I use Beyond Compare (version 3.1.10) to compare different versions of Delphi Form Files, but I don&#39;t want to see differences concerning ExplicitTop, ExplicitLeft, ExplicitHeight and ExplicitWidth. 

Details:
These lines will always begin with a number of whitespace characters, then &quot;ExplicitXXX = &quot; and a number. Older versions of Delphi didn&#39;t have these lines, so I want to ignore differences where these lines are added to the newest version, and I also want to ignore differences where the number has changed.

Does anyone know how to do this?

Edit:
Duplicate (more or less) of:

https://stackoverflow.com/questions/3652301/how-do-i-configure-beyondcompare-to-ignore-scm-replaced-text-in-comments



How do I make Beyond Compare ignore certain differences while comparing versions of Delphi Form Files

I am getting an error after installing Delphi 2007 (Edit: This problem occurs in all Delphi versions from 2006 to 2010) that I can not figure out and have never seen before.  After restarting I can launch the program without any problems, but if I were to close out of the program and start again it will give me the following error: 

**&quot;Cannot create file C:\Users\Admin\AppData\Local\Temp\EditorLineEnds.ttr&quot;.  The process cannont access the file because it is being use by another process.&quot;**


&quot;System&quot; has a handle on this file that cannot be cleared unless I reboot. I can also correct the problem by renaming the file before I launch the program. 

I have tried reinstalling the program with no luck. 

Version installed: CodeGear™ Delphi&#174; 2007 for Win32&#174; R2 Version 11.0.2902.10471. 
Operation System: Windows 7 Pro 64bit

**Update 08/14 13:35 EDT**
Tried the following solutions, but still having the same file lock issue: 

 1. Renamed Temp Directory to a directory I know had full security rights.  Files would be created in this directory when launching Delphi, but EditorLineEnds.ttr  would still get locked by SYSTEM and prevent me from relaunching.
 2. Uninstalled the following security updates KB2982791 and KB2976897, but this did not solve the problem.  I have suppressed windows updates for now and will try uninstalling all security patches for 8/13.  
 3. Uninstalled Delphi completely and re-installed.  Problem still occurs after re-installing everything. 

I will try reinstalling Windows from scratch and install Delphi before Windows 
updates to see if updates are truly the cause.  My workaround for now is just renaming EditorLineEnds.ttr before launch Delphi.

Delphi 2006-2010 error: &quot;Cannot create file C:\Users\Admin\AppData\Local\Temp\EditorLineEnds.ttr&quot;

I recently upgraded from Delphi 4 to Delphi 2009. With Delphi 4 I had been using [GpProfile by Primoz Gabrijelcic][1] as a profiler and [Memory Sleuth by Turbo Power][2] for memory analysis and leak debugging. Both worked well for me. But I now need new tools that will work with Delphi 2009. 

The leader in Profiling/Analysis tools for Delphi by a wide margin is obviously [AQTime by AutomatedQA][3]. They recently even gobbled up [Memproof by Atanas Soyanov][4], which I understood was an excellent and free memory analysis tool, and incorporated its functionality into AQTime. But AQTime is very expensive for an individual programmer. It actually costs more than the upgrade to Delphi 2009 cost!

So my question is: Are there other less expensive options to do profiling and memory analysis in current versions of Delphi that you are happy with and recommend, or should I bite the bullet and pay the big bucks for AQTime?

------------------------------------
Addenum: It seems the early answerers are indicating that the FastMM manager already included in Delphi is very good for finding memory leaks.

So then, are there any good alternatives for source code profiling?  

One I&#39;m curious about is [ProDelphi by Michael Adolph][5] which is less than one sixth the cost of AQTime. Do you use it? Is AQTime worth paying six times as much?

------------------------------------
Addenum 2: I downloaded trial versions of both AQTime and ProDelphi.

AQTime was a bit overwhelming and a little confusing at first. It took a few hours to find some of the tricks needed to hook it up. 

ProDelphi was very much like the GpProfile that I was used to. But its windows are cluttered and confusing and it&#39;s not quite as nice as GpProfile.

To me the big differences seem to be:

1. ProDelphi changes your code. AQTime does not. Changing code may corrupt your data if something goes wrong, but my experience with GpProfile was that it never happened to me. Plus one for AQTime.

2. ProDelphi requires you turn optimization off. But what you want to profile is your program with optimization on, the way it will be run. Plus one for AQTime.

3. ProDelphi only can profile down to the function or procedure. AQTime can go down to individual lines. Plus 2 for AQTime.

4. ProDelphi has a free version that will profile 20 routines, and its pro version costs less than $100 USD. AQTime is $600 USD.  Plus 4 for ProDelphi.

The score is now 4-4. What do you think?

------------------------------------
Addenum 3: Primoz Gabrijelcic is planning to get GpProfile working again. See his comments on some of the responses below. He on StackOverflow as [Gabr][6].

------------------------------------
Addenum 4: It seems like there may be a profiler solution after all. See [Andre&#39;s open source asmprofiler, described below][7].


  [1]: http://web.archive.org/web/20001205122400/http&amp;#58;//www.eccentrica.org/gabr/gpprofile/gpprofile.htm
  [2]: http://web.archive.org/web/20031204135824/http&amp;#58;//www.turbopower.com/products/sleuth/
  [3]: http://www.automatedqa.com/products/aqtime/index.asp
  [4]: http://www.scip.be/index.php?Page=ArticlesDelphi07&amp;Lang=EN
  [5]: http://www.prodelphi.de/indexpd.htm
  [6]: https://stackoverflow.com/users/4997/gabr
  [7]: https://stackoverflow.com/questions/291631/profiler-and-memory-analysis-tools-for-delphi/672554#672554

Profiler and Memory Analysis Tools for Delphi

I&#39;m coming from a background of using [MSC* MidiSequencer][1] for a Delphi XE2 project and have been playing with DelphiASIOVST this weekend on the off chance the MIDI may be stable enough to use as my core MIDI engine while also allowing me to support VST plug ins. I pulled the D16 trunk off the SVN and compiled effortlessly after a few path tweaks. 

I understand a great deal of what I&#39;m seeing but I&#39;m wondering if others have experienced issues with MIDI file playback in the the MiniHost example application. Specifically with a one track melodic performance it sounds like notes are getting skipped and/or playing back a bit later over other notes that are playing as they should. Basically it&#39;s just hit or miss if a note is even played at all.

I have numerous pro sequencers on my machine and the MIDI files are fine there. they also support VST with little to no problems. I also know the MIDI lowest level file format and know the file structure is sound.

Can the TMidiFile play direct to the standard MIDI synth in the computer? I&#39;m trying to rule out VST issues by getting a direct pipeline to the built in synth. Barring that, anyone seen these issues or know of some more/better examples of MIDI file to VST using the component set?

  [1]: http://sourceforge.net/projects/midisequencer/


Midi Timing Issues with Delphi ASIO VST and MiniHost

I know how to get the System memory use using GlobalMemoryStatusEx, but that tells me the what the entire OS is using.

I really want my program to report how much memory it alone has allocated and is using. 

Is there any way within my Delphi 2009 program to call either a Windows function or maybe some FastMM function to find out the memory that has been allocated by my program alone?

---

Revisiting my question, I have now changed my accepted answer to the GetMemoryManagerState answer by @apenwarr. It produced identical results to the GetHeapStatus function (now deprecated) that I used to use, whereas GetProcessMemoryInfo.WorkingSetSize gave a very different result. 

How to get the Memory Used by a Delphi Program

I don&#39;t know which of those three methods suits me most. They all work for me. Does anyone know the difference between Refresh, Update and Repaint?

What&#39;s the difference between Refresh, Update and Repaint?

**Update:** XE2 Update 2 fixes the bug described below.

The program below, cutdown from the real program, fails with an exception in XE2. This is a regression from 2010. I don&#39;t have XE to test on but I&#39;d expect that the program works fine on XE (thanks to Primož for confirming that the code runs fine on XE).

    program COMbug;

    {$APPTYPE CONSOLE}

    uses
      SysUtils, Variants, Windows, Excel2000;

    var
      Excel: TExcelApplication;
      Book: ExcelWorkbook;
      Sheet: ExcelWorksheet;
      UsedRange: ExcelRange;
      Row, Col: Integer;
      v: Variant;

    begin
      Excel := TExcelApplication.Create(nil);
      try
        Excel.Visible[LOCALE_USER_DEFAULT] := True;
        Book := Excel.Workbooks.Add(EmptyParam, LOCALE_USER_DEFAULT) as ExcelWorkbook;
        Sheet := Book.Worksheets.Add(EmptyParam, EmptyParam, 1, EmptyParam, LOCALE_USER_DEFAULT) as ExcelWorksheet;

        Sheet.Cells.Item[1,1].Value := 1.0;
        Sheet.Cells.Item[2,2].Value := 1.0;
        UsedRange := Sheet.UsedRange[LOCALE_USER_DEFAULT] as ExcelRange;
        for Row := 1 to UsedRange.Rows.Count do begin
          for Col := 1 to UsedRange.Columns.Count do begin
            v := UsedRange.Item[Row, Col].Value;
          end;
        end;
      finally
        Excel.Free;
      end;
    end.

In XE2 32 bit the error is:

&gt; Project COMbug.exe raised exception class $C000001D with message &#39;system exception (code 0xc000001d) at 0x00dd6f3e&#39;.

The error occurs on the second execution of `UsedRange.Columns`.

In XE2 64 bit the error is:

&gt; Project COMbug.exe raised exception class $C0000005 with message &#39;c0000005 ACCESS_VIOLATION&#39;

Again, I think that the error occurs on the second execution of `UsedRange.Columns`, but the 64 bit debugger steps through the code in a slightly weird way so I&#39;m not 100% sure of that.

