In my opinion, threading code needs to be written and maintained by people that live and breath multi-threading. Over the years, RTL and TPL have not lived up to that, but a library like [WayBack] OmniThreadLibrary has.
Slim Reader/Writer Lock (SWRL) is even faster than TMonitor:
CriticalSection 0.035
TMonitor 0.019
SWRL 0.012
Of course if you have a speedy lock-free solution, that is always favourable, but few people know how to write lock free data structures or how to find the libraries (despite Julian Bucknall covering quite a few of them in Delphi back in the days).
For Variant types, the = comparison operator in Delphi maps to the VarCompareValue in the Variants unit.
That function fails to handle various comparisons and for some it knows it can handle raises a VarInvalidOp through various code paths (like CheckType) to VarInvalidOp because the implementation limits itself to varEmpty..varUInt64, which I think means that these are unsupported:
varRecord
varStrArg
varObject
varUStrArg
varString
varAny
varUString
varArray
varByRef
This fails when using the = operator:
What is this code supposed to do, if v1 and v2 are variant arrays with the same content?
if v1 = v2 then
WriteLn('equal')
else
WriteLn('not equal');
Thomas basically did all the research on the forwarding needed for ELC (formerly Belise/Elise), then showed the PuTTY equivalent to ssh user@remote -L5567:192.168.1.200:5567:
When writing this, the above links got me the below list. For consistency (as you cannot save URLs for prior versions in the WayBack machine because a brain-dead robots.txt setting which archive.is luckily ignores):
Delphi does indeed so some type inference as Primoz found out below. It has been doing this for a long time, improved over time, but has a long road ahead.
This is a reminder to myself to write some more example code on what kinds of inference work and which do not, especially because of the comments from David Heffernan, Marco Cantu and Stefan Glienke, especially since the improvement over time has been small. I am curious to see how the promised “working on it” by now lives up to reality.
David Heffernan
This is a rare piece of code where type inference actually works. Mostly it does not which is very frustrating.
It’s a little ironic that you ask why you don’t need to include <T>. Normally people ask about the much more frequent instances where you do need to include <T> because the compiler’s type inference is so weak.
David Heffernan
+Marco Cantù Much more commonly there are times when you want the compiler to infer the type, but it won’t. It would really make a difference to us if the compiler was better at this.
Marco Cantù
+David Heffernan I tend to agree the compiler should be much better at type inference. Working on it!
Stefan Glienke
Infering the generic argument from a constructed generic type would be great.
GuessTheType<T>(const x: TArray<T>);
var
a: TArray<Integer>;
begin
GuessTheType(a);
does not work although the compiler could infer the parameter for GuessTheType from its x parameter but currently it does not know that a originally was a TArray<T> (yes, I know array of T as signature works but that is a different thing).
P.S. +Marco Cantù btw how hard can it be to finally implement generic standalone routines without that ugly static type? Probably one of the highest voted feature requests: https://quality.embarcadero.com/browse/RSP-13724)
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Warning: I posted this without doing a proper copyright check on the linked github repository, and it looks like this library heavily copies code from copyrighted materials.
So better not use them, for one because they contain copyrighted material, and also because the copyrighted units are not current.
At least these units are Copyright by Embarcadero:
Androidapi.JNI.Environment.pas:4:{ Copyright(c) 2014 Embarcadero Technologies, Inc. }
Better_JSON.pas:5:{ Copyright(c) 2016 Embarcadero Technologies, Inc. }
Bluetoothcomponentthreaded.pas:4:{ Copyright(c) 2016 Embarcadero Technologies, Inc. }
FMX.Better.Controls.pas:5:{ Copyright(c) 2011-2013 Embarcadero Technologies, Inc. }
FMX.Better.ListBox.pas:5:{ Copyright(c) 2011-2013 Embarcadero Technologies, Inc. }
Generics.Collections.Fixed.pas:5:{ Copyright(c) 1995-2014 Embarcadero Technologies, Inc. }
HTTPClient_2019.pas:6:{ Copyright(c) 1995-2018 Embarcadero Technologies, Inc. }
InetWinSocketReg.pas:5:{ Copyright(c) 1995-2012 Embarcadero Technologies, Inc. }
pngimage_fmx.pas:5:{ Copyright(c) 1995-2014 Embarcadero Technologies, Inc. }
SocketsEditor.pas:5:{ Copyright(c) 1995-2012 Embarcadero Technologies, Inc. }
The Wiert Corner - irregular stream of stuff 