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Asked: 2026-06-06T16:25:24+00:00

I have a DLL, written in XE2 that takes a PChar as a parameter

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I have a DLL, written in XE2 that takes a PChar as a parameter (therefore being a unicode string). I was hoping to write an application in Delphi 2006 that calls this DLL. Is this possible, how do I pass in the PChar parameter? If I was doing it in Delphi XE2 I would simply do:

tmpString := 'hello';
DLL_Call(PChar(tmpString));

I have tried defining my tmpString as a WideString in Delphi 2006, but I believe a WideString and an XE2 Unicode string differ considerably?

Is there a way I can pass the string correctly to the DLL? I am in control of the DLL source code so I could obviously change the function definition to PAnsiChar but I’d prefer not to do this, I was hoping for a solution from the Delphi 2006 side if possible.

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1 Answer

  1. Editorial Team

    You need to declare the function as receiving a PWideChar. And then use WideString to hold the payload.

    function DLL_Call(S: PWideChar); stdcall; external 'mylib.dll';

......
var
  tmpString: WideString;
......
tmpString := 'hello';
DLL_Call(PWideChar(tmpString));

    Remember that PChar is an alias. In pre-Unicode Delphi it is an alias to PAnsiChar. In Unicode Delphi it is an alias to PWideChar. Pre-Unicode Delphi is perfectly capable of calling any Unicode APIs, but must use PWideChar explicitly.

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