Archive for the ‘Delphi’ Category
Posted by jpluimers on 2017/11/30
Note that the below solution works for any project raising the W1029 warning (not just from projects using Delphi Mocks) like
[dcc32 Warning] W1029 Duplicate constructor 'ClassName.ConstructorName' with identical parameters will be inacessible from C++
From my original text at [WayBack] Get rid of W1029 warning in Delphi compile mode · Issue #106 · VSoftTechnologies/Delphi-Mocks · GitHub:
By default the compiler will emit warnings like these for projects when using either of the Delphi.Mocks.Behavior or Delphi.Mocks.Expectation directly or indirectly:
[dcc32 Warning] W1029 Duplicate constructor 'TExpectation.CreateOnceWhen' with identical parameters will be inacessible from C++
They’re harmless as DUnitX doesn’t support C++. This particular warning type cannot be disabled on the unit or source line level which means you have to disable it on the project level by either:
- adding
{$WARN DUPLICATE_CTOR_DTOR OFF} anywhere to your .dpr project file
- modifying the the Project Options for your project (easiest is in the
All configurations - All platforms target):
- follow the path
Delphi Compiler, Hints and Warnings in the treeview on the left
- expand the
Output warnings node in the listview on the right
- set
Duplicate constructor/destructor with identical parameters will be inacessible from C++ to Error
A screenshot of the second option is below.
Note that the spelling mistake in Duplicate constructor/destructor with identical parameters will be inacessible from C++ is how it is in the IDE, but that as Google search string it will give limited results, so here are some back-ground references:
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Posted in Delphi, Delphi 10 Seattle, Delphi 10.1 Berlin (BigBen), Delphi 2007, Delphi 2009, Delphi 2010, Delphi XE, Delphi XE2, Delphi XE3, Delphi XE4, Delphi XE5, Delphi XE6, Delphi XE7, Delphi XE8, Development, Software Development | Leave a Comment »
Posted by jpluimers on 2017/11/29
Though I try to refrain from using the singleton pattern when possible (I prefer dependency injection over accessing “globals” that usually tend up to be not so global after all), sometimes I need to.
In C# there has been a canonical singleton pattern implementation by John Skeet for a very long time at [WayBack] C# in Depth: Implementing the Singleton Pattern.
I just found out there has been similar implementations in Delphi both in this question (which like many useful questions is marked “closed”, oh the joy of StackOverflow): [WayBack] “Delphi Singleton Pattern – Stack Overflow:
I like both implmentation, but usually take the first as mostly locking has little overhead and sometimes two instances cannot co-exist (though that’s lessened when part of the singleton uses lazy initialisation, for instance from Spring4D).
–jeroen
via: [WayBack] May I please ask for your opinion on the following code:..singleton… – John Kouraklis – Google+
Posted in Delphi, Development, Software Development | Leave a Comment »
Posted by jpluimers on 2017/11/29
Sometimes the title of a G+ entry looks not so interesting, but then you read the comments. In this cast it’s about the mediator pattern support in the tiOPF object persistence framework, how it works very well from Free Pascal and both classic and modern Delphi compilers and why developers dislike ARC. It’s cool as it allows you to decouple UI from business logic and separate out business logic from your application into a back-end. Recommended reading: [WayBack] Hello i have a program that use MS SQL SERVER 2000i want to make a mobile application that connect to this database to make some consultationclient fi… – Mohammed Bouhlal – Google+
–jeroen
Posted in Delphi, Development, FreePascal, Pascal, Software Development | Leave a Comment »
Posted by jpluimers on 2017/11/28
I think it was Stefan Glienke who pointed me at the Memoisation pattern: [WayBack] Implementing Memoize in Delphi 2009 – Community Blogs – Embarcadero Community
Or in laymans terms: caching with generic functions and dictionaries.
Note the Archive.is link is way better readable than the WayBack link, so below I’ve saved parts only in Archive.is.
