delphi - FASM - 将字符串传递给 Delphi DLL

Question

我有一个使用以下代码在 Delphi XE2 中编码的 dll:

procedure xMain(MSG:String);export;
begin
  MessageBox(0,PWideChar(MSG),'Title',0);
end;

exports xMain;

现在，我在 FASM 应用程序中导入此函数，如下所示:

library  dllfile, "testdll.dll"

import   dllfile,\
         xMain,   "xMain"

利用是这样的:

section ".data" data readable writeable

szMSG     db "Message from FASM application!",0

section ".code" code readable executable

invoke    xMain,szMSG

但是生成的消息框显示的字符是这样的:

这是函数调用的确切结果。

我该如何解决这个问题？

Answer 1

这里有两个工作示例(使用适用于 Windows 的 FASM 1.70.03):

安西版,
动态链接库:

library testdll;

uses
  windows;

procedure xMain(MSG: PAnsiChar); export; stdcall;
begin
  MessageBoxA(0, PAnsiChar(MSG), 'Title', 0);
end;

exports xMain;

begin
end.

执行:

format PE CONSOLE 4.0
entry start

include 'win32a.inc'

section '.code' code readable executable
  start:
    invoke xMain, szMSG
    invoke ExitProcess, 0

section '.data' data readable writeable
    szMSG db 'Message from FASM application!', 0

section '.idata' import data readable writeable
  library kernel32, 'kernel32.dll',\
          dllfile, 'testdll.dll'

  include 'api\kernel32.inc'

  import dllfile,\
         xMain, 'xMain'

Unicode版本，
动态链接库:

library testdll;

uses
  windows;

procedure xMain(MSG: PChar); export; stdcall;
begin
  MessageBox(0, PChar(MSG), 'Title', 0);
end;

exports xMain;

begin
end.

执行:

format PE CONSOLE 4.0
entry start

include 'win32w.inc'

section '.code' code readable executable
  start:
    invoke xMain, szMSG
    invoke ExitProcess, 0

section '.data' data readable writeable
    szMSG du 'Message from FASM application!', 0

section '.idata' import data readable writeable
  library kernel32, 'kernel32.dll',\
          dllfile, 'testdll.dll'

  include 'api\kernel32.inc'

  import dllfile,\
         xMain, 'xMain'