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

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Archive for August 17th, 2021

Winbox 3.19 can connect via MAC whereas Winbox 3.17 cannot

Posted by jpluimers on 2021/08/17

Not sure why, but Winbox 3.17 could not connect to out of the box blank MikroTik equipment at all.

Winbox 3.19 complains every now and than, but usually connects fine.

This was while configuring a bunch of [WayBack] MikroTik Routers and Wireless – Products: CRS305-1G-4S+IN.

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Posted in Development, Internet, MikroTik, Power User, RouterOS, routers, Scripting, Software Development | Leave a Comment »

delphi – How to embed the MIDAS.DLL in the client executable – Stack Overflow

Posted by jpluimers on 2021/08/17

I hardly use the [WayBack] TClientDataSet Class any more, so every once in a while I bump into a legacy project that does.

Often that forgets provide a deployment list, so usually with deployment of the underlying DLL is forgotten.

Those moments, it slips my mind that the original name for the underlying DataSnap technology is called MIDAS, and the DLL is MIDAS.DLL. Sometimes even a wrong version of that DLL is distributed (unicode versus non-unicode still can still be a thing).

You can avoid loading it (often at a premium of reduced speed) my adding MidasLib to the uses list of any unit in your project:

When you use BPLs instead of full units, then missing this can lead to a nasty access violation like this one where the ClientDataSet cannot be created because the wrong Midas.dll (non-unicode) was loaded, see the screenshot and stack overflow below.

Lessons re-learned:

  1. Use a minimal deployment footprint
  2. Ensure your test systems are clean, so no older versions of dependencies can be loaded at any time.

OS EAccessViolation at adress 5110E007: Access violation at address 5110E007 in module 'dsnap250.bpl'. Read of address 00000000
{occured in main thread}

[50060B13]{rtl250.bpl  } System.@HandleAnyException
[00404815]{GVS.exe     } FastMM4.CalculateHeaderCheckSum$qqrp29Fastmm4.TFullDebugBlockHeader (Line 9098, "FastMM4.pas" + 1)
[50060039]{rtl250.bpl  } System.@AfterConstruction
[00404815]{GVS.exe     } FastMM4.CalculateHeaderCheckSum$qqrp29Fastmm4.TFullDebugBlockHeader (Line 9098, "FastMM4.pas" + 1)
[00404824]{GVS.exe     } FastMM4.UpdateHeaderAndFooterCheckSums$qqrp29Fastmm4.TFullDebugBlockHeader (Line 9108, "FastMM4.pas" + 1)
[004057C6]{GVS.exe     } FastMM4.DebugGetMem$qqri (Line 9649, "FastMM4.pas" + 42)
[00405817]{GVS.exe     } FastMM4.DebugGetMem$qqri (Line 9686, "FastMM4.pas" + 79)
[5005A247]{rtl250.bpl  } System.@ReallocMem
[50065674]{rtl250.bpl  } System.DynArraySetLength
[50065715]{rtl250.bpl  } System.@DynArraySetLength
[5110D001]{dsnap250.bpl} Datasnap.Dbclient.TCustomClientDataSet.CreateDSBase
[51111571]{dsnap250.bpl} Datasnap.Dbclient.TCustomClientDataSet.CreateDataSet
[500E920D]{rtl250.bpl  } System.Rtti.TValue._op_Implicit
[00559D29]{CDSDemo.exe } MainDataModuleUnit.TMainDataModule.DataModuleCreate (Line 50, "MainDataModuleUnit.pas" + 1)
[5016E7EF]{rtl250.bpl  } System.Classes.TDataModule.DoCreate
[5016E69C]{rtl250.bpl  } System.Classes.TDataModule.AfterConstruction
[50060039]{rtl250.bpl  } System.@AfterConstruction
[5016E67A]{rtl250.bpl  } System.Classes.TDataModule
[00544941]{CDSDemo.exe } MainFormUnit.TMainForm.PageControlChange (Line 30, "MainFormUnit.pas" + 19)
[0054598B]{CDSDemo.exe } MainFormUnit.TMainForm.FormShow (Line 40, "MainFormUnit.pas" + 47)
[50C075DD]{vcl250.bpl  } Vcl.Forms.TCustomForm.DoShow
[50C0BF7D]{vcl250.bpl  } Vcl.Forms.TCustomForm.CMShowingChanged
[5005FD9F]{rtl250.bpl  } System.TObject.Dispatch
[50AC4C16]{vcl250.bpl  } Vcl.Controls.TControl.WndProc
[50AC97FB]{vcl250.bpl  } Vcl.Controls.TWinControl.WndProc
[50C080B5]{vcl250.bpl  } Vcl.Forms.TCustomForm.WndProc
[50AC4850]{vcl250.bpl  } Vcl.Controls.TControl.Perform
[50AC8B71]{vcl250.bpl  } Vcl.Controls.TWinControl.UpdateShowing
[50AC8C80]{vcl250.bpl  } Vcl.Controls.TWinControl.UpdateControlState
[50ACB9D6]{vcl250.bpl  } Vcl.Controls.TWinControl.CMVisibleChanged
[50AC4C16]{vcl250.bpl  } Vcl.Controls.TControl.WndProc
[50AC97FB]{vcl250.bpl  } Vcl.Controls.TWinControl.WndProc
[50C080B5]{vcl250.bpl  } Vcl.Forms.TCustomForm.WndProc
[50C0E597]{vcl250.bpl  } Vcl.Forms.TScreen.GetMonitor
[50C094C5]{vcl250.bpl  } Vcl.Forms.TCustomForm.SetWindowToMonitor
[50AC4850]{vcl250.bpl  } Vcl.Controls.TControl.Perform
[50AC31E6]{vcl250.bpl  } Vcl.Controls.TControl.SetVisible
[50C078C1]{vcl250.bpl  } Vcl.Forms.TCustomForm.SetVisible
[50C11DCF]{vcl250.bpl  } Vcl.Forms.TApplication.Run
[004B3B28]{CDSDemo.exe } VclApplication.TApplication.Run (Line 113, "VclApplication.pas" + 1)
(00161097){CDSDemo.exe } [00562097]


