Dave Novo

@David Heffernan - I do check for errors when writing to files, databases other "external" places I am writing the data. In that case, who knows what is going on and what could have happened to the file/database connection. However, when writing to a memory stream, would you really advocate the code below? It is unnecessarily verbose, all to handle an out of memory error, which would crush my program anyhow and not easy to recover from. What other error would I be worried about here that I could realistically handle and recover from. var m:TMemoryStream; r:TRect; p:TPoint; value:integer; cntr: Integer; curVal: Integer; bytesWritten:integer; begin m:=TMemoryStream.Create; // initialize r,p, curVal with some data bytesWritten:=m.writeData(r,sizeof(r)); if bytesWritten<>sizeof(r) then raise exception('error writing r'); bytesWritten:=m.writeData(p,sizeof(p)); if bytesWritten<>sizeof(p) then raise exception('error writing p'); bytesWritten:=m.writeData(curVal,sizeof(curVal)); if bytesWritten<>sizeof(curVal) then raise exception('error writing curVal'); .... rest of the method here. m.Free; end;

That seems to be it. Turning TYPEADDRESS ON in Seattle gives the same compiler error.

The following code works perfectly in Delphi Seattle? Just luck??? var m:TMemoryStream; r:TRect; cntr: Integer; curVal: Integer; begin m:=TMemoryStream.Create; r.Left:=100; r.Top:=200; r.right:=300; r.bottom:=400; m.write(@r,sizeof(r)); m.position:=0; for cntr := 0 to 3 do begin m.Read(curVal,sizeof(integer)); showmessage(curVal.toString); end; m.Free; end; curVal.ToString reports 100, 200, 300, 400

hmm. We fixed a similar issue by doing procedure TForm1.Button1Click(Sender: TObject); var m: TMemoryStream; r: TRect; rectPtr:Pointer; begin m := TMemoryStream.Create; rectPtr:=@r; m.Write(rectPtr, sizeof(r)); // (@r, sizeof(r)); m.Free; end; I really should triple check that is working as expected.

De Novo Software is based on Pasadena, CA. If you happen to be in the area we can accommodate an onsite employee (remote until COVID is resolved) but we will also accept a fully remote position for the right candidate. Details are at https://denovosoftware.com/about-us/careers/software-developer/. We are a team of expert Delphi developers who love Delphi and have put together a cutting edge application used by scientists for state of the art research and clinicians around the world to diagnose many types of cancers and other diseases.

@Nigel Thomas - thanks!

In the situation where you have infinite time, and infinite resources, sure, the above statement is true. Most of us are not in that situation. If you want to simply answer, what is a bottleneck, that is easy... some single (or few) part of your program that throttles the entire execution path. The more difficult question is which bottleneck is worth investigating and fixing. For example, lets say you have some truly awful code in one part of the program that is causing something that should take 5 seconds to take 5 minutes. Really bad. But because of how your end users use the program, only 1% of people encounter this bottleneck. And those people all run that part of the program overnight anyhow, as part of a larger batch run. Is this even worth "looking into"? Maybe, if the "looking into" takes 10 minutes. Maybe not if the "looking into" takes a day. That is a day you are taking away from adding features, or fixing bug that affect the other 99% of your customers. How does your answer change if the bottleneck is such that something that should take 5 seconds takes 12 seconds? IMO, software development is not hard and doesn't fail usually because of programming challenges. i.e. how to code the algorithm, how to add the function. Software Development is hard because it requires choices like the one described above, to which there is no clear cut answer than anyone can give you that applies to all cases. Most coders can figure out how to write whatever SQL query you need and design a database that works. Successful projects / developers / teams consistently come up with the right answers to the more difficult questions like: what refactorings are worth the time it takes to do them? what level of "engineering" (when are you over-engineering, when are you under-engineering) is appropriate for the task I am doing? Which bugs are worth fixing? How to fix them (quick hack or deep rearchitecturing)? All of those questions are easy when you have nothing else to do, but usually that is not the case.

