Question

尝试将字符发送到DLL时，似乎不正确（显示在“result_20170207”中）。下面是关于DLL的代码：

subroutine char_1( pfilename )
!DEC$ ATTRIBUTES stdcall,DLLEXPORT::char_1
!DEC$ ATTRIBUTES ALIAS:"char_1"::char_1
!DEC$ ATTRIBUTES reference :: pfilename

character(len=512)::pfilename
!integer::i     !(about ERROR TWO )
write(*,*)trim(pfilename)
!read(*,*)i     !(about ERROR TWO )
open(unit=18,file="result_20170207",status='replace',action='write')
  write(18,*)"This is dll"
  write(18,*)trim(pfilename)
  write(18,*)"the third line"
close(18)
end subroutine

以下是vb6.0中的代码：

Private Declare Sub char_1 Lib "D:\try_vb\char_1\char_1_dll\char_1_dll\Debug\char_1_dll.dll" (ByVal char As String)

Private Sub Command1_Click()
  Dim char As String
  char = "c:/desktop/aaa.txt"
  Text1.Text = char
  Call char_1(char)
End Sub

Private Sub Command2_Click()
  End
End Sub

错误一：结果文件中发生的错误是： wrong result

我认为这是因为这个角色。为什么会发生这种情况？我该如何解决？谢谢！

错误二：顺便说一句，当我添加代码“read（，）i”时，会遇到另一个错误。如下所示： severe(39) 我添加的代码显示在注释掉的代码中：我对这两个问题感到困惑。

根据MarkJ的回答，我已经更改了我的DLL代码，如下所示（ERROR ONE;此处省略了“String_Functions module”中的代码）：

subroutine char_1( pfilename )
  !DEC$ ATTRIBUTES stdcall,DLLEXPORT::char_1
  !DEC$ ATTRIBUTES ALIAS:"char_1"::char_1
  !DEC$ ATTRIBUTES reference :: pfilename

  use String_Functions     !--------here--------!

  character(len=512)::pfilename
  character(len=512)::filename
  integer::ii      
  ii=Clen(pfilename)      !--------here--------!
  filename=Ctrim(pfilename)     !--------here--------!
  open(unit=18,file="result_20170207",status='replace',action='write')
    write(18,*)"This is dll"
    write(18,*)filename(1:ii)      !--------here--------!
    write(18,*)"the third line"
  close(18)

end subroutine

Answer 1

关于您的错误（1）VB6是sending a null-terminated string。该字符串包含ASCII零字符，表示字符串的结尾。 Fortran TRIM不足以删除此角色。试试下面的CTRIM例程。

! ------------------------
PURE INTEGER FUNCTION Clen_trim(s) ! returns same result as LEN_TRIM unless:
CHARACTER(*),INTENT(IN) :: s       ! last char non-blank is null, if true:
INTEGER :: i                       ! then len of C string is returned, note:
                                   ! Ctrim is only user of this function
i = INDEX(s, CHAR(0)) 
IF ( i == 0 ) i = LEN_TRIM(s)
Clen_trim = i

END FUNCTION Clen_trim

! ----------------
FUNCTION Ctrim(s1)  RESULT(s2)     ! returns same result as TRIM unless:
CHARACTER(*),INTENT(IN)  :: s1     ! last non-blank char is null in which
CHARACTER(Clen_trim(s1)) :: s2     ! case trailing blanks prior to null
s2 = s1                            ! are output
END FUNCTION Ctrim

vb6中的Fortran DLL：关于“字符”和“读句子”的错误

1 个答案: