The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

  • My badges

    Mastodon

  • Twitter Updates

  • My Flickr Stream

    20140508-Delphi-2007--Project-Options--Cannot-Edit-Application-Title-HelpFile-Icon-Theming20140430-Fiddler-Filter-Actions-Button-Run-Filterset-now20140424-VMware-Fusion-6.0.3.-no-reclaimable
    More Photos

  • Pages

  • All categories

  • Enter your email address to subscribe to this blog and receive notifications of new posts by email.

    Join 1,862 other subscribers

Archive for April, 2019

« Previous Entries
Next Entries »

When generics and VCL controls bite you: memory overwrites when you show the control usually ending up in access violations

Posted by jpluimers on 2019/04/09

Recently I got bitten by the 2013 reported http://qc.embarcadero.com/wc/qcmain.aspx?d=112101 (too bad the site is gone and the WayBack machine doesn’t have it archived) as a result of [WayBack] delphi – Why do I get access violations when a control’s class name is very, very long? – Stack Overflow.

It got reentered as [RSP-18399] Buffer overflow in TWinControl.CreateParams() – Embarcadero Technologies but since that requires logon, it’s not search machine indexed so it’s very hard to find unless you know where to look.

So I spent a quite some time to find out what was wrong:

Since Delphi 1, the [WayBack] Controls.TCreateParams Record has a 64-byte WinClassName field that’s blindingly copied by the TWinControl.CreateParams without range checking.

The structure is used by the [WayBack] TWinControl.CreateWnd Method to call the Windows API [WayBack] RegisterClass function that takes a [WayBack] WNDCLASS structure with a lpszClassName field that supports up to 256 characters and it fails when it’s longer.

That overwrite cause spurious other errors depending on the memory that gets overwritten. It took almost a day to figure out the cause of the error was this field, then an hour or to track that down to the long class names created by generic code.

To my surprise, I found back [WayBack] This issue caused coworkers and me quite a few hours wasted:Long story short – refactor some forms/frames to class names longer than 64 chars and boom… – Stefan Glienke – Google+.

As of Delphi 8 (yes, that version that a lot of people want to forget, but did bring a few good things), the structure was defined as below, and the code intialising also got improved:

Params.WinClassName := ClassName;
...
Params.WinClassName := Format('%s.%d', [Params.WinClassName, AppDomain.CurrentDomain.GetHashCode]);

So there it’s a string that – if it is too long – will get rejected by the Windows API anyway just like the native Delphi VCL implementation should have done 20+ years ago.

The sad part for FMX users: that structure and code got blindingly copied to the FMX.Controls.Win unit.

Read the rest of this entry »

Posted in Delphi, Development, Software Development | Leave a Comment »

Adobe Acrobat Reader – Content Preparation Progress window

Posted by jpluimers on 2019/04/08

I hope this gets rid of the content preparation progress window:

Disable the screen reader options in Adobe Acrobat:

  1. Within Adobe Acrobat, go to “Edit > Preferences > Reading”
  2. Locate the “Screen Reader Options” section.
  3. In the ‘Page vs Document’ dropdown box choose “Only read the currently visible pages”, and uncheck “Confirm before tagging documents”.

–jeroen

Read the rest of this entry »

Posted in Adobe, Adobe Acrobat, Adobe Reader, Power User | 2 Comments »

Research list: machine sometimes not visible on LAN

Posted by jpluimers on 2019/04/08

When one of the machine isn’t active for a while it seems to disappear. Even when it’s active some of the machines have intermittent errors pinging it as like every 10-30 seconds one of these ping results appear:

92 bytes from tl-er5120 (192.168.71.1): Redirect Host(New addr: 192.168.71.193)
Vr HL TOS  Len   ID Flg  off TTL Pro  cks      Src      Dst
 4  5  00 0054 05de   0 0000  40  01 644d 192.168.71.108  192.168.71.193

Sometimes even a simple

Request timeout for icmp_seq 6900

So I need to dig into  ICMP “Redirect Host” .

It might be a simple ARP thing like mac mini – Why the different results for ping? Or why is the Time Capsule getting involved? – Ask Different [WayBack] but like usual stuff I bump into is of a more complex kind so I’ve archived at least these:

–jeroen

Posted in Internet, MikroTik, Power User, routers | Leave a Comment »

Ich brauch gerade mal Nachhilfe in uBlock Syntax. Wo kann man Beispiele lese…

Posted by jpluimers on 2019/04/08

For my link archive:

On uBlock, uMatrix, Personal Blocklist, Google Chrome Site Settings and others.

–jeroen

Posted in Chrome, Google, Power User | Leave a Comment »

Blast from the past: “Advanced Pascal Programming Techniques” – Google Search

Posted by jpluimers on 2019/04/05

Back in my school days, this was the best Pascal book you could get: “Advanced Pascal Programming Techniques” – Google Search.

This is Apple Pasca, USD Pascal, first Turbo Pascal era.

Sadly, getting English books in The Netherlands was hard. So I had to do with books from Academic Press which not as good.

Via:

–jeroen

Posted in Apple Pascal, Borland Pascal, Development, History, Pascal, Software Development, Turbo Pascal, UCSD Pascal | 1 Comment »

How to activate ADB & Helium on OnePlus 2 on Mac – OnePlus Forums

Posted by jpluimers on 2019/04/05

The quoted link wasn’t in the end what I used to get my config from a OnePlus 2 to a OnePlus 5

How to activate ADB & Helium on OnePlus 2 on Mac – OnePlus Forums « The Wiert Corner – irregular stream of stuff.