As a developer improves, (hopefully) the developer can write more optimized code in about the same amount of time as they used to write less optimized code. Knowing when to use a TStringBuilder instead of concatenating strings for example, and knowing when doing so will make a difference. Recognizing the use cases and intuitively selecting the data structure most suited for it. etc. Often, it does not take much longer to write faster code than slower code, if you know what you are doing. Beyond that, I would not do much optimization until you had specific use cases that were performing badly. Then, you need to profile those use cases. Once those have been profiled, sometimes it is obvious what to tackle, sometimes sadly its death by 1000 cuts. But I do not not think premature optimization is BS. It happens all the time and is generally a waste. Until you have specific use cases it does not make much sense to make much efforts to optimize, beyond what you are naturally able to do based on your skill level. You can spend hours optimizing some data structure that was never going to be a problem in the first place.

The other issue I have with .Tag is that once things get complex, it is hard to know who is (ab)using the Tag property for what. You have a brilliant idea to use the .Tag of some object to associate it with another object only to find out 3 weeks and 20 hard to reproduce crashes later that someone else is also using the .Tag under certain rare circumstances for other associations. Having explicit lists to hold different types of associations eliminates those problems. If you get in the habit of using .Tag all the time, you cannot even do a search for .Tag to see who is using the .Tag of your object because the search hits so many times. We used to use .Tag quite a bit but moved away from it primarily for that reason. If its a class that we control, we will make a property just for the association, that is appropriately named. If it is a class from a 3rd party library we make a list like @A.M. Hoornweg suggested. Of course, that is just our preference based on our personal experience. Your mileage may vary.

Hello, We are using Delphi Seattle. We have a ~ 2M LOC program with hundreds of units. The 64 bit compiler is running out of memory when compiling. Even when we set to "use MSBuild" to compile in a separate process. The separate process dies with an out of memory around 2GB of RAM usage. The VM I am using has 8 GB of RAM and plenty of spare RAM when the process dies. Aside from breaking the application into different packages/projects, does anyone have any bright ideas. We are in the process of upgrading to Delphi 10.4.1. Is the 64 bit compiler still a 32 bit app?

@Uwe Raabe - thanks for the tip. Everything works great after using the config settings you suggested.

The arm M1 has an emulator https://www.computerworld.com/article/3597949/everything-you-need-to-know-about-rosetta-2-on-apple-silicon-macs.html

@Uwe Raabe - thank you for the tool. After I made it compile for Delphi I ran it, and all it seemed to do was rearrange my uses clause. An example If the unit did have the fully qualified name, it moved them to the top of the uses clause, but otherwise left things alone. i.e. Am I missing something to make it prefix the fully qualified namespaces?

@Lajos Juhász - we definately are missing the unit scope names. I did not think that would make such a big difference. Certainly easy (but tedious) to fix.

@Fr0sT.Brutal - do you have an example of how you can feed python with the pointer to the delphi array and then use this data in Python?

Hi David, Thanks for the responses. The issue is that we already have a few 100 Mb TArray<Double> already allocated on the Delphi side. We want the user to be able to access that data on the python side without making a copy. ideally, somehow tell the python structure to use our pointer (that we allocated in Delphi) as the source of the data for the numpy array (or matrix). Of course, we would have to tell the user not to modify, or reallocate the contents of that memory, it should be considered read only for them. Is that even possible? or is our only choice to create numpy ndarray array object and copy our already allocated memory into the buffer exposed by the ndarray object?

Delphi is perfect. They have run out of things to do! 😀

Developer Express styles are a whole different beast. They wrote them before Delphi had their own styling engine. AFAIK Dev Ex has no intention of supporting VCL styles. That info was from a few years ago, and things may have changed.

I agree that having two methods to access the list data is helpful. Or maybe just because I got used to it from Delphi. Even Delphi has TList.List forever, so in your example if the developer cared about speed they should be doing for i := 0 to list.Count - 1 do DoSomething(list.list[i]); Mind you, I have rarely found that this makes a difference I could actually time, but sometimes it has.