I have submitted a [QC report][1] for the issue.

I looks very much to me as though something in the Delphi COM/automation/interface stack is comprehensively broken. This is a complete show-stopper for my XE2 adoption.

Does anyone have any experience of this problem? Does anyone have any tips and advice as to how I might attempt to work around the problem? Debugging what&#39;s really going on here is outside my area of expertise.


  [1]: http://qc.embarcadero.com/wc/qcmain.aspx?d=100414

Is COM broken in XE2, and how might I work around it?

With the help of `Sertac Akyuz`, it seems the direct reason is related to the charset of `\bullet`: In my localized Windows, the `\bullet` input by typing Alt(0149) always gets `\fcharset134`, and attempts to change its font through `EM_SETCHARFORMAT` always fail (well, the color, size, style can indeed be changed but not font family name).

The simplest workaround is therefore to first reset the charset and then change the font. 

Note: RichEdit **(version &gt;= 4.1)** should be used! 

Note: RichEdit versions can be found at MSDN&#39;s [ About Rich Edit Controls][1], Murray Sargent&#39;s MSDN Blog [RichEdit versions][2] and [RichEdit Versions Update to 7.0][3]. The latter pages mentioned RichEdit versions higher than 4.1. As a test, I copied the RICHED20.DLL shiped with Office 2010 together with the application to Windows 2000, and everything works like a charm!

    procedure TMainForm.ButtonFontClick(Sender: TObject);
    var
      format: TCharFormat2;
    begin
      if dlgFontCdxTxt.Execute then
      begin
        FillChar(format, sizeof(format), 0);
        format.cbSize:= Sizeof(format);
        format.dwMask:= CFM_CHARSET;
        format.bCharSet := 1; // or 0;
        redtTextBlock.Perform(EM_SETCHARFORMAT, SCF_SELECTION, Integer(@format));
    
        FillChar(format, sizeof(format), 0);
        format.cbSize:= Sizeof(format);
        format.dwMask:= CFM_FACE;
        StrPLCopy(format.szFaceName, dlgFontCdxTxt.Font.Name, High(format.szFaceName));
        redtTextBlock.Perform(EM_SETCHARFORMAT, SCF_SELECTION, Integer(@format));
      end;
      redtTextBlock.SetFocus;
    end;

==================================================

According to [Wikipedia][4], `WordPad` used Microsoft&#39;s `RichEdit` control, versions 1.0, 2.0 and 3.0 in Windows 95, 98 and Windows 2000, respectively. In Windows XP SP1 and later, WordPad uses RichEdit 4.1, including Windows 7. 

Say a rtf document, being edited in WordPad, contains a non-text character Alt(0149), `the bullet dot •`. (Or U+2022)

In Windows 2000 SP4 or XP SP2, the font of that bullet dot can only take the default font of WordPad. That is to say, one cannot change font for that bullet dot interactively in WordPad. 

However, in Windows 7 SP1, one could change its font by `first changing to &quot;Arial Unicode MS&quot;`, and then to any desired font unlimited times. 

![Wordpad_1][5]
![WordPad_2][6]
![WordPad_3][7]

Furthermore, WordPad document created using WordPad in Windows 7 that contains different fonts of the dot can be opened and viewed correctly in WordPad in Windows 2000 or XP.

The TRichEdit (Delphi XE, Windows 7) can also open and view the WordPad document created using WordPad in Windows 7 correctly by `TRichEdit.Lines.LoadFromFile`.

![TRichEdit_1][8]

Interactively, the TRichEdit (Delphi XE, Windows 7) allows `the bullet dot`&#39;s font to be changed to &quot;Arial Unicode MS&quot;. However, one cannot go further to change to other fonts interactively in TRichEdit.
![TRichEdit_2][9]
![TRichEdit_3][10]
![TRichEdit_4][11]

I am therefore wondering (1) the reason of the different behavior of WordPad in Windows 7, and (2) whether it is possible to make TRichEdit behave alike?

PS: One may need type Alt(0149) several times to get the dot in WordPad. Typing 2022 and Alt+x always works, as suggested [here][12]. 

PS: One need to &quot;activate&quot; the fonts in WordPad as mentioned in the answer of [Why TFontDialog gives less fonts than Screen.Fonts?][13]

PS: One can always change the dot to different fonts in Word.

###sample.rtf (paste into a plain text file and then change the extension to rtf to use)
    {\rtf1\ansi\ansicpg936\deff0\deflang1033\deflangfe2052{\fonttbl{\f0\fswiss\fprq2\fcharset134 Arial Unicode MS;}{\f1\fnil\fcharset0 Arial Unicode MS;}{\f2\froman\fprq2\fcharset0 Times New Roman;}{\f3\fscript\fprq2\fcharset0 Comic Sans MS;}{\f4\fnil\fcharset0 Comic Sans MS;}{\f5\fmodern\fprq1\fcharset0 Consolas;}{\f6\fnil\fcharset0 Consolas;}{\f7\fmodern\fprq1\fcharset0 Lucida Console;}{\f8\fnil\fcharset0 Lucida Console;}{\f9\froman\fprq2\fcharset2 Symbol;}{\f10\froman\fprq2\fcharset0 Symbol;}{\f11\fnil\fcharset134 \&#39;cb\&#39;ce\&#39;cc\&#39;e5;}}
    {\*\generator Msftedit 5.41.21.2510;}\viewkind4\uc1\pard\nowidctlpar\sa200\sl276\slmult1\lang2052\f0\fs22 Arial sample text \lang1033\f1\bullet\f2\par
    \b\f3 Comic sample text \f4\bullet\f2\par
    \b0\f5 Consolas sample text \f6\bullet\f2\par
    \f7 Lucida sample text \f8\bullet\f2\par
    \pard\nowidctlpar\qj\lang2052\f9 symbl sample text \lang1033\f10\u149?\kerning2\fs21\par
    \pard\sa200\sl276\slmult1\lang2052\kerning0\f11\fs22\par
    }

###uMainForm.dfm to view the format of the lines of TRichEdit

    object MainForm: TMainForm
      Left = 0
      Top = 0
      Caption = &#39;MainForm&#39;
      ClientHeight = 362
      ClientWidth = 637
      Color = clBtnFace
      Font.Charset = DEFAULT_CHARSET
      Font.Color = clWindowText
      Font.Height = -11
      Font.Name = &#39;Tahoma&#39;
      Font.Style = []
      OldCreateOrder = False
      OnCreate = FormCreate
      PixelsPerInch = 96
      TextHeight = 13
      object pnlBtn: TPanel
        Left = 0
        Top = 0
        Width = 637
        Height = 57
        Align = alTop
        Caption = &#39;pnlBtn&#39;
        TabOrder = 0
        object Button1: TButton
          Left = 240
          Top = 14
          Width = 137
          Height = 31
          Caption = &#39;Analyze Rich Edit&#39;
          TabOrder = 0
          OnClick = Button1Click
        end
      end
      object pnlClient: TPanel
        Left = 0
        Top = 57
        Width = 637
        Height = 305
        Align = alClient
        Caption = &#39;pnlClient&#39;
        TabOrder = 1
        object redtTextBlock: TRichEdit
          Left = 1
          Top = 1
          Width = 225
          Height = 303
          Align = alLeft
          Font.Charset = GB2312_CHARSET
          Font.Color = clWindowText
          Font.Height = -11
          Font.Name = &#39;Tahoma&#39;
          Font.Style = []
          Lines.Strings = (
            &#39;redt1&#39;)
          ParentFont = False
          TabOrder = 0
        end
        object mmo1: TMemo
          Left = 226
          Top = 1
          Width = 410
          Height = 303
          Align = alClient
          Lines.Strings = (
            &#39;mmo1&#39;)
          TabOrder = 1
        end
      end
      object Button2: TButton
        Left = 36
        Top = 14
        Width = 171
        Height = 31
        Caption = &#39;Font...&#39;
        TabOrder = 2
        OnClick = Button2Click
      end
      object dlgFontCdxTxt: TFontDialog
        Font.Charset = DEFAULT_CHARSET
        Font.Color = clWindowText
        Font.Height = -11
        Font.Name = &#39;Tahoma&#39;
        Font.Style = []
        Left = 480
        Top = 16
      end
    end
    
###uMainForm.pas to view the format of the lines of TRichEdit

    unit uMainForm;
    
    interface
    
    uses
      Contnrs,
      Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
      Dialogs, StdCtrls, ComCtrls, ExtCtrls;
    
    type
    
      TCdxmlStyle = class
      public
        FontName: string;
        Str: string;
      end;
    
      TCdxmlText = class
      public
        Styles: TObjectList;
        constructor Create;
      end;
    
      TMainForm = class(TForm)
        redtTextBlock: TRichEdit;
        mmo1: TMemo;
        pnlBtn: TPanel;
        pnlClient: TPanel;
        Button1: TButton;
        Button2: TButton;
        dlgFontCdxTxt: TFontDialog;
        procedure Button1Click(Sender: TObject);
        procedure Button2Click(Sender: TObject);
        procedure FormCreate(Sender: TObject);
      private
        { Private declarations }
        procedure TestLoadFromFile;
        procedure AnalyzeRichEdit;
      public
        { Public declarations }
      end;
    
    var
      MainForm: TMainForm;
    
    implementation
    
    {$R *.dfm}
    
    uses
      RichEdit, StrUtils;
    
    { TCdxmlText }
    
    constructor TCdxmlText.Create;
    begin
      Styles := TObjectList.Create;
    end;
    
    var
      l_HiddenRichEdit: TRichEdit;
    
