Question

Why does this code get an access error on the Result := Buffer line in D2010, but not D7?

Something, I’d guess, involving UniCode, but the compiler doesn’t generate any warnings.

Any suggestions on an elegant workaround?

Edit: Ouch: the GetTempPath call is trashing the stack as evidenced by the fact that Extension is empty after the GetTempPath line, but not before… Yikes.

    function GetTempPathAndFileName( const Extension: string):  string;
    var
      Buffer: array[0..MAX_PATH] of Char;
    begin
      repeat
        GetTempPath(SizeOf(Buffer) - 1, Buffer);
        GetTempFileName(Buffer, '~', 0, Buffer);
        Result := Buffer;    // <--- crashes on this line,
        Result := ChangeFileExt(Result, Extension);
      until not FileExists(Result);
    end; { GetTempPathAndFileName }

Answer 1

GetTempPath is expecting the number of chars in the buffer for its first argument, not the size in bytes. Change SizeOf to Length and it will work.