Well, if you come to Pasadena, you can visit and see it running beautifully 😀 We have a bank of 5 servers. Each one is 24 cores and 200GB of ram. They each run about 75 headless windows machines each in a citrix environment. We have 4000 visual tests that are run multiple times per day and it takes about 1.5 hours to complete a full run on that bank. The key is that we wrote our own GUI automation over the years. All we do is send keystrokes and mouseclicks to the UI. However, there are several caveats that we have developed over the years to make it work. 1. the test case NEVER contains screen coordinates. We have methods like ClickOnMenu(aMenu:TMenu,'File|Open'). That method queries the TMenu and finds coordinates of the 'file' menu item, clicks on it and finds coordinates of the open menu item, then clicks on it. Similar is ClickOnControl(form:TForm;control:TControl). The testing system finds the open form, finds the control. finds the coordindates and then sends a mouse click in the middle of the control. There are other variants if you dont exactly want to click in the middle. So in the test is says ClickOnControl(form1, form1.button1). That way, if the developer changes the form, i.e. moves button1 around, then the test is fine. If they delete button1, the test stops compiling. That being said, we wrote tons of these types of methods that are specific for the controls we use, to accommodate their oddities, like virtual string tree etc. It did not happen overnight. 2. We have a small delay after every input except certain cases. This small delay is generally enough. We also have hooked into the idle processing of the program so after sending a mouseclick / keyboard press it waits for the onIdle so the program is not processing more messages. There are a few more tricks as well. However, the upshot is that we rarely have a problem with timing any longer. For really variable processes, we have our GUI automation thread wait on a TEvent in the program and the program triggers the TEvent when the process is done so that the test knows to continue. But that is rare. Not so similar from an end user, that just sits there waiting for the screen to refresh. So, the upshot is that it was a lot of work, and likely only worth it if you are going to maintain the same program for a long time. But it can be done and today, new developers in our company have no idea the hard work that went into it and they just write scripts in a fairly high level way and the infrastructure does the rest. The test cases find the problem they are designed to test, about 50% of the time. The rest of the failures are because of bugs that are involved in things the test was doing to get to the point where it was trying to test. The other upshot is that we very, very rarely have regressions. The vast, vast majority of bugs that make it to production are in new features that have not (in hindsight) been sufficiently testing.

@Dany Marmur - the crux of the debate is that GUI testing is hard to maintain. If you do it badly, every time you make a slight change to your GUI, tons of test cases start failing for no reason. Also, GUI testing has all sorts of issues to do with knowing when the action is completed. i.e. if you click on a button, then check for a result, how long do you wait to check for the result. Often test code doing the GUI automation is in another thread, and its hard for that thread to know when the application is done what its supposed to do and then test. If you check some state too early, then the test will fail because the app is done. But then you try on your own computer, and the test passes perfectly, because the app was slightly faster on your computer compared to the testing farm. If you do GUI testing well, all these are less of an issue. Some people like the very localized testing of very specific issues that you can get from a very specific test case. With a GUI test, things can fail for all sorts of reasons, and its hard to track down. But that is also the benefit, you get failures in things you did not think of.

You will probably have better luck posting on the Intraweb forums at https://www.atozed.com/forums/

Does anyone have experience designing developer express VCL skins? We need someone to design skins that mimic the modern MAC OS UI. The one that comes with DevEx is ancient. Please feel free to pass this on and if someone has experience contact us at jobs@denovosoftware.com. Thanks.

Is it possible you are running FastMM5 with memory leak tracking on, in debug mode? That will be much slower than the one that ships with Delphi, as it is tracking all memory allocations and de-allocations for memory leak reporting purposes, bad memory overwrites etc.

A few years back, there was a post about potential cache line conflicts with TCriticalSection https://www.delphitools.info/2011/11/30/fixing-tcriticalsection/ The comments indicate it was fixed for TMonitor, but I wonder if anyone knows if it was fixed for TCriticalSection. Looking at the TCriticalSection code in Delphi Seattle, it is very complex, I guess due to cross platform concerns with records, record helpers and then windows API calls all coming into play. I could not find any code there that seems to move things onto a difference cache line, but I definitely could be missing something. Does anyone have any insight into this?