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Lars Fosdal

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Everything posted by Lars Fosdal

  1. Lars Fosdal

    TTimer equivalent with smaller interval

    Anyways - under Windows, we have the so-called multimedia timer, https://docs.microsoft.com/en-us/windows/win32/multimedia/about-multimedia-timers but a caveat is that actual minimum resolution varies with platform and device https://docs.microsoft.com/en-us/windows/win32/multimedia/timer-resolution var TCaps: TTimeCaps; // WinAPI.MMSystem; rc: MMResult; begin rc := timeGetDevCaps(@TCaps, SizeOf(TCaps)); // WinAPI.MMSystem; if rc = 0 then Writeln(Format('Min %d / Max %d', [TCaps.wPeriodMin, TCaps.wPeriodMax])) else Writeln(Format('timeGetDevCaps returned %d', [rc])); end; outputs Min 1 / Max 1000000 on my computer. Oddly enough, the resolution is 1ms - so, in theory it is impossible to use a timer to get a better resolution than 1 ms. Still - the WaitableTimer has 100ns resolution, so that should work, right? https://docs.microsoft.com/en-gb/windows/win32/api/synchapi/nf-synchapi-setwaitabletimer function NanoSleep(const NanoSec: Int64):Boolean; var Timer: THandle; Constraint: _Large_Integer; begin Result := False; Timer := CreateWaitableTimer(nil, True, nil); if timer <> 0 then try Constraint.QuadPart := -NanoSec; if SetWaitableTimer(Timer, Constraint.QuadPart, 0, nil, nil, False) then begin WaitForSingleObject(Timer, INFINITE); Result := True; end; finally CloseHandle(Timer); end; end; but even that is incredibly erratic. const ns: Int64 = 10000; var st: TStopWatch; ix: Integer; begin st := TStopWatch.StartNew; for ix := 1 to 10 do NanoSleep(ns); st.Stop; Writeln(st.ElapsedMilliseconds); end; and does not seem to work at low intervals - unless I screwed something up? Windows is not a real time OS - so it seems milliscond timing will be iffy - unless you use a power consuming loop of instructions - and that is not desirable.
  2. Lars Fosdal

    TTimer equivalent with smaller interval

    I am curious - when would you need such minuscule intervals?
  3. Lars Fosdal

    custom attributes question

    TRttiType.GetProperties.GetAttributes vs TRttiType.GetFields.GetAttributes Personally, I've avoided setting props on fields and only set them on properties. There are parts of the RTL where the opposite applies - f.x. for REST.JsonReflect, which checks the fields and not the properties.
  4. Lars Fosdal

    class designation question

    Guilty. Like OOP, Generics are sooo addictive!
  5. Lars Fosdal

    TTimer equivalent with smaller interval

    My first thought was - why not use a thread with sleep if you need that fast a timer - but - again, multithreading raises its own issues.
  6. What about the theory that dictionaries have fewer collisions if you set the capacity to be a prime number ? Fact or fiction? Personally, I do actually set the capacity to a prime, but I am not quite sure if it because it is sound advice or if it is a cargo cult thing. Edit: Funny enough, @Tommi Prami posted an alternative approach.
  7. Less readable code can be greatly alleviated with decent commentary. Document general intent and method rather than say what each line does.
  8. Empirically proven to work. "Awful" can be - slow code, albeit in a context where performance is not required - cryptic code - code that could be simplified with modern RTL code Anyways - Refactor when you need to, and not just because you'd like to - unless unlike most devs, you have time to spare. Oh - as @Stefan Glienkesuggests: Make sure you have the tests to validate your refactoring.
  9. Another challenge is knowing when NOT to refactor. "This code works, but it looks awful... should I refactor?"
  10. Since threading is non-trivial, it is hard to make examples that are not either non-trivial or oversimplified. You may find yourself writing quite a bit of scaffolding code, which would have come for free with OTL.
  11. What are your needs / goals?
  12. Lars Fosdal

    Running commandline app and capturing output

    Is the behavior erratic across multiple executions of the same application - or is it specific applications that do not let you capture?
  13. Lars Fosdal

