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Problem creating External Event Handler [message #1829767]

Fri, 10 July 2020 06:56

Eclipse User

Hello,

I am trying to implement an External Event Handler for some FBs I use for communication.
For this I looked at the FDselectHandler and tried to use most of the Code from there with a couple changes.
I changed the addComCallback function to use CEvenSourceFB instead of CComCallback and made the same changes in the run() method.
Of Course i also changed the Name from CFDSelectHandler to my own class.

When compiling I get a linker error telling me "undefined reference to mHandlerIdentifier". I still use the DECLARE_HANDLER and DEFINE_HANDLER macros and didnt Change anything there.

is there another step to doto Register the handler?

thanks in advance

Re: Problem creating External Event Handler [message #1829768 is a reply to message #1829767]

Fri, 10 July 2020 07:05

Eclipse User

HI,

you need to add

forte_add_handler(CLASS_NAME FILE_NAME_OF_THE_CLASS_WITHOUT_EXTENSION)

in the CMakeLists.txt file.

Example:

forte_add_handler(CFDSelectHandler sockhand)

Re: Problem creating External Event Handler [message #1829769 is a reply to message #1829768]

Fri, 10 July 2020 07:14

Eclipse User

thanks a lot.
everythings working now.

Re: Problem creating External Event Handler [message #1829792 is a reply to message #1829769]

Fri, 10 July 2020 11:12

Eclipse User

May I ask what changes you need in the FDSelecthandler? Is it something that we should also do in the public version?

If it is just because of the CComCallback I want to point out that C++ allows multiple inheritence and you can inherit your FB from CEvenSourceFB and CComCallback. To be more specific the CComCallback was introduced for such use cases.

Cheers,
Alois

Re: Problem creating External Event Handler [message #1830186 is a reply to message #1829792]

Mon, 20 July 2020 04:35

Eclipse User

Hello
Sorry for the late answer.
Yes it was to make it use CEventSourceFB instead of CComCallback. So probably not for the public Version.

Thanks for the tip. I will add the inheritance from CComCallback to the FB and use the FDSelectHandler.

Best regards,
Niklas Huhs

Re: Problem creating External Event Handler [message #1830210 is a reply to message #1830186]

Mon, 20 July 2020 15:01

Eclipse User

I hope this makes your live easier. If not please let us know so that we can fix issues that you may discover.

Re: Problem creating External Event Handler [message #1830314 is a reply to message #1830210]

Thu, 23 July 2020 04:49

Eclipse User

Hello again

I have encountered one issue when using the fdselect handler for my own FBs.
in the line:
startNewEventChain(callee->getCommFB());

the function "virtual CBaseCommFB *getCommFB()" gets called.

I tried using a reinterpret_cast<CBaseCommFB*>(this) in my own FB but then I get an Error in forte saying: [CDeviceExecution] Couldn't start new event chain because the event has no CEventChainExecutionThread

Is it necessary to add CBaseCommFB to the inheritance?(causes more errors when compiling the FB)

Best regards
Niklas Huhs

Re: Problem creating External Event Handler [message #1830349 is a reply to message #1830314]

Thu, 23 July 2020 15:25

Eclipse User

Hi,

mhmh. in addition inheriting from CBaseCommFB is not a good idea. Can you try changing the virtual CBaseCommFB *getCommFB() to CEventSourceFB*...

Which should fix the compilation problem. But the real problem behind the error message is that you havent set the CEventChainExectuioThread in your event souce FB. The simplest way to do this is to take the CEventchainExectionTrhead from the resource your FB is located in. you can have a look in CBaseCommFB for this.

BR,
Alois

Re: Problem creating External Event Handler [message #1830383 is a reply to message #1830349]

Fri, 24 July 2020 09:32

Eclipse User

Hi,

thanks for your help.
I made the changes and everything is compiling.
I will be able to test it again on my device at the start of next week and will let you know if everything is working.

Best regards,
Niklas

Re: Problem creating External Event Handler [message #1830395 is a reply to message #1830383]

Fri, 24 July 2020 12:27

Eclipse User

Great to hear that. I'll keep my fingers crossed and looking forward to hear from you.

Re: Problem creating External Event Handler [message #1830463 is a reply to message #1830395]

Mon, 27 July 2020 04:39

Eclipse User

Good morning,

so after a bit of work and google, I'm not sure anymore it's possible to just use the FDselectHandler.
-Using CEventSourceFB* getCommFB(){... in the code of my FB doesn't work. (Function won't override because of the missing "const")
-Using CEventSourceFB* getCommFB() const{... returns "invalid convariant type" error.
-same when using FORTE_MyFB* getCommFB() const{...
-using:

forte::com_infra::CBaseCommFB* getCommFB() const{
        return const_cast<forte::com_infra::CBaseCommFB*>(reinterpret_cast<const forte::com_infra::CBaseCommFB*>(this));
    }

comiles and overrides the getCommFB() function but returns the "[CDeviceExecution] Couldn't start new event chain because the event has no CEventChainExecutionThread" even though I added

setEventChainExecutor(pa_poSrcRes->getResourceEventExecution());

in the constructor. (I'm a bit confused here because this worked with my own External Event Handler).

maybe I just don't see the obvious solution right now but I might go back to using a custom handler with CComcallback but without the "getCommFB" function

Best regards,
Niklas Huhs

Re: Problem creating External Event Handler [message #1830482 is a reply to message #1830463]

Mon, 27 July 2020 13:09

Eclipse User

hmh did you alse change the getCommFB in the commcallback class?

Re: Problem creating External Event Handler [message #1830485 is a reply to message #1830482]

Mon, 27 July 2020 13:55

Eclipse User

Well, I wanted to avoid changing existing forte Code and wasn't sure if that was what you meant in the earlier post but I guess that will work.
Thanks again for taking the time to help.

Re: Problem creating External Event Handler [message #1830494 is a reply to message #1830485]

Mon, 27 July 2020 15:34

Eclipse User

Ah sorry for not being to clear about it. Yes I expected that changes to the comcallback would be needed. But I would find such a change something worthwhile to consider for the next 4diac FORTE version.

BR,
Alois

Re: Problem creating External Event Handler [message #1830502 is a reply to message #1830494]

Mon, 27 July 2020 18:13

Eclipse User

No worries. This will definitely save some time for me. I don't expect it to cause any issues but if it does, i will let you know.

Best regards
Niklas Huhs

[Updated on: Mon, 27 July 2020 18:26] by Moderator

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