How convert null-terminated string to an AnsiString?

Question

I have some code that compiles fine with D7 but fails with D2010. Obviously it is an Unicode issue:

The compile error is: E2251 Ambiguous overloaded call to 'StrPas'

Here is the whole procedure:

procedure GetVersionInfo;
type
  PLangCharSetInfo = ^TLangCharSetInfo;
  TLangCharSetInfo = record
    Lang: Word;
    CharSet: Word;
  end;
var
  FileName: array [0..260] of Char;
  SubBlock: array [0..255] of Char;
  VerHandle: Cardinal;
  Size: Word;
  Buffer: Pointer;
  Data: Pointer;
  DataLen: LongWord;
  LangCharSetInfo: PLangCharSetInfo;
  LangCharSetString: string;
begin
  LabelComments.Caption := 'No version information for this program is available!';
  {Get size and allocate buffer for VerInfo}
  if GetModuleFileName(hInstance, FileName, SizeOf(FileName)) > 0 then
  begin
    Size := GetFileVersionInfoSize(FileName, VerHandle);
    if Size > 0 then
    begin
      GetMem(Buffer, Size);
      try
        if GetFileVersionInfo(FileName, VerHandle, Size, Buffer) then
        begin
          {Query first language and that language blocks version info}
          if VerQueryValue(Buffer, '\VarFileInfo\Translation', Pointer(LangCharSetInfo), DataLen) then
          begin
            LangCharSetString := IntToHex(LangCharSetInfo^.Lang, 4) +
                                 IntToHex(LangCharSetInfo^.CharSet, 4);
            if VerQueryValue(Buffer, StrPCopy(SubBlock, '\StringFileInfo\' + LangCharSetString + '\ProductName'), Data, DataLen) then
            begin
              LabelProductName.Caption := StrPas(Data);
              Caption := LabelProductName.Caption;
            end;
            if VerQueryValue(Buffer, StrPCopy(SubBlock, '\StringFileInfo\' + LangCharSetString + '\FileVersion'), Data, DataLen) then
              LabelVersion.Caption := StrPas(Data);
            if VerQueryValue(Buffer, StrPCopy(SubBlock, '\StringFileInfo\' + LangCharSetString + '\LegalCopyright'), Data, DataLen) then
              LabelCopyright.Caption := StrPas(Data);
            if VerQueryValue(Buffer, StrPCopy(SubBlock, '\StringFileInfo\' + LangCharSetString + '\Comments'), Data, DataLen) then
              LabelComments.Caption := StrPas(Data);
          end;
        end;
      finally
        FreeMem(Buffer, Size);
      end;
    end
  end;
end;

The doc for StrPas says

function StrPas(const Str: PAnsiChar): AnsiString; overload;

This function is provided fasor backwards compatibility only. To convert a null-terminated string to an AnsiString or native Delphi language string, use a typecast or an signment.

So the question is should I remove all calls to StrPas ? The only way I make this to compile is to do a hardcast to PAnsi char like:

LabelProductName.Caption := StrPas(PAnsiChar(Data));

Answer 1

StrPas has not been required since Delphi 1, since they changed the Delphi compiler to convert the string correctly without a function call. See: http://coding.derkeiler.com/Archive/Delphi/borland.public.delphi.language.objectpascal/2004-01/1793.html

So just assign it, as follows:

LabelProductName.Caption := PAnsiChar(Data);

And yes, you should remove all calls to StrPas. It can't help and can only get you in trouble in D2010.