The test TestForceKill and undelaying KillThread function does not kill the thread as experienced before under Linux

[bigopensky]

Hi, thank you for your great units. The code is easy to use.

I'm running Ubuntu with FreePascal 3.2.0 and Lazarus 2.0.12 and I use the matter it to check if the KillThread(ThreadID) behavior of the cthreads has common issues.

I have the issue that the KillThread(ThreadID) won't kill anything despite of giving a positive call result of 0, as written in the handbook. The thread continues the Execute part (..see attached script TestAsync.zip).

I have used your test program ezthreads_tester.lpr, extract the relevant part and added some timestamps (...see TestEzAsync.zip), to get a "second opinion" and to see if the KillThread issue is a "feature" under Linux. It seems to me, that there are the same issues in both programs (TestAsync and TestEzAsync). As you see I set the sleep time of the thread to 10 s, the program should be killed after 50 ms but the the program is running through the complete 10 s defined by the sleep time (..see CONFIG TestEzAsync and OUTPUT TestEzAsync).

I got similar results with my clunky command loop test when i call kill the execution process remains and jumps back to the next input prompt (OUTPUT TestAsync).

** Question 1** Is this behavior for cthread Linux specific and KillThread(...) malfunctioned?

** Question 2** Is there a possibility, to solve that issue BEYOND the permanent commented common solution, to flag the Execution procedure to stop at a certain point (in a loop for example)? I'd like to use the timeout-kill feature in a socket connection context (SQL request for example).

CONFIG TestEzAsync

  LThread:=TEZThreadImpl.Create;
  LThread
    .AddArg('sleep',10000)  // < -------------- HERE
    .AddArg('start',Now)
    .Settings
      .UpdateMaxRuntime(50) // <------------ HERE
      .UpdateForceTerminate(True)  //non-graceful termination, but guarantees no dangling threads after timeout
      .Thread
    .Events
      .UpdateOnStopNestedCallback(@CheckElapsed)
      .Thread
    .Setup(@Setup)
    .Start;

OUTPUT TestEzAsync

TestForceKill: force kill start 30-12-99 13:27:07
TestForceKill::CheckElapsed::elapsed time - 51
TestForceKill::force kill finished 30-12-99 13:27:17 <------- 10 s left

OUTPUT TestAsync

------- START --------
PROMPT> kill
KILL.REQUEST: 30-12-99 13:46:18
KILL.RESULT:  0 0 - means OK 30-12-99 13:46:18 <------- should stop here 
PROMPT> exit
----- READY ----------
```

TestAsync.zip TestEzAsyn.zip

[mr-highball]

Hey @bigopensky 👋

Thanks for the kind words on my code. I'll look into your example within a day or two and write back when I've had some time to test.

[mr-highball]

Without looking on my computer or opening an Ubuntu instance this is just a guess, but could you try and add a Yield(); after the sleep; function call on this line (in ezthreads.pas of your local copy of the library)

https://github.com/mr-highball/ezthreads/blob/master/src/ezthreads.pas#L705

And after this sleep

https://github.com/mr-highball/ezthreads/blob/master/src/ezthreads.pas#L718

If I don't hear back from you I'll still be looking into it and will reply but this may be quicker since you already have the tests / OS

[bigopensky]

Hm ... Yield is unknown in that part of these functions.