While researching some other historic information about Delphi, I bumped into this thread: New DPMI host – delphi.
If is a small thread describing what kinds and versions of DPMI hosts were available to run Turbo Pascal based programs.
DPMI stands DOS Protected Mode Interface: a way for real mode DOS programs to access protected mode features (mainly memory above the 1 megabyte barrier).
I had plainly forgotten that the DPMI host shipped with Delphi 1, and wasn’t aware you could have a 32-bit DPMI host at all.
Just found this great answer by vcldeveloper to autoscroll a readonly logging memo in Delphi which works from Delphi 1 and up (:
For such a simple task, you don’t need to buy a commercial component! All you need to do is to send an EM_LINESCROLL message to that memo control, to make it scroll to the last line:
procedure ScrollToLastLine(Memo: TMemo);
begin
SendMessage(Memo.Handle, EM_LINESCROLL, 0,Memo.Lines.Count);
end;
If your memo is read-only to users and is updated automatically by the application, you can put a call to the above procedure in its OnChange event-handler, so that whenever the text inside the memo is changed, it is automatically scrolled down to the last line.
The with clause effectively opens the scope containing field identifiers of the specified record variable, so that the field identifiers may occur as variable identifiers. (Thereby providing an opportunity for the compiler to optimize the qualified statement.)
Screenshots of this 1975 book are below the fold.
The Delphi (actually even before that Turbo Pascal compiler) has no measurable difference between with and non-with code.
The debugger however, still does not support with, and there are other drawbacks of which one is below.
The below code example is just one of many. I show it because I recently bumped into doing some long overdue code porting to Delphi XE3.
Since I’ve been bitten by using with a couple of times before, it didn’t take me long to find the cause.
Example code where FIConData is of type NOTIFYICONDATAW that used to compile fine:
with FIconData do
begin
cbSize := SizeOf(FIconData);
Wnd := Self.Handle;
uID := $DEDB;
uFlags := NIF_MESSAGE or NIF_ICON or NIF_TIP;
hIcon := Application.Icon.Handle;
uCallbackMessage := WM_CAS400NTIcon;
StrCopy(szTip, PChar(Caption));
end;
A cool page for historic perspective is R3R: Pascal Features in Popular Compilers, hopefully someone will update it to more modern versions of the mentioned compilers.
Few people know about a Delphi language feature that has been present since Delphi 1: prepending the type definition with a type keyword to make the type getting a new identity.
Each time I use it, I have to do some browsing for the consequences, and this time I wrote down some notes and created a small example program (source is also below).
WebSphere MQ has Queues where you can put and get messages. It also has Queue Managers to which you connect, and that provide queuing services and manages queues.
Both Queues and Queue Managers have names that can be up to 48 (single byte) characters long.
Those names mean totally different things, so though the have similar data types, they have a different identity.
Few people know the name Peter Sollich, as he always chose not to be a public figure (for instance, he is absent on the Outstanding Technical Achievement video).
Peter has been very important for both the Delphi and the .NET worlds: he was the original author of the 32-bit product that became the Delphi x86 compiler.
A few interesting links came up when using his name in some Google searches.
I just watched this interview with Anders Hejlsberg for the first time. This is truly an amazing interview. It’s rather long, about 1 hour, but it is so worth it. I’m not giving anything away… you’ll have to just watch and enjoy.
I am giving a few things away: trip down memory lane, putting big parts of software development history into perspective,
Since Anders has been so versatile, influential and still humble, this is a must watch for anyone in the software field. To quote Research Channel:
This episode features industry luminary, Anders Hejlsberg. Before coming to Microsoft in 1996 he was well noted for his work as the principal engineer of Turbo Pascal and the chief architect of the Delphi product line. At Microsoft, he was the architect for the Visual J++ development system and the Windows Foundation Classes (WFC). Promoted to Distinguished Engineer in 2000, Anders is the chief designer of the C# programming language and a key participant in the development of Microsoft’s .NET Framework. In this show, Anders is joined by a surprise guest. This episode of ‘Behind the Code’ is hosted by Barbara Fox – former senior security architect of cryptography and digital rights management for Microsoft.
(PS: how a video published in the C# 3 era can be so current <g>).
And if you feel for more, here, here, here, here and here are some more, are a few lists of videos where Anders speaks.
From a historic perspective, I like these most:
The Wiert Corner - irregular stream of stuff 