    With haters unite

    True, but the point is a more natural limit of variable scope. var ref := Some.Array[Index1].Reference; var thing := Function(Index1).Thing; if ref.Value <> thing.Value then begin ... end; // ref and thing ARE present here I guess you could wrap it in another pair of begin/end - but that would look a bit strange, while the with signals clearly that these are local.
  14. Lars Fosdal

    With haters unite

    I'd like this to be possible, and a compiler switch that bans the old with statements. with var ref := Some.Array[Index1].Reference, var thing := Function(Index1).Thing do begin if ref.Value <> thing.Value then begin ... end; end; // ref and thing are not present
  15. Lars Fosdal

    With haters unite

    Did you mean https://quality.embarcadero.com/browse/RSP-18953 - Tommi? 21814 is the Windows 10 Ansi/UTF-8 QP - which, by the way, returns different values on my Windows 10 Enterprise 1809 10.0.17763.831, depending on which PowerShell version you use. PowerShell 5.1 IsSingleByte : True BodyName : iso-8859-1 EncodingName : Western European (Windows) HeaderName : Windows-1252 WebName : Windows-1252 WindowsCodePage : 1252 IsBrowserDisplay : True IsBrowserSave : True IsMailNewsDisplay : True IsMailNewsSave : True EncoderFallback : System.Text.InternalEncoderBestFitFallback DecoderFallback : System.Text.InternalDecoderBestFitFallback IsReadOnly : True CodePage : 1252 PowerShell 6.2.4 Preamble : BodyName : utf-8 EncodingName : Unicode (UTF-8) HeaderName : utf-8 WebName : utf-8 WindowsCodePage : 1200 IsBrowserDisplay : True IsBrowserSave : True IsMailNewsDisplay : True IsMailNewsSave : True IsSingleByte : False EncoderFallback : System.Text.EncoderReplacementFallback DecoderFallback : System.Text.DecoderReplacementFallback IsReadOnly : True CodePage : 65001
  16. What are the odds that FMX in Rio uses something that is not present in SdkVersion 14?
  17. Lars Fosdal

    How to make app with tabbed set of VNC windows

    In that case, Remote Desktop Manager is the way to go.
  18. Lars Fosdal

    SHA Extensions and Delphi

    Would it be possible to wrap the assembly versions of these in Delphi? https://www.nayuki.io/page/fast-sha2-hashes-in-x86-assembly
  19. Lars Fosdal

    How to make app with tabbed set of VNC windows

    If the need is simply parallel remote control like starting/stopping scripts/apps or services - you would do much better by using PowerShell.
  20. Lars Fosdal

    How to make app with tabbed set of VNC windows

    @David Schwartz Have you guys tried https://remotedesktopmanager.com/ ? It is freaking awesome for managing a large server park! We have literally hundreds of servers and would be lost without it. It supports pretty much every remoting protocol you can think of: https://remotedesktopmanager.com/features/remote-connection-management You can have the windows tabbed, cascaded, tiled vertically or horizontally. You can lock the Windows hotkeys so that you have to use the mouse to get out of the context of the remote view. I.e. Alt-Tab happens within the focused remote connection. There is a free version for personal use, but if you have a team, you want the enterprise version.
  21. Lars Fosdal

    Custom TrueType font in FMX Android app?

    Do all of them involve creating a modified FMX.FontGlyphs.Android.pas !? Is there a QP I can vote for to improve this somehow?
  22. Lars Fosdal

    Overloaded generic methods

    Must it be an overload? Why not FindComponentsByClass vs FindComponentsWithInterface ?
  23. Lars Fosdal

    Detect user location from ip address

    It is a joke - implying that if you surf from the space station, you get dating ads that are "near you" as spammers often use geolocation to generate fake ads for offers in your area.
  24. Lars Fosdal

    Detect user location from ip address

    Geolocation from IP address: https://www.iplocation.net/ip-address
  25. Lars Fosdal

    What are your compiler settings for debug builds?

    Same as @dummzeuch We also leave range checks on for release versions. For us, API and database access times dwarf the array access times, and there is nothing quite like live data to throw curveballs at your algorithms.
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