    { TMainForm }
    
    procedure TMainForm.FormCreate(Sender: TObject);
    begin
      TestLoadFromFile;
      AnalyzeRichEdit;
    end;
    
    procedure TMainForm.Button2Click(Sender: TObject);
    var
      format: TCharFormat2;
    begin
      if dlgFontCdxTxt.Execute then
      begin
        FillChar(format, sizeof(format), 0);
        format.cbSize:= Sizeof(format);
        format.dwMask:= CFM_FACE;
    
        StrPLCopy(format.szFaceName, dlgFontCdxTxt.Font.Name, High(format.szFaceName));
    
        redtTextBlock.Perform(EM_SETCHARFORMAT, SCF_SELECTION, Integer(@format));
      end;
      redtTextBlock.SetFocus;
    end;
    
    procedure TMainForm.Button1Click(Sender: TObject);
    begin
      AnalyzeRichEdit;
    end;
    
    procedure TMainForm.TestLoadFromFile;
    begin
      redtTextBlock.Clear;
    
      redtTextBlock.Lines.LoadFromFile(&#39;sample.rtf&#39;);
    end;
    
    procedure TMainForm.AnalyzeRichEdit;
    var
      l_MemStream: TMemoryStream;
      l_Format: TCharFormat2;
    
      I, J: Integer;
      l_CdxmlStyle, l_CdxmlStyleWorker: TCdxmlStyle;
      l_StyleFont: string;
    
      l_CdxmlText: TCdxmlText;
    begin
      l_CdxmlStyle := nil;
      l_CdxmlStyleWorker := nil;
    
      mmo1.Clear;
    
      l_MemStream := TMemoryStream.Create;
      redtTextBlock.Lines.SaveToStream(l_MemStream);
      l_MemStream.Seek(0, soFromBeginning);
      l_HiddenRichEdit.Lines.LoadFromStream(l_MemStream);
    
      l_CdxmlText := TCdxmlText.Create;
      for I := 0 to Length(TrimRight(l_HiddenRichEdit.Text)) - 1 do
      begin
        l_CdxmlStyleWorker := TCdxmlStyle.Create;
    
        FillChar(l_Format, sizeof(l_Format), 0);
        l_Format.cbSize:= Sizeof(l_Format);
        l_Format.dwMask:= CFM_FACE;
    
        l_HiddenRichEdit.SelStart := I;
        l_HiddenRichEdit.SelLength := 1;
        l_HiddenRichEdit.Perform(EM_GETCHARFORMAT, SCF_SELECTION, Integer(@l_Format));
    
        l_CdxmlStyleWorker.FontName := l_Format.szFaceName;
    
        l_CdxmlStyleWorker.Str := AnsiReplaceStr(l_HiddenRichEdit.SelText, #13, #13#10);
    
        if l_CdxmlStyle = nil then
        begin
          l_CdxmlText.Styles.Add(l_CdxmlStyleWorker);
          l_CdxmlStyle := l_CdxmlStyleWorker;
        end
        else if (l_CdxmlStyleWorker.FontName  &lt;&gt; l_CdxmlStyle.FontName ) then
        begin
          l_CdxmlText.Styles.Add(l_CdxmlStyleWorker);
          l_CdxmlStyle := l_CdxmlStyleWorker;
        end
        else
        begin
          l_CdxmlStyle.Str := l_CdxmlStyle.Str + l_CdxmlStyleWorker.Str;
        end;
      end;
    
      for I := 0 to l_CdxmlText.Styles.Count - 1 do
      begin
        l_CdxmlStyle := TCdxmlStyle(l_CdxmlText.Styles[I]);
        mmo1.Lines.Add(l_CdxmlStyle.Str + &#39;:&#39; + l_CdxmlStyle.FontName);
      end;
    end;
    
    initialization
    
      l_HiddenRichEdit := TRichEdit.CreateParented(HWND_MESSAGE);
    
    end.


  [1]: http://msdn.microsoft.com/en-us/library/windows/desktop/bb787873%28v=vs.85%29.aspx
  [2]: http://blogs.msdn.com/b/murrays/archive/2011/10/17/824003.aspx
  [3]: http://blogs.msdn.com/b/murrays/archive/2009/09/05/richedit-versions-update-to-7-0.aspx
  [4]: http://en.wikipedia.org/wiki/WordPad
  [5]: http://i.stack.imgur.com/hDokb.png
  [6]: http://i.stack.imgur.com/xQAEf.png
  [7]: http://i.stack.imgur.com/5oJQo.png
  [8]: http://i.stack.imgur.com/JY51Z.png
  [9]: http://i.stack.imgur.com/xxsg2.png
  [10]: http://i.stack.imgur.com/7NBoB.png
  [11]: http://i.stack.imgur.com/VDMkX.png
  [12]: http://us.generation-nt.com/answer/alt-plusxxx-keystroke-dont-make-through-my-richedit-control-help-26070432.html?page=2
  [13]: https://stackoverflow.com/questions/11300277/why-tfontdialog-gives-less-fonts-than-screen-fonts

How to make TRichEdit behave like WordPad on Windows 7 when changing font for certain non-text characters?

What is `TApplication.Handle`? 

 - Where does it come from? 
 - Why does it exist? 
 - And most importantly: why do all forms have it as their parent window handle?

The Delphi help says:

&gt; **TApplication.Handle**
&gt; 
&gt; Provides access to the window handle
&gt; of the main form (window) of the
&gt; application.
&gt; 
&gt;     property Handle: HWND;
&gt; 
&gt; **Description**
&gt; 
&gt; Use Handle when calling Windows API
&gt; functions that require a parent window
&gt; handle. For example, a DLL that
&gt; displays its own top-level pop-up
&gt; windows needs a parent window to
&gt; display its windows in the
&gt; application. Using the Handle property
&gt; makes such windows part of the
&gt; application, so that they are
&gt; minimized, restored, enabled and
&gt; disabled with the application.

If I focus on the words &quot;*the window handle of the main form of the application*&quot;, and I take that to mean *the window handle of the main form of the application*, then I can compare: 

 - &quot;the window handle of the main form of the application&quot;, with
 - the window handle of the `MainForm` of the `Application`

but they are not the same:

    Application.MainForm.Handle: 11473728
    Application.Handle: 11079574

So what is `Application.Handle`? 

 - Where does it come from? 
 - What Windows&amp;reg; window handle is it?
 - If it **is** the Windows&amp;reg; window handle of the `Application`&#39;s `MainForm`, then why don&#39;t they match?
 - If it&#39;s **not** the window handle of the `Application`&#39;s `MainForm`, then what is it?
 - More importantly: Why is it the ultimate &lt;strike&gt;parent&lt;/strike&gt; owner of every form?
 - And most important: Why does everything go haywire if i try to have a form be &lt;strike&gt;unparented&lt;/strike&gt; unowned (so i it can appear on the TaskBar), or try to use something like **IProgressDialog**?

Really what I&#39;m asking is: What is the design rationale that makes **Application.Handle** exist? If I can understand the why, the how should become obvious.

---

Understanding through a game of twenty questions:

In talking about the solution of making a window appear on the taskbar by making its owner `null`, [Peter Below in 2000 said][1]:

&gt; This can cause some problems with modal forms shown from 
&gt; secondary forms. 
&gt; 
&gt; If the user switches away from the app while a modal 
&gt; form is up, and then back to the form that showed it, the modal form may 
&gt; hide beneath the form. It is possible to deal with this by making sure 
&gt; the modal form is parented [sic; he meant owned] to the form that showed it (using 
&gt; `params.WndParent` as above) 
&gt; 
&gt; But this is not possible with the standard 
&gt; dialogs from the `Dialogs` unit and **exceptions**, which need more effort to 
&gt; get them to work right (basically handling `Application.OnActivate`, 
&gt; looking for modal forms parented to **Application** via `GetLastActivePopup`
&gt; and bringing them to the top of the Z-order via `SetWindowPos`). 

 - Why does a modal form end up stuck behind other forms?
 - What mechanism normally brings a modal form to the front, and why is it not functional here?
 - Windows&amp;reg; is responsible for showing windows stacked. What has gone wrong that Windows&amp;reg; isn&#39;t showing the right windows?

He also talked about using the new Windows extended style that forces a window to appear on the taskbar (when the normal rules of making it un-owned is insufficient, impractical, or undesirable), by adding the `WS_EX_APPWINDOW` extended style:

    procedure TForm2.CreateParams(var Params: TCreateParams); 
    begin 
       inherited CreateParams( params ); 

       Params.ExStyle := Params.ExStyle or WS_EX_APPWINDOW; 
    end; 

But then he cautions: 

&gt; If you click on a secondary forms taskbar button while another app is 
&gt; active this will still bring all the applications forms to front. If you 
&gt; do not want that there is option 

Who is bringing all the forms to the front when the form&#39;s owner is still `Application.Handle`. Is **Application** doing this? Why is it doing this? Rather than doing this, shouldn&#39;t it **not** be doing this? What is the downside of **not** doing this; I see the downside of **doing** it (system menu&#39;s don&#39;t work property, taskbar button thumbnails are inaccurate, Windows&amp;reg; shell cannot minimize windows.


----------

In another post dealing with the `Application`, [Mike Edenfield says that the parent window sends other window&#39;s their minimize, maximize and restore messages][2]:

&gt; This will add the taskbar button for your form, but there are a few other minor details to 
&gt; handle.  Most obviously, your form still receives minimize/maximize that get sent to the parent 
&gt; form (the main form of the application).  In order to avoid this, you can install a message 
&gt; handler for WM_SYSCOMMAND by adding a line such as: 

&gt;     procedure WMSysCommand(var Msg: TMessage); WM_SYSCOMMAND; 
&gt; 
&gt;     procedure TParentForm.WMSysCommand(var Msg: TMessage); 
&gt;     begin 
&gt;        if Msg.wParam = SC_MINIMIZE then 
&gt;        begin 
&gt;           // Send child windows message, don&#39;t 
&gt;           // send to windows with a taskbar button. 
&gt;        end; 
&gt;     end; 
&gt; 
&gt; Note that this handler goes in the **PARENT** form of the one you want to behave independently of &gt; the rest of the application, so as to avoid passing on the minimize message. You can add similar &gt; code for SC_MAXIMIZE, SC_RESTORE, etc.

