TDaemon Wiki Demo : start event not fired

[Michael Collier]

Hi,
I'm experimenting with linux daemons and could not get start event to fire in demo application.
https://wiki.freepascal.org/Daemons_and_Services
https://github.com/arminlinder/Lazarus-FPC-Wiki-Code-Samples/zipball/master/

I modified the code below and now it works, so looks like the demo needs a small fix to the Format function call (seems it wants 2 parameters string and number )?

See DaemonUnit1.pas

Code: Pascal  [Select][+][-]

1. procedure TDaemon1.DataModuleStart(Sender: TCustomDaemon; var OK: Boolean);
2. begin
3.   LogToFile('STARTED');
4.   {-m.c.
5.   LogToFile(Format('Daemon %s received start signal, PID:%d', [GetProcessID]));
6.   // Create a suspended worker thread - see DaemonWorkerThread unit
7.   FDaemonWorkerThread := TDaemonWorkerThread.Create;
8.   // Parametrize it
9.   FDaemonWorkerThread.FreeOnTerminate := False;
10.   // Start the worker
11.   FDaemonWorkerThread.Start;
12.   }
13.   OK := True;
14. end;  

Log:

Code: Text  [Select][+][-]

1. 12:54:43 Log created
2. 12:54:43 Daemon received stop signal
3. 12:54:43 Daemon stopped
4. 12:55:08 Daemon installing
5. 12:55:08 Daemon installed
6. 12:55:39 STARTED

[TRon]

https://wiki.freepascal.org/Daemons_and_Services

I modified the code below and now it works, so looks like the demo needs a small fix to the Format function call (seems it wants 2 parameters string and number )?

copy-paste error ?

this is what I read/see:

Code: Pascal  [Select][+][-]

1. procedure TDaemon1.DataModuleStart(Sender: TCustomDaemon; var OK: Boolean);
2. begin
3.   LogToFile(Format('Daemon received start signal, PID:%d', [GetProcessID]));
4.   // Create a suspended worker thread - see DaemonWorkerThread unit
5.   FDaemonWorkerThread := TDaemonWorkerThread.Create;
6.   // Parametrize it
7.   FDaemonWorkerThread.FreeOnTerminate := False;
8.   // Start the worker
9.   FDaemonWorkerThread.Start;
10.   OK := True;
11. end;
12.  

Thus the format only has one used format parameter (did you added the %s yourself, perhaps copied from the second example that does use two format parameter strings ?) 

But yes, that call to format as you have shown will fail because it is missing a string for first parameter (you only supplied one integer with the call to GetProcessID() )

[Michael Collier]

Ahh I think I know what the problem is , I'm using the code from the zip download that contains the error

https://github.com/arminlinder/Lazarus-FPC-Wiki-Code-Samples/zipball/master/

The code in the wiki is correct, but download demo project is wrong?

[TRon]

The code in the wiki is correct, but download demo project is wrong?

Indeed i was copying the wiki entry. Because I did not trusted it I downloaded the zipfile and indeed there the error is present.

You can easily solve that with for example:

Code: [Select]

LogToFile(Format('Daemon %s received start signal, PID:%d', ['the_name_of_your_daemon', GetProcessID]));
or replace it as per wiki entry.

At least it keeps you/us alert 

[Michael Collier]

I added an issue in github
https://github.com/arminlinder/Lazarus-FPC-Wiki-Code-Samples/issues/2

Hopefully the demo will be fixed, it's working great for me..

[ArminLinder]

Corrected! Thanks very much for your contribution.

Armin.