Hi!

I read the Wiki about this article, it's looks like very complicated for me. :-( Can anybody show me a very simple example?
Below is a code, i would like to run it multithread both under Windows and Linux.

Program Sorting;
const
	n = 999000;
var
	data : array [1..n] of integer;
	i, j, t: LongInt;
begin
		for i := 1 to n do
			data[i]:=random(32768);
		for i := 1 to n-1 do
		begin
			for j:=i+1 to n do
			begin
				if data[i]<data[j] then
				begin
					t:=data[i];
					data[i]:=data[j];
					data[j]:=t;
				end;
			end;
		end;
end.

Best regards, G

On Tue, May 26, 2015 18:12, Géza Kovacs Géza wrote:

Hi!

What exactly shall be processed in parallel ("multithreaded") according to your expectation? FPC doesn't provide any means for automated splitting complex task into multiple smaller tasks spawned in parallel threads if that's what you meant.

Tomas

I read the Wiki about this article, it's looks like very complicated for

me. :-(

Can anybody show me a very simple example?

Well, it surely is not a beginner's topic. Tell me, if I give:

type
  TMyThread = class(TThread)
    procedure Execute; override;
  end;
procedure TMyThread.Execute;
begin
  WriteLn(i);
end;
begin
  with TMyThread.Create(true) do begin
    FreeOnTerminate := true;
    Start;
  end;
end.

does it make sense to you?

Géza Kovacs Géza wrote

I read the Wiki about this article, it's looks like very complicated for me. :-(

AFAIK, there are examples on how to create TThreads in the fpc Wiki.

OTOH performance optimization via threads on multi-Core systems is not the original target of thread programming, but of course it's a decent way t make use of it.

Delphi does provide easy to use library calls for this (using the "Anonymous" syntax). AFAIK, fpc does have the "Anonymous" syntax since some time, and hopefully the library will be enhanced for such "parallel loops" some day soon.

Before this, you need to create the threads using TThread.

In fact doing a thread pool would be more appropriate.

I already did a workable draft of a thread pool unit that is usable for such tasks, but provided that a Delphi compatible "Anonymous parallel loop" library might be the better way to go I stopped working on that.

-Michael

"Michael Schnell" wrote

Delphi does provide easy to use library calls for this (using the

"Anonymous" syntax). AFAIK, fpc does have the "Anonymous" syntax since some time, and hopefully the library will be enhanced for such "parallel loops" some day soon.

Where did you get the idea that we already have that? Someone /is/ working on it (or is even finished), but nothing is in trunk yet.

Regards,
Sven

Sven Barth wrote

Where did you get the idea that we already have that? Someone /is/ working on it (or is even finished), but nothing is in trunk yet.

We discussed this in the fpc-devel List and I learned that Delphi has the "anonymous" syntax since D2009. It was mentioned in several discussions.

So I had the - seemingly wrong - impression that it already is available.

-Michael

Hi!

Can anybody send me a "Pascal Multithreading tutorial for beginners" or similar document (if it exist)?
What is the simplest method to learn and understand it?

Best regards, G

2015-05-30 6:28 GMT+02:00 Géza Kovacs Géza :

Hi! Can anybody send me a "Pascal Multithreading tutorial for beginners" or similar document (if it exist)?

I like this one. Old but ideas are there.

http://thaddy.co.uk/threads/

Antonio

In our previous episode, G?za Kovacs G?za said:

Can anybody send me a "Pascal Multithreading tutorial for beginners"

Search for Martin Harvey (and "Delphi" "threads")