How is it that minimize/maximize/restore messages for my Windows&amp;reg; windows are not going to my window? Is this because messages destined for a window are sent, by Windows&amp;reg; to the window&#39;s owner? And in this case all the forms in a Delphi application are &quot;owned&quot; by `Application`? Does that not mean that making the owner null:

    procedure TForm2.CreateParams(var Params: TCreateParams);
    begin
       inherited;
       Params.WndParent := 0; //NULL
    end;

will remove `Application` and it&#39;s window Handle from interfering with my form, and Windows should once again send *me* my minimize/maximize/restore messages?

---

Perhaps if we compared and contrasted now a &quot;normal&quot; Windows application does things, with how Borland initially designed Delphi applications to do things - with respect to this `Application` object and it&#39;s main loop. 

 - what solution was the `Application` object solving?
 - What change was made with later versions of Delphi so that these same issues don&#39;t exist? 
 - Did the change in later versions of Delphi not introduce other problems, that the initial Application design tried so hard to solve?
 - How can those newer applications still function without Application interfering with them?

Obviously Borland realized the flaw in their initial design. What was their initial design, what problem was it solving, what is the flaw, what was the re-design, and how does it solve the problem?

  [1]: http://groups.google.com/group/borland.public.delphi.objectpascal/msg/1754081cc34d3576
  [2]: http://www.delphi3000.com/articles/article_723.asp?SK=

Delphi: What is Application.Handle?

What is the basic difference between Free and FreeAndNil?

Is FreeAndNil = Free + Nil?

When should I use Free and when should I use FreeAndNil?

Which is preferable: Free or FreeAndNil?

Delphi has a $WARN compiler directive that allows one to selectively enable or disable specific warnings.  The Delphi 2009 help file describes the syntax:

    {$WARN identifier ON|OFF}

But it only lists the identifiers for 6 warnings.

I&#39;d like to have a complete list of all the warning identifiers.  In particular, I want to know the identifiers for the implicit string cast warnings W1057 and W1058 in Delphi 2009.

I managed to guess the one for implicit Ansi-&gt;Unicode casts (W1057):

    {$WARN IMPLICIT_STRING_CAST OFF}

Googling for that found me the other one:

    {$WARN IMPLICIT_STRING_CAST_LOSS OFF}

Though that solves my immediate need, I&#39;d still like to know the complete list of warning identifiers.  Stuff like this should be documented.

Identifiers for Delphi&#39;s $WARN compiler directive

*Update 2017-05-17. I no longer work for the company where this question originated, and do not have access to Delphi XEx. While I was there, the problem was solved by migrating to mixed FPC+GCC (Pascal+C), with NEON intrinsics for some routines where it made a difference. (FPC+GCC is highly recommended also because it enables using standard tools, particularly Valgrind.) If someone can demonstrate, with credible examples, how they are actually able to produce optimized ARM code from Delphi XEx, I&#39;m happy to accept the answer.*

______


Embarcadero&#39;s Delphi compilers use an LLVM backend to produce native ARM code for Android devices. I have large amounts of Pascal code that I need to compile into Android applications and I would like to know how to make Delphi generate more efficient code. Right now, I&#39;m not even talking about advanced features like automatic SIMD optimizations, just about producing reasonable code. Surely there must be a way to pass parameters to the LLVM side, or somehow affect the result? Usually, any compiler will have many options to affect code compilation and optimization, but Delphi&#39;s ARM targets seem to be just &quot;optimization on/off&quot; and that&#39;s it.

LLVM is supposed to be capable of producing reasonably tight and sensible code, but it seems that Delphi is using its facilities in a weird way. Delphi wants to use the stack very heavily, and it generally only utilizes the processor&#39;s registers r0-r3 as temporary variables. Perhaps the craziest of all, it seems to be loading normal 32 bit integers as four 1-byte load operations. How to make Delphi produce better ARM code, and without the byte-by-byte hassle it is making for Android? 

At first I thought the byte-by-byte loading was for swapping byte order from big-endian, but that was not the case, it is really just loading a 32 bit number with 4 single-byte loads.*  It might be to load the full 32 bits without doing an unaligned word-sized memory load. (whether it SHOULD avoid that is another thing, which would hint to the whole thing being a compiler bug)*

Let&#39;s look at this simple function:

&lt;!-- language: lang-pascal --&gt;
    
    function ReadInteger(APInteger : PInteger) : Integer;
    begin
      Result := APInteger^;
    end;

Even with optimizations switched on, Delphi XE7 with update pack 1, as well as XE6, produce the following ARM assembly code for that function:

&lt;!-- language: lang-asm --&gt;
    
    Disassembly of section .text._ZN16Uarmcodetestform11ReadIntegerEPi:
    
    00000000 &lt;_ZN16Uarmcodetestform11ReadIntegerEPi&gt;:
       0:	b580      	push	{r7, lr}
       2:	466f      	mov	r7, sp
       4:	b083      	sub	sp, #12
       6:	9002      	str	r0, [sp, #8]
       8:	78c1      	ldrb	r1, [r0, #3]
       a:	7882      	ldrb	r2, [r0, #2]
       c:	ea42 2101 	orr.w	r1, r2, r1, lsl #8
      10:	7842      	ldrb	r2, [r0, #1]
      12:	7803      	ldrb	r3, [r0, #0]
      14:	ea43 2202 	orr.w	r2, r3, r2, lsl #8
      18:	ea42 4101 	orr.w	r1, r2, r1, lsl #16
      1c:	9101      	str	r1, [sp, #4]
      1e:	9000      	str	r0, [sp, #0]
      20:	4608      	mov	r0, r1
      22:	b003      	add	sp, #12
      24:	bd80      	pop	{r7, pc}


Just count the number of instructions and memory accesses Delphi needs for that. And constructing a 32 bit integer from 4 single-byte loads... If I change the function a little bit and use a var parameter instead of a pointer, it is slightly less convoluted:

&lt;!-- language: lang-asm --&gt;
    
    Disassembly of section .text._ZN16Uarmcodetestform14ReadIntegerVarERi:
    
    00000000 &lt;_ZN16Uarmcodetestform14ReadIntegerVarERi&gt;:
       0:	b580      	push	{r7, lr}
       2:	466f      	mov	r7, sp
       4:	b083      	sub	sp, #12
       6:	9002      	str	r0, [sp, #8]
       8:	6801      	ldr	r1, [r0, #0]
       a:	9101      	str	r1, [sp, #4]
       c:	9000      	str	r0, [sp, #0]
       e:	4608      	mov	r0, r1
      10:	b003      	add	sp, #12
      12:	bd80      	pop	{r7, pc}

I won&#39;t include the disassembly here, but for iOS, Delphi produces identical code for the pointer and var parameter versions, and they are almost but not exactly the same as the Android var parameter version. 
*Edit: to clarify, the byte-by-byte loading is only on Android. And only on Android, the pointer and var parameter versions differ from each other. On iOS both versions generate exactly the same code.*

For comparison, here&#39;s what FPC 2.7.1 (SVN trunk version from March 2014) thinks of the function with optimization level -O2. The pointer and var parameter versions are exactly the same.

&lt;!-- language: lang-asm --&gt;
    
    Disassembly of section .text.n_p$armcodetest_$$_readinteger$pinteger$$longint:

    00000000 &lt;P$ARMCODETEST_$$_READINTEGER$PINTEGER$$LONGINT&gt;:
    
       0:	6800      	ldr	r0, [r0, #0]
       2:	46f7      	mov	pc, lr

I also tested an equivalent C function with the C compiler that comes with the Android NDK.

&lt;!-- language: lang-c --&gt;

    int ReadInteger(int *APInteger)
    {
    	return *APInteger;
    }

And this compiles into essentially the same thing FPC made:

&lt;!-- language: lang-asm --&gt;
    
    Disassembly of section .text._Z11ReadIntegerPi:
    
    00000000 &lt;_Z11ReadIntegerPi&gt;:
       0:	6800      	ldr	r0, [r0, #0]
       2:	4770      	bx	lr

How to affect Delphi XEx code generation for Android/ARM targets?

I&#39;m new to Visual Studio 2010 and C#. How can I indent the selected text to left/right by using shortcuts?


![enter image description here][1]


  [1]: http://i.stack.imgur.com/DVw7b.png

In the Delphi IDE the equivalents are &lt;kbd&gt;Ctrl&lt;/kbd&gt;+&lt;kbd&gt;Shift&lt;/kbd&gt;+&lt;kbd&gt;I&lt;/kbd&gt; and &lt;kbd&gt;Ctrl&lt;/kbd&gt;+&lt;kbd&gt;Shift&lt;/kbd&gt;+&lt;kbd&gt;U&lt;/kbd&gt;

Indentation shortcuts in Visual Studio

I&#39;ve created a custom MSBuild `.targets` file that I&#39;ve included in a Delphi XE project via the IDE and enabled it from the Project Manager&#39;s context menu. Although the file validates, it always gets disabled after I re-save the project file.

Here&#39;s a simplified version of the targets file, named `Custom.targets`.

    &lt;Project xmlns=&quot;http://schemas.microsoft.com/developer/msbuild/2003&quot;&gt;
      &lt;Target Name=&quot;Hello&quot;&gt;
        &lt;Message Text=&quot;Hello from custom target&quot;/&gt;
      &lt;/Target&gt;
    &lt;/Project&gt;

As a stand alone file this works as expected: typing...

