debugging - 从 VB6.0 调用时，DLL 中的 Fortran `read(*,*)` 会导致 "run time error(39)"

Question

VB6.0中的代码是:

Private Declare Sub suba Lib "D:\try_vb\c_dll\Dll1\Dll1\Debug\Dll1.dll" (ByRef a As Single, ByRef b As Single, ByRef c As Single)
Private Sub Command1_Click()
    Dim a As Single
    Dim b As Single
    Dim c As Single
    a = 10#
    b = 2#
    Call suba(a, b, c)
    Text1.Text = c
End Sub

Fortran DLL 中的代码是:

subroutine suba(a,b,c)
!DEC$ ATTRIBUTES stdcall,DLLEXPORT ::suba
!DEC$ ATTRIBUTES ALIAS:"suba"::suba
!DEC$ ATTRIBUTES reference :: a,b,c
    implicit none
    real::a
    real::b
    real::c
    real::aaa

    c=a+b
    read(*,*)aaa       !This sentence seems wrong
end subroutine

如果read(*,*)aaa行不存在，程序可以返回正确答案c=12，如下所示:

但是当read(*,*)aaa存在时，就会发生错误，即

forrtl:severe(39):error during read,unit -4,file CONIN$

我应该做什么？

Answer 1

这非常简单 - Fortran 代码正在尝试从控制台读取，而 VB 应用程序中没有。一般来说，您应该使用一种语言完成所有 I/O。您可以在 Fortran 中执行 READ 之前调用 Windows API 例程 AllocConsole 创建一个控制台，但这对于具有图形界面的 VB 应用程序来说似乎很愚蠢。