)) :: c
  c = cmplx((r*2),(i*2))
end subroutine s

interface ! Interface block required to lie to some versions of gfortran 
subroutine s(r, i, c)
  real(kind(0d0)) :: r, i
  complex(kind(0d0)) :: c
end subroutine s
end interface

complex(kind(0d0)) c
call s(4d0, 10d0, c)
print*, c%re

end

并将其与 Fortran 源代码进行比较：

subroutine s(r, i, c)
  real(kind(0d0)) :: r, i
  complex(kind(0d0)) :: c
  c = cmplx((r*2),(i*2))
end subroutine s

complex(kind(0d0)) c
call s(4d0, 10d0, c)
print*, c%re

end

此外，除了使用kind(0d0)等之外，还有各种 C 互操作性常量和iso_fortran_env.

于 2021-03-12T19:27:12.320 回答