Posted by jpluimers on 2019/04/03
Reminder to self: [WayBack] It took me a while to address an awful IDE crash issue. If you install a design time package which uses RTTI to populate custom attributes declared in… – Baoquan Zuo – Google+
TL;DR: be very careful using the built-in RTTI support objects as when they refer to custom defined attributes in packages, and the packages get unloaded, the cache does not get flushed.
–jeroen
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Posted by jpluimers on 2019/04/02
Boy I wish that QC was still up and QualityPortal was publicly indexable as that would have saved me quite a bit of time tracking this down. Luckily I got help from Stefan Glienke (who maintains the awesome Spring4D library based on modern Delphi compiler support) when I mentioned
How good are you with reference to function?
I’ve an odd compiler thing throwing errors when using interfaces but not with classes.
So, for posterity:
Unlike C#, in Delphi interface methods are not compatible with method references or methods of object.
This has many manifestations, which means you can get a variety of compiler errors. I’ve listed the ones I could find below, but presume there are more and if I find more will update this post.
These are the errors you can get:
These are the (now defunct, but used to be publicly accessible) QC and QualityPortal (needs sign on) entries (thanks Stefan Glienke and Blaise Thorn for reporting these):
The really frustrating part is that the RSP is marked as “new feature” whereas clearly it isn’t, so it probably never will be fixed.
A workaround for now is to wrap the interface method references with:
Examples are in the code below that also shows this works fine and dandy in C#.
–jeroen
Posted in Delphi, Delphi 10 Seattle, Delphi 10.1 Berlin (BigBen), Delphi 10.2 Tokyo (Godzilla), Delphi XE3, Delphi XE4, Delphi XE5, Delphi XE6, Delphi XE7, Delphi XE8, Development, Software Development, Spring4D | Leave a Comment »
Posted by jpluimers on 2019/03/28
On my research list: Not sure why, but sometimes the Delphi options display a regular application, but the IsConsole returns true because of AppType Console in the main PropertyGroup.
initialization section of the System unit
One of the problems is that unlike the {$APPTYPE directive (which has not changed much over time), the AppType element is undocumented (hardly anything in the .dproj file is documented).
The $APPTYPE lists two values: Console and GUI, defaulting to GUI:
Empirically, the AppType element can have these values:
ApplicationConsolePackageThis is the topmost part of the .dproj file does not matter, without AppType element valued Console, or with it or even having it valued Application: either way a console application is being built.
There is no $APPTYPE in the .dpr or any of the .pas files.
The IsConsole variable is always false and a console window always appears when debugging.
That variable is not always conclusive, as there are situations where code is inside a BPL or DLL started by an EXE, so this works better: [WayBack] How to determine if I’m running as a console app? (Delphi on Win32) – Stack Overflow:
function IAmAConsoleApp: Boolean; var Stdout: THandle; begin Stdout := GetStdHandle(Std_Output_Handle); Win32Check(Stdout <> Invalid_Handle_Value); Result := Stdout <> 0; end;
The .dproj files:
Posted in Delphi, Development, Software Development | 2 Comments »
Posted by jpluimers on 2019/03/28
An interesting read on Windows Manifest Files in Delphi [WayBack].
Do not let Delphi manage your manifest. All versions are either limited, or buggy, or both.
Basically it’s the same as doing VersionInfo in Delphi: do not let the IDE do it, but do it yourself. In this case:
Write your own manifest in XML, then load it as a resource.
Via: [WayBack] Blogged : Windows Manifest Files – In this post I look at Windows Manifest Files, what they do, why we need them and how to use them in Delphi and Finalbuilder… – Vincent Parrett – Google+
–jeroen
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Posted by jpluimers on 2019/03/27
The list below is based on a G+ discussion in a single language, but has way broader aspects.
It’s on value types, mutability, parameterless constructors and expectations of compiled code.
I’ve bitten myself in the foot with mutable types in too many languages too often, so I started advocating this years ago at clients, and now in this blog-post.
TL;DR:
Posted in .NET, C#, C++, Delphi, Development, Jon Skeet, Software Development | 2 Comments »
Posted by jpluimers on 2019/03/27
When I ever go and use the Spring4D activator, these are some URLs I need to re-read:
IInvokable over IInterface to enfore using RTTI [Archive.is] The Dynamic Abstract Factory is so useful but it’s like magic to me! – Google Groups
–jeroen
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Posted by jpluimers on 2019/03/19
Odd, the [WayBack/Archive.is] Delphi Intrinsic Routines – RAD Studio indicates quite a few compiler intrinsics are not available on Windows.
I wonder if this list is correct:
Routine Description DCC32 DCC64 DCCOSX DCCAARM DCCIOSARM DCCIOSARM64 DCCIOS32 System.AtomicCmpExchange AtomicCmpExchange is used for comparing and exchanging memory values. System.AtomicDecrement AtomicDecrement is used for decrementing memory values. System.AtomicExchange AtomicExchange is used for exchanging memory values. System.AtomicIncrement AtomicIncrement is used for incrementing memory values. System.BuiltInArcTan Calculates the arctangent of a given number. System.BuiltInArcTan2 Calculates the arctangent angle and quadrant of a given number. System.BuiltInCos Calculates the cosine of an angle. System.BuiltInLn Calculates the natural logarithm of a real expression. System.BuiltInLnXPlus1 Calculates the natural logarithm of (X+1). System.BuiltInLog10 Calculates log base 10. System.BuiltInLog2 Calculates log base 2. System.BuiltInSin Calculates the sine of the angle. System.BuiltInSqrt Calculates the square root of X. System.BuiltInTan Calculates the tangent of X.
Especially since this compiles fine with the DCC32 compiler:
program CompilerIntrinsicsConsoleProject; {$APPTYPE CONSOLE} {$R *.res} var I, J, K: Integer; begin System.AtomicCmpExchange(I, J, K); System.AtomicDecrement(I); System.AtomicExchange(I, J); System.AtomicIncrement(J); end.
–jeroen
Posted in Delphi, Delphi 10.3 Rio (Carnival), Development, Software Development | 3 Comments »
Posted by jpluimers on 2019/03/14
From a while ago [WayBack] delphi – Why was TDataSource created originally? – Stack Overflow
It is all about decoupling and indirection.
And with TDataSource there are two kinds of them:
- Decoupling the master detail relations (TDataSource is in the same module as the TDataSets that are being bound; the detail TDataSet references the master TDataSet by pointing its’ MasterSource property to the TDataSource that points to the master TDataSet)
- Decoupling the UI from the business layer (TDataSets are in a DataModule; TDataSource is on the Form/Frame which contains your UI controls, UI controls reference their DataSourceproperty).
Since many components can point to the same DataSource, you can quickly switch which underlying TDataSet they use by just flipping one TDataSource.DataSet property.
–jeroen
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Posted by jpluimers on 2019/03/12
For my link archige: [WayBack] Classic compiler (Win32) strings double-free crash because of error in reference-counting. Tested with XE2 and 10.1 Berlin Test applications: https://g… – Arioch The – Google+
–jeroen
Posted in Delphi, Development, Software Development | 3 Comments »
Posted by jpluimers on 2019/03/12
On my list of things to install soon IDE Fix Pack 6.4 and 6.4.1:
Technically, there is 6.4 that works in Delphi 10.3 Rio Update 1, but it is better to install 6.4.1 as it works with 10.3 and 10.3.1:
The dependencies file looks interesting for good uses list optimisation, given that you compile with all conditional define permutations:
There is a ton of changes, of which I like the bold ones most:
–jeroen
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The Wiert Corner - irregular stream of stuff 