Beefy Boxes and Bandwidth Generously Provided by pair Networks
There's more than one way to do things
 
PerlMonks  

Re^3: weird case of memory corruption? -- Tk ProgressBar bugged?

by Marshall (Canon)
on May 12, 2021 at 11:04 UTC ( #11132465=note: print w/replies, xml ) Need Help??


in reply to Re^2: weird case of memory corruption? -- Tk ProgressBar bugged?
in thread weird case of memory corruption?

I ran this code on v5.24 with good looking GUI, but with run time error:
Use of uninitialized value in numeric ge (>=) at C:\Users\xxxx\Documen +ts\PerlProjects\Monks\node_id=11132441.pl line 31. WARNING: $pid{ex1}{val} NOT FOUND!! ("ex1", { as => "temp", val => undef })
I am a bit perplexed.

Update: I changed:

$repeat->cancel() if $pid{ex1}{val} >= 65; # to the following... $repeat->cancel() if ($pid{ex1}{val} >= 65); and that seems to work better.

Replies are listed 'Best First'.
Re^4: weird case of memory corruption? -- Tk ProgressBar bugged?
by Discipulus (Abbot) on May 12, 2021 at 11:28 UTC
    Hello Marshall,

    this is exatcly the point: my code show the bug that happens only sometimes. Try to execute the code many times:

    >perl tkprogressbar2.pl Use of uninitialized value in numeric ge (>=) at tkprogressbar2.pl lin +e 31. WARNING: $pid{ex1}{val} NOT FOUND!! ("ex1", { as => "temp", val => undef }) >perl tkprogressbar2.pl >perl tkprogressbar2.pl >perl tkprogressbar2.pl >perl tkprogressbar2.pl Use of uninitialized value in numeric ge (>=) at tkprogressbar2.pl lin +e 31. WARNING: $pid{ex1}{val} NOT FOUND!! ("ex1", { as => "temp", val => undef })

    L*

    There are no rules, there are no thumbs..
    Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.
      OK. Your point is accepted and verified by me on Perl v5.24.

      I actually saw this in my testing, but I couldn't believe my own eyes!
      The exact same source code can produce different results when run more than once.

      I am flabbergasted! This is true, but I don't know why or how?

      More Info:
      Updating a Windows GUI is an extremely expensive operation.
      If you have a loop that will do say 10,000 operations, and you want to show progress via a percent or a progress bar, calculate whether or not the progress bar will move before you update the GUI's value - do this at most 100 times (each one percent for a 100% bar) and probably less than that! The difference in performance between calling the GUI 10,000 times vs 100 times is astonishing!

Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?
Node Status?
node history
Node Type: note [id://11132465]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others taking refuge in the Monastery: (4)
As of 2021-08-05 06:50 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    My primary motivation for participating at PerlMonks is: (Choices in context)








    Results (44 votes). Check out past polls.

    Notices?