It points to two other interesting reads:
Later I found it was indeed Stefan who pointed me to the above links and also came up with this very small Memoisation example which is based on Spring4D:
and guess what? because we have interfaced based dictionary this is super easy, let me just hack an example, 5mins6:52 PM
function BuildCache: Tfunc<string,string>;
var
cache: IDictionary<string,string>;
begin
cache := TCollections.CreateDictionary<string,string>;
Result :=
function(s: string): string
begin
if not cache.TryGetValue(s, Result) then
begin
Sleep(1000); // hard work! ;)
Result := ReverseString(s);
cache.Add(s, Result);
end;
end;
end;
Since the returned anonymous method captures the dictionary its kept inside and once the anonymous method goes out of scope the dictionary is also cleaned, want to reset the cache? Just create a new one and throw the old one away.
Need thread safety? just add
System.TMonitoy.Enter/Leave(cache.AsObject);
–jeroen
Posted in Delphi, Development, Software Development | Leave a Comment »
Posted by jpluimers on 2017/11/23
[WayBack] Use operator overloading for classes with non-ARC compiler · GitHub
The trick: do not use class operator but use class function &&op_ with the special operator name in the table referenced below. Just follow the bulleted example links to get an idea.
Bonus: it works on class helper constructs as well.
Officially this unsupported and with the non-ARC compiler you will have a risk of memory leaks.
But it’s so much fun as these links prove:
The usual operator gotchas apply here as well: Delphi operator overloading: table of operators, names, and some notes on usage and ‘glitches’.
The operators you could try: [WayBack] Operator Overloading (Delphi) – RAD Studio
Oh, this thread needs some change now: [WayBack] List of Delphi language features and version in which they were introduced/deprecated – Stack Overflow
–jeroen
Posted in Delphi, Development, Software Development | 1 Comment »
Posted by jpluimers on 2017/11/22
Thanks Uwe for the below code!
I was in a situation of a batch file running from a Task Scheduler that got broken because the user suddenly turned on persistent network connections.
So I needed to check if a shared drive-letter was indeed persistent or not and act accordingly.
The below code helped me merging the batch file with the Delphi application it would run in the background anyway.
It’s way better than checking of the global “persistence” flag for new connections has been set in the registry: [WayBack] SaveConnections flag at HKCU\Software\Microsoft\Windows NT\CurrentVersion\Network\Persistent Connections (which is reflected both in the Windows UI and settable via net use /Persistent).
Source: check if network connection is permanent
Via: [WayBack] Anyone who can share how one can query if a drive letter mapping to a share is persistent across logon sessions? (yes, this is Windows, I know) – Jeroen Wiert Pluimers – Google+
–jeroen
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Posted in Delphi, Development, Software Development | Leave a Comment »
Posted by jpluimers on 2017/11/21
A post of some older Delphi stuff I did in the past just in case need it again.
David Heffernan found the documentation for this: [WayBack] Structured Types (Delphi): Dynamic Arrays – RAD Studio
Since I needed a dynamic array structure supporting a non-zero lower bound, I was glad he also provided an answer with a data structure that does provide a non-zero lower bound.
For my own reference I’ve put his answers and questions below (as it’s way easier to search my blog than the complete internet) and my own implementation:
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Posted in Delphi, Development, History, Software Development | 10 Comments »
Posted by jpluimers on 2017/11/16
For my link archive:
Some quotes
–jeroen
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Posted by jpluimers on 2017/11/15
This is why you should always test your Delphi apps with FastMM4 and FullDebugMode enabled: [WayBack] Delphi – Recompiling application with 10.2.1 causes memory leaks?
A workaround is to add the below code in either of these places:
- end of your
.dpr file right before the end.
- in the
finalization section of a new unit
CheckSynchronize();
It calls the [WayBack] System.Classes.CheckSynchronize method to ensure the background thread performs the needed cleanup.
Thanks Stefan Glienke for solving this.
–jeroen
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Posted in Delphi, Delphi 10.2 Tokyo (Godzilla), Development, Software Development | Leave a Comment »
The Wiert Corner - irregular stream of stuff 