In the creation of a TThread in Linux, openSuse recently installed, causes an exception and close the application.

Even without the debug same resul t.By what I've read on wiki about it, the error should appear only under debug.

Anyone knows something about it?

2011/11/24 Everton Vieira :

Use:

{$DEFINE UseCThreads}

E.g:

program project1;
{$mode objfpc}{$H+}
{$DEFINE UseCThreads}

uses

  {$IFDEF UNIX}{$IFDEF UseCThreads}
  cthreads,
  {$ENDIF}{$ENDIF}
  Interfaces, ....

I'll use it tomorow, just this and will work?

Thanks
Everton

2011/11/24 silvioprog

2011/11/24 Everton Vieira :

I'll use it tomorow, just this and will work? Thanks Everton

In my projects, it has worked very well. :)

Why should set $define usecthreads? only $ifdef linux doesn?t solve the issue?
________________________________
William de Oliveira Ferreira
Bacharel em Sistemas de Informa??o

2011/11/24 silvioprog

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William Oliveira Ferreira wrote

Why should set $define usecthreads? only $ifdef linux doesn?t solve the issue?

The default projects of Lazarus contain the following code:

uses

   {$ifdef unix}{$ifdef usecthreads}
   cthreads,
   {$endif}{$endif}
   ...

The "cthreads" unit is the one that must be included for threading support on Unix systems. Using a linux system merely satisfies the "ifdef unix" condition, but you need to define "usecthreads" as well or remove the check completely (you should leave the check for Unix though as the "cthreads" unit is not available for e.g. Windows).

Regards,
Sven

Thanks for the awnser, Sven, but, my question is why not only use {$ifdef unix}
cthreads
{$endif}
and i didn?t understand yet...

________________________________
William de Oliveira Ferreira
Bacharel em Sistemas de Informa??o

2011/11/25 Sven Barth

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Using unit "cthreads" also means linking to the C library. As not every applications needs threading (and thus the linking to the C library) this was made optional. If you use Lazarus with a GTK2 or Qt based LCL then you might as well remove the "ifdef usecthreads" as the two mentioned widgetsets include references to the C library, so it doesn't matter whether you use "cthreads" or not. On the other hand if you'd use fpGUI (or fpGUI-LCL) then you might wish to not include "cthreads" as there no linking to the C library is necessary.

I hope it is more clear now.

Regards,
Sven

If you want to use threads in your program, then the above is the correct way.

The cthreads define is only for packages. When your project uses a package, that uses multiple threads, it enables multithreading for the project by defining -dcthreads.

Mattias

Because using cthreads causes the program to be linked against libc, which people may not automatically want.

Henry

Thanks, now became more clear
________________________________
William de Oliveira Ferreira
Bacharel em Sistemas de Informa??o

2011/11/25 Sven Barth

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