This is what I had to do instead:

  1. On the OnePlus 2:
    1. Enable developer mode (see Android 4.2+: enable USB debug mode (Nexus 4, Nexus 7, etc) orA few OnePlus One CyanogenMod tips)
    2. Enable USB debugging
    3. Install the Helium Android App from play.google.com/store/apps/details?id=com.koushikdutta.backup
    4. Run Helium
    5. Wait for activation
  2. On my Mac:
    1. Install the Mac version of Helium from http://download.clockworkmod.com/carbon/carbon-mac.zip
    2. Run the Mac version of Helium from
    3. Connect the USB cable to the OnePlus 2
    4. Wait for the Mac version of Helium to have “enabled” Helium on the One Plus 2
    5. Quit the Mac version of Helium
    6. Install the Chrome version of Helium from https://chrome.google.com/webstore/detail/helium-backup/gpglbgbpeobllokpmeagpoagjbfknanl?authuser=1
    7. Run the Chrome version of Helium
    8. Wait for the Chrome version of Helium to complete the activation of Helium on the Ons Plus 2
  3. On the One Plus 2:
    1. Select the applications to backup
    2. Back up

Relevant links:

–jeroen

Posted in Android Devices, Helium, OnePlus Five, OnePlus Two, Power User | Leave a Comment »

Product Graveyard: Commemorating the most memorable dead products

Posted by jpluimers on 2019/04/05

Some of those past products you’d loved are now at [Archive.is] Product Graveyard: Commemorating the most memorable dead products

It lists alternatives too at the bottom of each obituary, which might help you find a replacement for tools you had a crush on.

From their featured products list, I miss these the most:

Starting in august 2017, I’m curious to see how long the site itself lasts…

–jeroen

via: [WayBack] Product GraveyardWhat an interesting site. Obituary notices for products that at one time may have been famous and widely used. You can even find a… – Lars Fosdal – Google+

 

Posted in History, Power User | Leave a Comment »

Detecting if a debugger is present is different from detecting if an IDE is present.

Posted by jpluimers on 2019/04/04

I have seen this happen in various environments: people wanting to detect if their debugger is present, but trying to detect their IDE, or vice versa.

Similar reasoning is for detecting for being running on a console, or your project having been built to run on a console.

People use these decisions, for instance to determine if their application should behave as a service, or as a regular process.

Ways to determine the various permutation points:

  • Running inside a debugger: use the [WayBack] IsDebuggerPresent function (which can be true, even if Delphi DebugHook stays zero).
  • Check for the IDE: tricky; as IDEs have different behaviour over time. For Delphi, check for any TAppBuilder Window class with the [WayBack] FindWindow function.
  • Compiled for console: for Delphi check IsConsole, for .NET I could not find good information.
  • Running on a console: check if you can allocate a handle to stdout
  • Running as a service: check the hosting assembly or hosting process

Related links:

–jeroen

Posted in .NET, Delphi, Development, Software Development, Windows Development | Leave a Comment »

Firemonkey/Isometric at master · tothpaul/Firemonkey

Posted by jpluimers on 2019/04/04

This shows you how to do 2.5D isometric projection in Delphi using Firemonkey: [WayBack] Firemonkey/Isometric at master · tothpaul/Firemonkey.

[WayBack] Isometric projection – Wikipedia.

Via: [WayBack] I wonder what the best approach would be to use FireMonkey to develop an isometric 2.5D game in the “classic” way… – Fl Ko – Google+

–jeroen

Posted in Delphi, Development, FireMonkey, Software Development | Leave a Comment »

Delphi: do NOT use duplicate GUIDs on interfaces

Posted by jpluimers on 2019/04/04

One of the things when fixing bugs in an old codebase is wading through technical debt.

A quick win is to get rid of duplicate GUIDs when interface portions have been copy-paste re-used:

  1. interfaces with the same GUID are treated the same with as casts even if they are different.
  2. the compiler does not warn about duplicate GUID values**

These searches help big time: it shows the duplicate GUIDs if they have been indented all the same way. Good enough for most situations.

grep -Sh "\[\'{" *.pas | sort

grep -rh "\[\'{" *.pas | sort

It depends which flavour of grep you use (gnu or regular) to specify recursion.

Note that findstr doesn’t cut it as it always shows the filename: [WayBack] List files recursively showing only full path and file size from Windows Command Prompt – Super User

** this compiles without warning:

program NoWarningOnDuplicateInterfaceGUID;

{$APPTYPE CONSOLE}

{$R *.res}

uses
  System.SysUtils;

type
  IInterface1 = interface
    ['{ECF26C39-CBFF-488E-A3AB-2629726F1005}']
  end;

  IInterface2 = interface
    ['{ECF26C39-CBFF-488E-A3AB-2629726F1005}']
  end;

var
  Subject: IInterface;
begin
  try
    (Subject as IInterface1)._Release;
    (Subject as IInterface2)._release;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
end.

–jeroen

Read the rest of this entry »

Posted in Delphi, Development, Software Development | Leave a Comment »

« Previous Entries
Next Entries »