    MSBuild Custom.target /t:Hello

...at the command line gives the expected message.    

Adding `Custom.targets` to a Delphi project via the IDE displays the file in the Project Manager as expected, and the `.dproj` file now contains the line...

    &lt;TargetsFile Include=&quot;Custom.targets&quot;/&gt;

I right-clicked the file in the IDE&#39;s Project Manager and selected `Enable`. But when the project is built the `Build` message window displays:

&gt; [MSBuild Warning] Custom.targets(1): Ignoring disabled import: `PathToProjectSource\\Custom.targets`

Right-clicking again in Project Manager still shows the `Enable` option instead of the expected `Disable`.

At the command line `MSBuild ProjectName.dproj /t:Hello` also fails.

I&#39;ve tried hacking the `.dproj` file to add the line...

    &lt;Import Project=&quot;Custom.targets&quot;/&gt;

Typing `MSBuild ProjectName.dproj /t:Hello` now works. But the next time I save the project file from the IDE the `&lt;Import&gt;` statement gets removed.

Anyone got any idea what&#39;s going wrong please?

Delphi XE custom build target is always disabled

I have a client/server app which I have been developing on a single PC. Now it needs two serial ports, so I borrowed a PC from a friend.

When I build my app and try to run or debug it (whether in the Delphi IDE or from Windows File manager), it errors &quot;The application was unable to start correctly (0xc000007b)&quot;.

Googling doesn&#39;t bring up much, but seems to indicate that this is nothing Delphi specific and happens with other apps. It seems to be caused by calling into a 32 bit DLL from a 64 bit app or vice versa.

 - both PCs are Windows 7, 64 bit
 - both have Delphi Xe2 starter edition which can only handle 32 bits
 - The app runs fine on my PC, but not on my friend&#39;s
 - Other Delphi apps run just fine on both PCs

Can anyone give me a hint as to how to track this down?

The application was unable to start correctly (0xc000007b)

Delphi used to include a demos folder for web Services, but no longer seems to include this.

I just tried the Delphi 7 demo projects (`SOAPDMServerWAD`, a server with almost no UI at all, and `SOAPDMClient`) and was unable to get them to function, even in Delphi 7.   

If anybody has ever made a similar demo work in Delphi XE, or Delphi 2010, identical to the old `SOAPDMServerWAD+SoapDMClient` demos, working in Delphi XE, and with at least the minimal UI that comes from the Delphi SOAP Server application wizard, that would be perfect.

**Update:** The demo appears all the way up to Delphi 2010 but uses the now-obsoleted WAD (web-app-debugger), I tried to port it to the new Indy `runtime/web-app-development-harnessing-code`, but I can&#39;t seem to get it working. The demo runs, but the server has no User interface, and does not appear to be running any HTTP server (tested using a regular web browser, via `http://localhost:port/` urls.  By the way, try googling for a demo, and this url comes up, and I asked less than an hour ago. That&#39;s scary, google.

**Update2** See my own answer below, a link is coming soon with working code.




SOAP server and client application VCL+indy demo for Delphi XE?

In XCode by adding these methods to your NSView subclass can prevent the window from becoming active when clicking on it:

&lt;!-- language: objective-c --&gt;

    - (BOOL)shouldDelayWindowOrderingForEvent:(NSEvent )theEvent {
        return YES;
    }
    - (BOOL)acceptsFirstMouse:(NSEvent )theEvent {
        return YES; 
    }
    - (void)mouseDown:(NSEvent )theEvent {
        [[[NSApp]] preventWindowOrdering]; 
    }

In Windows platform It is done by this simple code:

&lt;!-- language: c++ --&gt;

    HWND hWnd = FindWindowW((String(&quot;FM&quot;) + fmxForm-&gt;ClassName()).c_str(), 
        fmxForm-&gt;Caption.c_str());
    
    SetWindowLong(hWnd, GWL_EXSTYLE,
        GetWindowLong(hWnd, GWL_EXSTYLE) | WS_EX_NOACTIVATE);

How can I subclass NSView to prevent my FMX TForm becoming active when clicking on it?

How can I create &quot;**No Activate**&quot; form in *firemonkey*?


How to create &quot;No Activate&quot; form in Firemonkey

In Delphi 2009, SysUtils.pas contains this in line 425:

    EProgrammerNotFound = class(Exception);

 - Is this simply an [easter egg][1] or something serious?
 - When should this exception be raised?
 - Does it also exist in Delphi Prism and/or Free Pascal?

----------

Q: Is this exception class still declared in Delphi (currently XE7)?
A: Yes, and it is even [documented][2]!

&gt; Nonstandard way to indicate software faults.
&gt; 
&gt; You can use EProgrammerNotFound as an alternative to indicate software
&gt; faults detected at run time.


  [1]: http://en.wikipedia.org/wiki/Easter_egg_%28media%29#Software-based
  [2]: http://docwiki.embarcadero.com/Libraries/XE7/en/System.SysUtils.EProgrammerNotFound

EProgrammerNotFound exception in Delphi?

As far as I&#39;ve been able to find out, Windows doesn&#39;t offer an API function to tell what application has registered a global hotkey (via RegisterHotkey). I can only find out that a hotkey is registered if RegisterHotkey returns false, but not who &quot;owns&quot; the hotkey.

In the absence of a direct API, could there be a roundabout way? Windows maintains the handle associated with each registred hotkey - it&#39;s a little maddening that there should be no way of getting at this information.

Example of something that likely wouldn&#39;t work: send (simulate) a registered hotkey, then intercept the hotkey message Windows will send to the process that registered it. First, I don&#39;t think intercepting the message would reveal the destination window handle. Second, even if it were possible, it would be a bad thing to do, since sending hotkeys would trigger all sorts of potentially unwanted activity from various programs. 

It&#39;s nothing critical, but I&#39;ve seen frequent requests for such functionality, and have myself been a victim of applications that register hotkeys without even disclosing it anywhere in the UI or docs. 

(Working in Delphi, and no more than an apprentice at WinAPI, please be kind.)

Find out what process registered a global hotkey? (Windows API)

Before I begin, I would like to point out that I have honestly and genuinely searched repeatedly and exhaustively via Google for such a thing, and been unable to find one.

I require (for a project I&#39;m developing) a list of all Delphi (2007 to the very latest released version, I no longer support any version older than 2007) &quot;Language Features&quot;, and the versions in which they were introduced and (where applicable) deprecated, improved or removed.

I have noted similar questions to this on Stack Overflow before, though most of those were phrased in the form of &quot;which feature is best&quot;, and closed as deemed unsuitable.

If anyone knows of such a list (or has enough spare time to compile one), I would be very grateful.

The accepted answer will either contain a link to such a list, or the list itself.

List of Delphi language features and version in which they were introduced/deprecated

When choosing large font sizes in the Windows control panel (like 125%, or 150%) then there are problems in a VCL application, every time something has been set pixelwise.

Take the `TStatusBar.Panel`. I have set its width so that it contains exactly one label, now with big fonts the label &quot;overflows&quot;. Same problem with other components.

Some new laptops from Dell ship already with 125% as default setting, so while in the past this problem was quite rare now it is really important.

What can be done to overcome this problem?

How do I make my GUI behave well when Windows font scaling is greater than 100%

I&#39;m new to Delphi, and I&#39;ve been running some tests to see what object variables and stack variables are initialized to by default:

    TInstanceVariables = class
      fBoolean: boolean; // always starts off as false
      fInteger: integer; // always starts off as zero
      fObject: TObject; // always starts off as nil
    end;

This is the behaviour I&#39;m used to from other languages, but I&#39;m wondering if it&#39;s safe to rely on it in Delphi?  For example, I&#39;m wondering if it might depend on a compiler setting, or perhaps work differently on different machines.  Is it normal to rely on default initialized values for objects, or do you explicitly set all instance variables in the constructor?

As for stack (procedure-level) variables, my tests are showing that unitialized booleans are true, unitialized integers are 2129993264, and uninialized objects are just invalid pointers (i.e. not nil).  I&#39;m guessing the norm is to always set procedure-level variables before accessing them?

Are delphi variables initialized with a value by default?

My goal is:

 - Given a suspended thread in a Delphi-compiled 32 or 64-bit Windows program, to walk the stack (doable)
 - Given stack entries, to enumerate the local variables in each method and their values. That is, at the very least, find their address and type (integer32/64/signed/unsigned, string, float, record, class...) the combination of which can be used to find their value.

The first is fine and it&#39;s the second that this question is about. At a high level, **how do you enumerate local variables given a stack entry in Delphi?**


----------

At a low level, this is what I&#39;ve been investigating:

**RTTI:** does not list this kind of information about methods. This was not something I actually ever thought was a realistic option, but listing here anyway.

**Debug information:** Loading the debug info produced for a debug build.

 - Map files: even a detailed map file (a text-format file! Open one and have a look) does not contain local variable info. It&#39;s basically a list of addresses and source file line numbers. Great for address to file&amp;line correlation, e.g. the blue dots in the gutter; not great for more detailed information
 - Remote debugging information (RSM file) - [no known information][1] on its contents or format.
 - **TD32/TDS files:** my current line of research. They contain global and local symbols among a lot of other information.

The problems I&#39;m encountering here are:

 - There&#39;s no documentation of the TD32 file format (that I can find.)
 - Most of my knowledge of them comes from the Jedi JCL code using them (JclTD32.pas) and I&#39;m not sure how to use that code, or whether the structures there are extensive enough to show local vars. I&#39;m pretty certain it will handle global symbols, but I&#39;m very uncertain about local. There are a wide variety of constants defined and without documentation for the format, to read what they mean, I&#39;m left guessing. However, those constants and their names must come from somewhere.
 - [Source I can find using TDS info][2] does not load or handle local symbols.