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

Yet again, GitHub violates the Web Content Accessibility Guidelines by stealing a key: not it is the dot (.)

Posted by jpluimers on 2021/08/17

More sites seem to have a tendency of stealing keyboard shortcuts and violating the WCGA (Web Content Accessibility Guidelines), especially the (lowest!) conformance level A in [Wayback] WCAG version 2.1, section Success Criterion 2.1.4 Character Key Shortcuts

If a keyboard shortcut is implemented in content using only letter (including upper- and lower-case letters), punctuation, number, or symbol characters, then at least one of the following is true:

1. Turn off
mechanism is available to turn the shortcut off;
2. Remap
A mechanism is available to remap the shortcut to use one or more non-printable keyboard characters (e.g. Ctrl, Alt, etc);
3. Active only on focus
The keyboard shortcut for a user interface component is only active when that component has focus.

Mind you, I’m a keyboard person, there is even a: Keyboards and Keyboard Shortcuts category, but they always need to be configurable, anything else is a sin.

And GitHub did it again: [] GitHub on Twitter: “🤫 New shortcut: Press . on any GitHub repo.… “.

So I’m totally with these:

Now they have started to steal the dot (.) keyboard to (in-place, with a fully new URL and no indication how to easily go back) start Visual Studio Code in the current repository.

Going back, though not documented, actually takes between one and three “back” movements in your web-browser history: utterly ridiculous for a key one can accidentally hit.

This behaviour violates all three above sub-criterions:

  1. it cannot be turned off
  2. there is no way to remap it
  3. it is almost always activated (unless there a text input – like “search” or “goto file” – has focus)

This is a very bad way to cope with accessibility, especially as conformance level A is yet again violated.

[Wayback] WCAG 2.1: section 5.2.1 Conformance Level:

One of the following levels of conformance is met in full.

  • For Level A conformance (the minimum level of conformance), the Web page satisfies all the Level A Success Criteria, or a conforming alternate version is provided.
  • For Level AA conformance, the Web page satisfies all the Level A and Level AA Success Criteria, or a Level AA conforming alternate version is provided.
  • For Level AAA conformance, the Web page satisfies all the Level A, Level AA and Level AAA Success Criteria, or a Level AAA conforming alternate version is provided.

To me another cardinal sin is that they stole Ctrl-F / Command-F (depending if you use non-MacOS or MacOS) from the web browser. So now it does not find it in the full page, but only in the currently selected file. (You guessed it, I’m with [] KewlCat on Twitter: “I hate it when they intercept “/” and even [Ctrl]-F… “ too)

More of those conformance violation sins are at [Wayback] Keyboard shortcuts – GitHub Docs.

It isn’t hard to prevent this kind of thinking: it’s a mind set as described by [] Patrick Joannisse on Twitter: “I don’t know if you are expecting a real answer but here goes: it starts with the mindset. In my training they had us wear goggles to block our vision and made us use a screen reader for a while. We met people with disabilities and they would show us how they work.… “

If you still like it and want to know how it works


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Posted in accessibility (a11y), Development, GitHub, Keyboards and Keyboard Shortcuts, Power User, Software Development, Source Code Management | Leave a Comment »

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