Problem with VAR

RogerInHawaii

I'm having some very strange symptoms.

I have some variables defined like:

   VAR
         byte  _A, _B, _C

Inside one of my methods I am setting that first variable, _A

PUB MyMethod
    
   _A := 9

If I print out the value of _A (using the FullDuplexSerialPlus to the Serial Terminal) while I'm still inside MyMethod it shows that the value of _A is indeed equal to 9.

But if I print out the value of _A after I exit MyMethod it comes out as 0. In fact, I have another method that just prints out the value of _A. If I call that method FROM WITHIN MyMethod, it also shows that _A is zero. So, if I print out the value of _A directly within MyMethod (with direct calls to the FullDuplexSerial methods) it comes out correctly, but if I call my PrintOutA from within MyMethod, _A comes out as being 0. ?!?!?

This behavior also seems to be rather inconsistent, in that I can successfully set other global variables and have them maintain their values, but SOME of them don't.

Any suggestions?

jazzed

Maybe you can create a very short reproduce-by code snippet to share ? It would be very useful to see that.

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--Steve


Propalyzer: Propeller PC Logic Analyzer
http://forums.parallax.com/showthread.php?p=788230

RogerInHawaii

Yes, it would be nice to be able to do that. But this is one huge program and I'm only encountering it in one particular place in the program. So I really doubt that I can come up with a small snippet that would reproduce it. It's got me baffled.

jazzed

Maybe it's time to try Hanno's ViewPort debugger?

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--Steve


Propalyzer: Propeller PC Logic Analyzer
http://forums.parallax.com/showthread.php?p=788230

Philldapill

Roger, are you sure that these two places where you "call" _A are in the same cog? Those variables are cog specific, and if you are running two different instances of that code, that could be your problem.

RogerInHawaii

They're in the same cog. But I finally realized the problem. And it was due to a typo! Aaaarrrggghh!

I think I'm going to come out with a line of T-shirts that says "Typos Happen".

CassLan

That sounds like a great shirt

Rick

mpark

I think the shirt should have a typo.

Phil Pilgrim (PhiPi)

It has two already.

-Phil

QuattroRS4

Nice catch Phil!

Regards,
John

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'Necessity is the mother of invention'

Those who can, do.Those who can’t, teach.

StefanL38

Hello,

I want to correct a detail.

VAR-variables are NOT cog-specific they are object-specific.

This is a big difference ! As long as methods are called from the SAME object(= same *.SPIN-file)
all VAR-variables defined in that *.SPIN-file are accessible even ACROSS cogs !

here is a small democode that shows that

CON
  _clkmode = xtal1 + pll16x
  _xinfreq = 5_000_000

  
VAR
  long heart_stack[noparse][[/noparse] 20]
  long CogStack1[noparse][[/noparse] 20]
  long CogStack2[noparse][[/noparse] 20]
  
  long MyTestVar

OBJ
  debug : "FullDuplexSerial"


PUB Main
'the FIRST PUB-Method inside a spinfile is ALWAYS the startpoint where the program starts to run
  debug.start(31, 30, 0, 9600)
  
  MyTestVar := 100
  debug.str(string("Start MyTestVar="))
  debug.dec(MyTestVar)
  debug.Tx(13)

  cognew(M1,@CogStack1)
  cognew(M2,@CogStack2)
  
  repeat
    waitcnt(clkfreq + cnt)
    debug.str(string("MyTestVar="))
    debug.dec(MyTestVar)
    debug.Tx(13)



PUB M1
  repeat
    waitcnt(ClkFreq * 3 + cnt)
    MyTestVar := 1


PUB M2
  repeat
    waitcnt(ClkFreq * 5 + cnt)
    MyTestVar := 2

best regards

Stefan

mpark

Phil Pilgrim (PhiPi) said...
It has two already.

-Phil

Huh? I don't get it.

Phil Pilgrim (PhiPi)

"Happen" is capitalized, and there's no period at the end of the sentence. (Yeah, I know. It's horribly pedantic, isn't it? Moreover, the claim could be made that it's a title or headline.)

This same shirt could be adapted for blood bank workers as well: Type Os happen.

-Phil