If this is the right approach, then this question becomes &#39;Is there documentation for the TDS/TD32 file format, and are there any code samples that load local variables?&#39;

A code sample isn&#39;t essential but could be very useful, even if it&#39;s very minimal.


  [1]: https://stackoverflow.com/questions/10481027/remote-debug-symbol-file-format
  [2]: http://sourceforge.net/p/tds2dbg/wiki/Main_Page/

How do you extract local variable information (address and type) from a Delphi program or the compiler-generated debug info?

I want to create a string that spans multiple lines to assign to a Label Caption property. How is this done in Delphi?

How do I include a newline character in a string in Delphi?

I am trying to detect if a block of memory was not freed. Of course, the manager tells me that by dialog box or log file, but what if I would like to store results in a database? For example I would like to have in a database table a names of routines which allocated given blocks.

After reading a documentation of FastMM I know that since version 4.98 we have a possibility to be notified by manager about memory allocations, frees and reallocations as they occur. For example `OnDebugFreeMemFinish` event is passing to us a `PFullDebugBlockHeader` which contains useful informations.
There is one thing that `PFullDebugBlockHeader` is missing - the information if the given block was freed by the application.

**Unless `OnDebugFreeMemFinish` is called only for not freed blocks? This is which I do not know and would like to find out.**

The problem is that even hooking into `OnDebugFreeMemFinish` event I was unable to find out if the block was freed or not.

Here is an example:

    program MemLeakTest;
    
    {$APPTYPE CONSOLE}
    
    uses
      FastMM4, ExceptionLog, SysUtils;
    
    
    procedure MemFreeEvent(APHeaderFreedBlock: PFullDebugBlockHeader; AResult: Integer);
    begin
    //This is executed at the end, but how should I know that this block should be freed
    //by application? Unless this is executed ONLY for not freed blocks.
    end;
    
    procedure Leak;
    var
      MyObject: TObject;
    begin
      MyObject := TObject.Create;
    end;
    
    begin
      OnDebugFreeMemFinish := MemFreeEvent;
      Leak;
    end.

What I am missing is the callback like:

    procedure OnMemoryLeak(APointer: PFullDebugBlockHeader);

After browsing the source of FastMM I saw that there is a procedure:

    procedure LogMemoryLeakOrAllocatedBlock(APointer: PFullDebugBlockHeader; IsALeak: Boolean);

which could be overriden, but maybe there is an easier way?


Is there a way to programmatically tell if particular block of memory was not freed by FastMM?

I am using the `XML Data Binding Wizard` in `Delphi XE2`.
The schema has required tags of this type:

    &lt;xs:element name=&quot;MyReport&quot; type=&quot;MyReportType&quot; /&gt;
    &lt;xs:complexType name=&quot;MyReportType&quot;&gt;
      &lt;xs:all&gt;
        &lt;xs:element name=&quot;Header&quot; type=&quot;HeaderType&quot; /&gt;
        &lt;xs:element name=&quot;Values&quot; type=&quot;ValuesType&quot; /&gt;
        &lt;xs:element name=&quot;Events&quot; type=&quot;EventsType&quot; /&gt;
      &lt;/xs:all&gt;
    &lt;/xs:complexType&gt;

The problem is that if I don&#39;t add any elements to e.g. the `Values`-group, there will be no `&lt;Values&gt;`-tag, and the XML-file will fail validation against the `XSD`. This probably would not be a problem if the interface was providing a method for &quot;adding&quot; the `Values`-tag.

Is there a standard way of handling this, or am I using the generated code in-correctly?

**Put simply**, is there *any* way, work-around or otherwise, using the code from the `Data Binding Wizard`, to produce the following `XML` (which is what is needed to validate using the above schema when there are no child nodes), given `HeaderType`, `ValuesType` and `EventsType` are of complexType:

    &lt;MyReport&gt;
      &lt;Header /&gt;
      &lt;Values /&gt;
      &lt;Events /&gt;
    &lt;/MyReport&gt; 

(I know there are other similar issues, like the code generated by `&lt;xs:sequence&gt;` not enforcing the correct order in the final `XML`-file, but at least for that one, there&#39;s a work-around by simply inserting the children in the right order. I still think it would be nice if `Embarcadero` would provide a complete interface, which takes more of these features into account.)

Required tags not present when using Delphi XML Data Binding Wizard

I&#39;m trying to find a Delphi function that will split an input string into an array of strings based on a delimiter. I&#39;ve found a lot from searching the web, but all seem to have their own issues and I haven&#39;t been able to get any of them to work.

I just need to split a string like: 
`&quot;word:doc,txt,docx&quot;` into an array based on &#39;:&#39;. The result would be 
`[&#39;word&#39;, &#39;doc,txt,docx&#39;]`. How can I do that?


Split a string into an array of strings based on a delimiter

I asked a similar [question][1] about implicit interface variables not so long ago.

The source of this question was a bug in my code due to me not being aware of the existence of an implicit interface variable created by the compiler. This variable was finalized when the procedure that owned it finished. This in turn caused a bug due to the lifetime of the variable being longer than I had anticipated.

Now, I have a simple project to illustrate some interesting behaviour from the compiler:

    program ImplicitInterfaceLocals;
    
    {$APPTYPE CONSOLE}
    
    uses
      Classes;
    
    function Create: IInterface;
    begin
      Result := TInterfacedObject.Create;
    end;
    
    procedure StoreToLocal;
    var
      I: IInterface;
    begin
      I := Create;
    end;
    
    procedure StoreViaPointerToLocal;
    var
      I: IInterface;
      P: ^IInterface;
    begin
      P := @I;
      P^ := Create;
    end;
    
    begin
      StoreToLocal;
      StoreViaPointerToLocal;
    end.

`StoreToLocal` is compiled just as you would imagine. The local variable `I`, the function&#39;s result, is passed as an implicit `var` parameter to `Create`. The tidy up for `StoreToLocal` results in a single call to `IntfClear`. No surprises there.

However, `StoreViaPointerToLocal` is treated differently. The compiler creates an implicit local variable which it passes to `Create`. When `Create` returns, the assignment to `P^` is performed. This leaves the routine with two local variables holding references to the interface. The tidy up for `StoreViaPointerToLocal` results in two calls to `IntfClear`.

The compiled code for `StoreViaPointerToLocal` is like this:

    ImplicitInterfaceLocals.dpr.24: begin
    00435C50 55               push ebp
    00435C51 8BEC             mov ebp,esp
    00435C53 6A00             push $00
    00435C55 6A00             push $00
    00435C57 6A00             push $00
    00435C59 33C0             xor eax,eax
    00435C5B 55               push ebp
    00435C5C 689E5C4300       push $00435c9e
    00435C61 64FF30           push dword ptr fs:[eax]
    00435C64 648920           mov fs:[eax],esp
    ImplicitInterfaceLocals.dpr.25: P := @I;
    00435C67 8D45FC           lea eax,[ebp-$04]
    00435C6A 8945F8           mov [ebp-$08],eax
    ImplicitInterfaceLocals.dpr.26: P^ := Create;
    00435C6D 8D45F4           lea eax,[ebp-$0c]
    00435C70 E873FFFFFF       call Create
    00435C75 8B55F4           mov edx,[ebp-$0c]
    00435C78 8B45F8           mov eax,[ebp-$08]
    00435C7B E81032FDFF       call @IntfCopy
    ImplicitInterfaceLocals.dpr.27: end;
    00435C80 33C0             xor eax,eax
    00435C82 5A               pop edx
    00435C83 59               pop ecx
    00435C84 59               pop ecx
    00435C85 648910           mov fs:[eax],edx
    00435C88 68A55C4300       push $00435ca5
    00435C8D 8D45F4           lea eax,[ebp-$0c]
    00435C90 E8E331FDFF       call @IntfClear
    00435C95 8D45FC           lea eax,[ebp-$04]
    00435C98 E8DB31FDFF       call @IntfClear
    00435C9D C3               ret 

I can guess as to why the compiler is doing this. When it can prove that assigning to the result variable will not raise an exception (i.e. if the variable is a local) then it uses the result variable directly. Otherwise it uses an implicit local and copies the interface once the function has returned thus ensuring that we don&#39;t leak the reference in case of an exception.

But I cannot find any statement of this in the documentation. It matters because interface lifetime is important and as a programmer you need to be able to influence it on occasion.

So, does anybody know if there is any documentation of this behaviour? If not does anyone have any more knowledge of it? How are instance fields handled, I have not checked that yet. Of course I could try it all out for myself but I&#39;m looking for a more formal statement and always prefer to avoid relying on implementation detail worked out by trial and error.

**Update 1**

To answer Remy&#39;s question, it mattered to me when I needed to finalize the object behind the interface before carrying out another finalization.

    begin
      AcquirePythonGIL;
      try
        PyObject := CreatePythonObject;
        try
          //do stuff with PyObject
        finally
          Finalize(PyObject);
        end;
      finally
        ReleasePythonGIL;
      end;
    end;

As written like this it is fine. But in the real code I had a second implicit local which was finalized after the GIL was released and that bombed. I solved the problem by extracting the code inside the Acquire/Release GIL into a separate method and thus narrowed the scope of the interface variable.



  [1]: https://stackoverflow.com/questions/5354696/the-mysterious-case-of-the-unexpected-implicit-interface-variable



Is the compiler treatment of implicit interface variables documented?

Say you have a menu item and a button that do the same task.
Why is it bad practice to put the code for the task into one control&#39;s action event and then make a call to that event from the other control?
Delphi allows this as  does vb6 but realbasic doesn&#39;t and says you should put the code into a method that is then called by both the menu and the button

Why is it bad practice to call an eventhandler from code?

