Lvars.lst and Hvars.lst

[Scotfleiger]

Prior to FSUIPC7 Lvars were saved in file lvars.lst which is used by LINDA for monitoring and setting their values. Would it be possible to copy the list of current Lvars and Hvars to lvars.lst and hvars.lst respectively? The files should be populated when the aircraft is loaded based on the WASM.ini LvarScanDelay variable.

[John Dowson]

  On 1/4/2022 at 11:28 PM, Scotfleiger said:

Prior to FSUIPC7 Lvars were saved in file lvars.lst

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Really? Where is this file created, and how? This is news to me, so can you let me know how you generate that file (or if its automatic) and where it is located. O have never heard of such a file.

  On 1/4/2022 at 11:28 PM, Scotfleiger said:

Would it be possible to copy the list of current Lvars and Hvars to lvars.lst and hvars.lst respectively?

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If you are doing this from code (C/C++), can you just not use the WAPI interface, the following functions:
            void getLvarList(unordered_map<int, string >& returnMap); // Returns a list of lvar names keyed on the lvar id
        void getHvarList(unordered_map<int, string >& returnMap); // Returns a list of hvar names keyed on the lvar id

		void getLvarList(unordered_map<int, string >& returnMap); // Returns a list of lvar names keyed on the lvar id
		void getHvarList(unordered_map<int, string >& returnMap); // Returns a list of hvar names keyed on the hvar id

Alternatively, Hvars are loaded from a .hvar file anyway, so for hvars can you not just use the same file?
For lvars, I guess I could add a lua function to list them to a file (also for hvars I guess) if really needed.

John
 

[Scotfleiger]

Hi John

Thanks for your help again. The lvars.lst is generated by LINDA using calls to ipc.getLvarName(id). It is likely that this ipc call was not implemented when I first modified LINDA with an early version FSUIPC7 as I had to comment out the calls and, hence, no list was created. I have now have a list.

LINDA uses Delphi/Pascal and not C/C++ so calling WAPI is not an option. Without an ipc call I will look at accessing the .hvar lists directly.

[John Dowson]

Hi Andrew.

  On 1/5/2022 at 2:46 PM, Scotfleiger said:

Without an ipc call I will look at accessing the .hvar lists directly.

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I will add an ipc.getHvarName(id) function. This should have been added when I added the ipc.activateHvar(“name”) function but seems to have been missed.
I can post a version here for you to test if you like - may take me a day or two.

John

 

[Scotfleiger]

  On 1/5/2022 at 3:20 PM, John Dowson said:

I will add an ipc.getHvarName(id) function.

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Thank you so much. There is also the paired ipc.getHvarId("name") that would replicate those for Lvars.

[John Dowson]

  On 1/5/2022 at 3:34 PM, Scotfleiger said:

There is also the paired ipc.getHvarId("name") that would replicate those Lvars.

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Sure, I will add that as well.

John

[John Dowson]

Hi Andrew,

please try the attached version, v7.2.15a: FSUIPC7.exe

[Scotfleiger]

V7.2.15a tested.

ipc.getHvarName(n) returns the expected Hvar name and allows me to extract a full list of Hvars. I can also read and write to these Lvars as before.

ipc.getHvarId("name") returns a very large number. For example, for the FlyByWire A32nx:

n = ipc.getHvarId("H:A320_Neo_PFD_BTN_LS_1")
_log ('Hvar = ' .. tostring(n))

returns
Hvar = 1.844674407371e+19

 

[John Dowson]

  On 1/5/2022 at 5:13 PM, Scotfleiger said:

pc.getHvarId("name") returns a very large number. For example, for the FlyByWire A32nx:

n = ipc.getHvarId("H:A320_Neo_PFD_BTN_LS_1")
_log ('Hvar = ' .. tostring(n))

returns
Hvar = 1.844674407371e+19

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Hmm, strange. I presume that hvar exists....I will take a look - tomorrow now.

[Scotfleiger]

It is the same and valid as I fed the results of one into the other.

function test()
    m= ipc.getHvarName(5)
    _log ('Hvar = ' .. m)

    n = ipc.getHvarId(m)
    _log ('Hvar = ' .. tostring(n))

end

returned

:  [EVNT] Execute Command = "test"
:  Hvar = H:A320_Neo_PFD_BTN_LS_1
:  Hvar = 1.844674407371e+19

Good night.

[John Dowson]

Not sure why you are getting that value, but I found an issue which is corrected in the attached version (still not tested though!)FSUIPC7.exe: 

[Scotfleiger]

Hi John, the latest build (version no unchanged) works for both ipc.getHvarName() and ipc.getHvarId(). The correct values are returned. When first run I got a nil error and had to click on Add-ons/WASM/List Hvars to 'load' the Hvars for use.

I am still confused on the difference in use of the Hvars to the traditional Lvars. ipc.activateHvar is said to 'write' to Hvar but takes no parameter. How does this differ from ipc.writeLvar("name", n)? Is there any case for adding ipc.readHvar("name"), ipc.readHvarSTR("name","value"), ipc.writeHvar("name", n) and ipc.writeHvarSTR("name","value")?

Thanks again.

[John Dowson]

  On 1/5/2022 at 9:29 PM, Scotfleiger said:

I am still confused on the difference in use of the Hvars to the traditional Lvars. ipc.activateHvar is said to 'write' to Hvar but takes no parameter. How does this differ from ipc.writeLvar("name", n)? Is there any case for adding ipc.readHvar("name"), ipc.readHvarSTR("name","value"), ipc.writeHvar("name", n) and ipc.writeHvarSTR("name","value")?

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As far as I am aware, hvars have no associated value and are basically JS / HTML events, and should probably be called H:Events (I have seen this term also used).
The FSUIPC WASM just uses the H:varName to execute the calculator code:
      (>H:varName)

I have seen examples where an actual value has been set. However, I don't thing this is an associated value to the hvar, but more like a parameter to an event. There is no way that I know of to actually read the value of a hvar.
If needed, I could allow a parameter to set on a hvar, but up to now I have not seen a need and no one has requested such a feature. This can currently be achieved by using the ipc.execCalcCode(“code”) function, if needed.

  On 1/5/2022 at 9:29 PM, Scotfleiger said:

When first run I got a nil error and had to click on Add-ons/WASM/List Hvars to 'load' the Hvars for use.

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Thats strange - I can only assume that you made the call too soon. Hvars won't be available until a number of seconds AFTER the aircraft has loaded, defined by the LvarScanDelay parameter, which has a default value of 5. However, I recommend increasing this to around 45 if using complex aircraft, such as the FBW A320.
If you check your FSUIPC7.log, you should see when the lvars/hvars are available and if you made the request too soon. I can think of no other cause of such behaviour.

  On 1/5/2022 at 9:29 PM, Scotfleiger said:

Thanks again.

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No problem.

[Scotfleiger]

Thank you John. I am now much  better informed. I was quick off the mark trying to access the Lvars after start up.

[John Dowson]

👍