从C DLL在Delphi中获取字符串返回值 [英] Get string return value from C DLL in Delphi

问题描述

我已经写在包含返回字符串的函数C遗留DLL，我需要从德尔福访问该功能。我对DLL的唯一信息是VB申报访问功能：

I have a legacy DLL written in C that contains a function that returns a string, and I need to access this function from Delphi. The only info I have about the DLL is the VB declare for accessing the function:

公开声明函数库DecryptStrSTRLIB（str作为字符串）作为字符串

Public Declare Function DecryptStr Lib "strlib" (Str As String) As String

我试过下面没有成功：

声明：

function DecryptStr(s: PChar): PChar; cdecl; external 'strlib.dll';

用法：

var
  p1, p2 : pchar;
begin
  GetMem( p1, 255 );
  StrPCopy( p2, 'some string to decrypt' );
  p1 := DecryptStr( p2 );
end;

这始终崩溃访问冲突该DLL。我不知所措。

This consistently crashes the DLL with an Access Violation. I'm at a loss.

有什么建议？

推荐答案

考虑重写你的测试code如下：

Consider rewriting your test code as follows:

var
  p1, p2 : pchar;
begin
  GetMem( p1, 255 ); // initialize
  GetMem( p2, 255 );
  StrPLCopy( p2, 'some string to decrypt', 255 ); // prevent buffer overrun
  StrPLCopy( p1, DecryptStr( p2 ), 255); // make a copy since dll will free its internal buffer
end;

如果要DecryptStr呼叫内仍然失败，那么阅读 http://support.microsoft.com/kb/187912小心。

If still fails within a call to DecryptStr, then read http://support.microsoft.com/kb/187912 carefully.

这篇关于从C DLL在Delphi中获取字符串返回值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！