I have started to convert the Webview interfaces to be consumed in Delphi.  I have managed to get the webkit library to load, and the interface methods that is called appears to work correctly, however, I cannot seem to display the Webview on the main form.

Below is my interfaces that is declared

      WebFrameClass = interface(NSObjectClass)
      [&#39;{7BE750C8-DFEC-4870-851A-12DBCB0B78F6}&#39;]
      end;
    
      WebFrame = interface(NSObject)
      [&#39;{BCFA04BE-41AB-4B78-89C0-3330F12C7695}&#39;]
        procedure loadRequest(request: NSURLRequest); cdecl;
      end;
      TWebFrame = class(TOCGenericImport&lt;WebFrameClass, WebFrame&gt;)  end;
    
      WebViewClass = interface(NSViewClass)
      [&#39;{0D9F44B7-09FD-4E35-B96E-8DB71B9A2537}&#39;]
        {class} function canShowMIMEType(MIMEType: NSString): Boolean; cdecl;
      end;
    
      WebView = interface(NSView)
      [&#39;{C36D8016-2FCB-49F0-BA1C-C9913A37F9AC}&#39;]
        procedure clos; cdecl;
        procedure setHostWindow(hostWindow: NSWindow); cdecl;
        function initWithFrame(frame: NSRect; frameName: NSString; groupName: NSString): Pointer; cdecl;
        function mainFrame: WebFrame; cdecl;
      end;
      TWebView = class(TOCGenericImport&lt;WebViewClass, WebView&gt;)  end;

And here follows to code to construct a WebView:

    procedure TForm2.Button1Click(Sender: TObject);
    var
      PWebView: Pointer;
      FwkMod: HMODULE;
      MyWebView: WebView;
      urlStr: NSURL;
      urlreq: NSURLRequest;
    const
      WebKitFWK: string = &#39;/System/Library/Frameworks/WebKit.framework/WebKit&#39;;
    begin
      FwkMod := System.SysUtils.LoadLibrary(PWideChar(WebKitFWK));
      PWebView := TWebView.Alloc.initWithFrame(MakeNSRect(10, 10, 300, 300), nil, nil);
      MyWebView := TWebView.Wrap(PWebView);
    
      urlStr := TNSURL.Create;
      urlstr.initWithString(NSSTR(&#39;http://google.com.au/&#39;));
      urlreq := TNSURLRequest.Create;
      urlreq.initWithURL(urlstr);
      MyWebView.mainFrame.loadRequest(urlreq);
    end;

The code executes without raising any exceptions, but just does not want to appear.  What needs to be done differently in Delphi? The examples I found for objective C appears to be quite simple:

Some objective C examples I have seen mention IBOutlets.  It does not look like this is relevant for Delphi. 

https://stackoverflow.com/questions/4777490/how-to-make-webview-osx-xcode-project-load-a-url-on-launch

Thanks.





Webview not displaying in MacOS using Delphi XE2

I&#39;ve built an App on Android using Delphi XE6 that requires C code. However on iOS I cannot make it work. I suspect the problem is related to arm/thumb status, but I am not sure. There is no problem in either system to call the C code from Pascal. But if the C code calls back a Pascal procedure iOS generates a `&quot;bad system call (12)&quot;`

Here is the pascal code:

    function testarm(a,b:integer):integer; cdecl; external &quot;testC.o&quot;;
        
    Procedure testC;
    Begin
      testarm(1,2);
    end;
            
    function BackToPascal(a,b:integer): integer; cdecl;
      Begin
      result := a+b;
    end;
        
    ......
        
    exports
      BackToPascal;
        

And here is the C code:

    extern int BackToPascal(int a,int b);
    
    extern int testarm(int a,int b)
    {
       int i;
       i = BackToPascal(a,b);
       return i+1;
    }

On android this is how I am compiling (It is working):

    ...&quot;arm-linux-androideabi-gcc.exe&quot; -c test.c -o test.o -O3 -mfloat-abi=softfp -mfpu=neon -marm -march=armv7-a -mtune=cortex-a8

On ios:

    xcrun -sdk iphoneos clang -c -arch armv7 test.c -O3 -mfpu=neon -mtune=cortex-a8 -marm -march=armv7-a -mfloat-abi=softfp

I suspect that my xcode settings are wrong but I cannot figure out why.

When I debug, the error comes when calling `testC` in `testarm` when calling `BackToPascal` ( on &quot;bl 0x8b8390 Xgobj.BackToPascal (int, int)&quot; ). On Android it works perfect however the `bl` does not call directly `BackToPascal`, but the following code:

    75A82D94 12C68FE2         add r12, pc, #18874368 ; 0x1200000
    75A82D98 73CA8CE2         add r12, r12, #471040 ; 0x73000
    75A82D9C 40F2BCE5         ldr pc, [r12, #576]! ; 0x240

Which get into `BackToPascal` 



Delphi XE6 link C code in iOS

`FmtBcd.pas` has been extensively revised rewritten in Delphi XE2. In one of my projects, I have a case that uses a division operation on two `Bcd` values, but the two versions yield different results. In the worst case, the Delphi XE2 may throw a `Bcd overflow error`.

Example: Running the following code in Delphi XE2 console apps:

    var A, B, C, D: TBcd;
    begin
      A := StrToBcd(&#39;1&#39;);
      B := StrToBcd(&#39;3&#39;);
      BcdDivide(A, B, C);
      WriteLn(BcdToStr(C));

      try
        BcdMultiply(C, C, D);
        WriteLn(BcdToStr(D));
      except
        on E: Exception do
          WriteLn(E.Message);
      end;

      ReadLn;
    end.

Output of the above will be:

    0.333333333333333333333333333333333333333333333333333333333333333
    BCD overflow

The variable `C` contains a Bcd Value with 63 decimal places of specificity. Performing a second `BcdMultiply` operation on variable `C` will cause a `Bcd overflow error`.

However, to run the same code in Delphi XE yields the following result without any exception prompt:

    0.3333333333
    0.11111111108888888889

Could anyone please suggest a best-practice method for resolving this problem?

BcdDivide function behave differently in Delphi XE and XE2

It seems that I&#39;ve finally got to implement some sort of threading into my Delphi 2009 program. If there were only one way to do it, I&#39;d be off and running. But I see several possibilities.

Can anyone explain what&#39;s the difference between these and why I&#39;d choose one over another.

 1. The TThread class in Delphi

 2. [AsyncCalls][1] by [Andreas Hausladen][2]

 3. [OmniThreadLibrary][3] by [Primoz Gabrijelcic (gabr)][4]

 4. ... any others?

---

Edit:

I have just read an excellent article by Gabr in the March 2010 (No 10) issue of [Blaise Pascal Magazine][5] titled &quot;Four Ways to Create a Thread&quot;. You do have to subscribe to gain content to the magazine, so by copyright, I can&#39;t reproduce anything substantial about it here.

In summary, Gabr describes the difference between using TThreads, direct Windows API calls, Andy&#39;s AsyncCalls, and his own OmniThreadLibrary. He does conclude at the end that:

&gt; &quot;I&#39;m not saying that you have to choose anything else than the classical Delphi way (TThread) but it is still good to be informed of options you have&quot;

Mghie&#39;s answer is very thorough and suggests OmniThreadLibrary may be preferable. But I&#39;m still interested in everyone&#39;s opinions about how I (or anyone) should choose their threading method for their application. 

And you can add to the list:

. 4. Direct calls to the Windows API

. 5. [Misha Charrett&#39;s][6] [CSI Distributed Application Framework][7] as suggested by LachlanG in his answer.

---

Conclusion:

I&#39;m probably going to go with OmniThreadLibrary. I like Gabr&#39;s work. I used his profiler GPProfile many years ago, and I&#39;m currently using his GPStringHash which is actually part of OTL.

My only concern might be upgrading it to work with 64-bit or Unix/Mac processing once Embarcadero adds that functionality into Delphi.

 


  [1]: http://andy.jgknet.de/blog/?page_id=100
  [2]: https://stackoverflow.com/users/44005/andreas-hausladen
  [3]: http://otl.17slon.com/
  [4]: https://stackoverflow.com/users/4997/gabr
  [5]: http://www.blaisepascal.eu/
  [6]: https://stackoverflow.com/users/195109/misha
  [7]: http://csinnovations.com/framework/framework.htm

How Do I Choose Between the Various Ways to do Threading in Delphi?

I am currently using Delphi XE2, and heard about their new Live Binding with Automatic updates in XE3 (no need to call Notify() as in XE2).

in C# or in Delphi XE2 we have to implement `INotifyPropertyChanged` (`Notify();` in Delphi), and this approach really makes sense as we have full control over the contents to be updated and when to update it so we can fine tune the performance and implement virtualization easily.

But I just want to know how does it works, what kind of mechanism they have done in order to implement it, and i have no clue how they have did it, following are the assumptions may have used to implement Automatic updates.

 1. Timer : A timer tick frequently and refreshes all the data 
&gt; *Very slow performance no virtualization*

 1. Compiler Level Feature : All the `notify() events` related codes implemented by the compiler auto-magically 
&gt; *Lots of over heads*

 1. Somme other Approach: 

Please help me to identified how they have implemented it.

I am currently using XE3 trial so i don&#39;t have access to the source code, **your answers will help me decide whether to switch to new features or not**. &lt;br&gt; I have a class(collection item) with 400 properties to bind(Not all of them all the time), so the performance really plays a major role in the stability of my application.  
  

Live Binding with Automatic updates in XE3 (no need to call Notify() as in XE2)

I&#39;ve seen it happen reasonably often: I write an application in Delphi and when I compile it, the virus-scanner tells me that I&#39;ve created a virus and then immediately deletes the executable again. It&#39;s annoying but reasonable easy to fix by doing a full rebuild, deleting the *.dcu files first and sometimes by simply waiting.

It happens with Delphi 6, 7, 2005 and 2007, as far as I know. And Symantec, Kaspersky, McAfee and NOD32 have all been guilty of reporting these false positives. I know it&#39;s because Delphi adds timestamps to its DCU files and these timestamps end up in the final executable and apparently appear to be part of some random virus signature.

I don&#39;t want to disable the virus-scanner, not even for a single folder or file. And I&#39;m not really for a solution, but am wondering about the following:

* Do these false positives also occur with other compilers?
* Does it also happen with .NET executables?
* Do others also notice similar problems with Delphi?

Accidentally created a virus?

&gt; **Possible Duplicate:**  
&gt; [How to also prepare for 64-bits when migrating to Delphi 2010 and Unicode](https://stackoverflow.com/questions/1568685/how-to-also-prepare-for-64-bits-when-migrating-to-delphi-2010-and-unicode)  

&lt;!-- End of automatically inserted text --&gt;

Since I believe that **64bit** Delphi compiler will appear soon,
I am curious if anybody knows what kind of programs
that are now **32bit** will compile and work without any changes
when using **64bit** compiler.

And if there is a general rule what kind of changes should we 
systematically make in our old programs to be compiled
as **64bit**?

It is good to be prepared when the  **64bit** compiler will suddenly be here...

Any suggestion will be much appreciated. 
 



How should I prepare my 32-bit Delphi programs for an eventual 64-bit compiler?

I&#39;m wondering how the few Delphi users here are doing unit testing, if any?  Is there anything that integrates with the IDE that you&#39;ve found works well?  If not, what tools are you using and do you have or know of example mini-projects that demonstrate how it all works?

### Update:
I forgot to mention that I&#39;m using BDS 2006 Pro, though I occasionally drop into Delphi 7, and of course others may be using other versions.

Unit testing in Delphi - how are you doing it?

Has anyone seen a recent (and fairly balanced) study into the relative costs for software development using differing languages ? I would particular like to see the relative costs of Java Vs. C# Vs. Delphi.

Studies of relative costs for development in different languages

I&#39;d really like to know the various ways I could select a directory with the TOpenDialog, whether it be downloading a new component or using what is provided by Delphi, but preferably using what is provided by Delphi. 

Prior to this, I have been using the SelectDirectory command but I think it&#39;d be a difficulty for the users of my program to look for the specified directory.

I think the SelectDirectory is &#39;weak&#39; because it can be a long process when searching for the directory you want. Say for example, you want to navigate to the Application Data directory. How long or difficult would it be to navigate there? In the end, users may not even reach their desired directory. 

I need something like this where the user can copy and paste directories into the directory address bar at the top there.

![enter image description here][1]


Thank you for all your answers.


  [1]: http://i.stack.imgur.com/hQ9vy.png

Selecting a directory with TOpenDialog

What&#39;s the difference between parameters declared with `var` and those declared with `out`? How does the compiler treat them differently (e.g., by generating different code, or by changing which diagnostics it issues)? Or do the different modifiers merely allow the programmer to document intended use of the parameters? What effect do the *types* of the parameters have on the matter?

What&#39;s the difference between &quot;var&quot; and &quot;out&quot; parameters?

I am having trouble with the delimiter in the TStringList Class. Take a look:

    var
      s: string;
      sl: TStringList;
    
    begin
      sl := TStringList.Create;
      s := &#39;Users^foo bar^bar foo^foobar^barfoo&#39;;
      sl.Delimiter := &#39;^&#39;;
      sl.DelimitedText := s;
      ShowMessage(sl[1]);
    end;

`sl[1]` SHOULD return `&#39;foo bar&#39;`

`sl[1]` DOES return `&#39;foo&#39;`

It seems that the delimiter is now `&#39;^&#39;` AND `&#39; &#39;`

Any ideas?

Delphi: StringList Delimiter is always a space character even if Delimiter is set

This question is a continuance of a particular comment from people on stackoverflow which I&#39;ve seen a few different times now. I, along with the developer who taught me Delphi, in order to keep things safe, have always put a check `if assigned()` before freeing objects, and before doing other various things. However, I&#39;m now told that I should *not* be adding this check. I&#39;d like to know if there is any difference in how the application compiles/runs if I do this, or if it won&#39;t affect the result at all...

    if assigned(SomeObject) then SomeObject.Free;

Let&#39;s say I have a form, and I&#39;m creating a bitmap object in the background upon the form&#39;s creation, and freeing it when I&#39;m done with it. Now I guess my problem is I got too used to putting this check on a lot of my code when I&#39;m trying to access objects which might potentially have been free&#39;d at some point. I&#39;ve been using it even when it&#39;s not necessary. I like to be thorough...

    unit Unit1;
    
    interface
    
    uses
      Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
      Dialogs;
    
    type
      TForm1 = class(TForm)
        procedure FormCreate(Sender: TObject);
        procedure FormDestroy(Sender: TObject);
      private
        FBitmap: TBitmap;
      public
        function LoadBitmap(const Filename: String): Bool;
        property Bitmap: TBitmap read FBitmap;
      end;
    
    var
      Form1: TForm1;
    
    implementation
    
    {$R *.dfm}
    
    procedure TForm1.FormCreate(Sender: TObject);
    begin
      FBitmap:= TBitmap.Create;
      LoadBitmap(&#39;C:\Some Sample Bitmap.bmp&#39;);
    end;
    
    procedure TForm1.FormDestroy(Sender: TObject);
    begin
      if assigned(FBitmap) then begin //&lt;-----
        //Do some routine to close file
        FBitmap.Free;
      end;
    end;
    
    function TForm1.LoadBitmap(const Filename: String): Bool;
    var
      EM: String;
      function CheckFile: Bool;
      begin
        Result:= False;
        //Check validity of file, return True if valid bitmap, etc.
      end;
    begin
      Result:= False;
      EM:= &#39;&#39;;
      if assigned(FBitmap) then begin //&lt;-----
        if FileExists(Filename) then begin
          if CheckFile then begin
            try
              FBitmap.LoadFromFile(Filename);
            except
              on e: exception do begin
                EM:= EM + &#39;Failure loading bitmap: &#39; + e.Message + #10;
              end;
            end;
          end else begin
            EM:= EM + &#39;Specified file is not a valid bitmap.&#39; + #10;
          end;
        end else begin
          EM:= EM + &#39;Specified filename does not exist.&#39; + #10;
        end;
      end else begin
        EM:= EM + &#39;Bitmap object is not assigned.&#39; + #10;
      end;
      if EM &lt;&gt; &#39;&#39; then begin
        raise Exception.Create(&#39;Failed to load bitmap: &#39; + #10 + EM);
      end;
    end;
    
    end.

Now let&#39;s say I&#39;m introducing a new custom list object called `TMyList` of `TMyListItem`. For each item in this list, of course I have to create/free each item object.  There&#39;s a few different ways of creating an item, as well as a few different ways of destroying an item (Add/Delete being the most common). I&#39;m sure it&#39;s a very good practice to put this protection here...

    procedure TMyList.Delete(const Index: Integer);
    var
      I: TMyListItem;
    begin
      if (Index &gt;= 0) and (Index &lt; FItems.Count) then begin
        I:= TMyListItem(FItems.Objects[Index]);
        if assigned(I) then begin //&lt;-----
          if I &lt;&gt; nil then begin
            I.DoSomethingBeforeFreeing(&#39;Some Param&#39;);
            I.Free;
          end;
        end;
        FItems.Delete(Index);
      end else begin
        raise Exception.Create(&#39;My object index out of bounds (&#39;+IntToStr(Index)+&#39;)&#39;);
      end;
    end;

In many scenarios, at least I would hope that the object is still created before I try to free it. But you never know what slips might happen in the future where an object gets free&#39;d before it&#39;s supposed to. I&#39;ve always used this check, but now I&#39;m being told I shouldn&#39;t, and I still don&#39;t understand why.

----------

**EDIT**

Here&#39;s an example to try to explain to you why I have a habit of doing this:

    procedure TForm1.FormDestroy(Sender: TObject);
    begin
      SomeCreatedObject.Free;
      if SomeCreatedObject = nil then
        ShowMessage(&#39;Object is nil&#39;)
      else
        ShowMessage(&#39;Object is not nil&#39;);
    end;

My point is that `if SomeCreatedObject &lt;&gt; nil` is not the same as `if Assigned(SomeCreatedObject)` because after freeing `SomeCreatedObject`, it does not evaluate to `nil`. So both checks should be necessary.


Why should I not use &quot;if Assigned()&quot; before accessing objects?

I&#39;m remote debugging a large app between DElphi XE2 (update #4) and a Windows XP target. PAServer is running on the target and the application works fine and stops at breakpoints (you would NOT believe how hard just that achievement was - hint - delete your DPROJ and start again if it has been through any IDE prior to XE).

I notice that the display of local variables and watches show my strings in a strange format compared to the usual display of the &#39;some string&#39; format that one sees when debugging locally. I see:

![enter image description here][1]

Can anyone tell me why the strings are displayed this way? I also get quite a bit of { NULL } and garbage between {}&#39;s on output variables that are not yet assigned.
Thanks.

&lt;Later edit&gt;. I see that this format indicates wide strings. I tried a simple app on Windows 7 and got the following result. My App at a breakpoint:

![enter image description here][2]

The displayed local string variables:

![enter image description here][3]

Note the truncated &#39;Hello&#39;. It would seem that XE2 has a problem with remote unicode strings at times. My PaServer is version 1.0.2. Can anyone check that this is the latest? &#39;Twas taken from Update #4...


  [1]: http://i.stack.imgur.com/kSq2Q.png
  [2]: http://i.stack.imgur.com/XyI23.png
  [3]: http://i.stack.imgur.com/q4FHB.png

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