Does Clarion 8 offer anything for exception handling? I know as of Clarion 5 there was no support for things like try / catch but that was released almost 10 years ago. I can't seem to find any info on how to recover from exceptions in C6 to C8 unless I was using Clarion# (aka Clarion.NET) which I'm not. If there's definitely nothing like try / catch, are there any tricks or hacks that can be used to not have a program crash when an exception is thrown even if it goes unhandled?
If it helps, I'm using version 8.0.0.8778.
EDIT 1:
Here is some sample code for a basic program that should supposedly illustrate the feature PROP:LastChanceHook, however, I can't get it to work. When I run this program, I see the first message "Start", but then nothing happens. I've tried returning 0 or 1 from Hook but that hasn't made a difference either. Every time I run this, I have to go onto the Task Manager and end the process for the program because it's not being killed.
PROGRAM
INCLUDE('CWEXCPT.INT'), ONCE
MAP
Hook(*ICWExceptionInfo), LONG
Test(LONG,LONG)
END
CODE
MESSAGE('[Sample] Start')
SYSTEM{PROP:LastChanceHook} = ADDRESS(Hook)
Test(10, 0) ! Intentionally causes an exception
MESSAGE('[Sample] After Test')
RETURN ! Tried removing this, no difference
Hook PROCEDURE(*ICWExceptionInfo info)
CODE
MESSAGE('[Sample] Start Hook')
IF info &= NULL THEN RETURN 0 END
Message('An exception!')
RETURN 1 ! 0 = don't kill, anything > 0 = tell RTL to kill the thread
Test PROCEDURE (LONG a, LONG b)
CODE
a %= b
Yes, take a look at prop:LastChanceHook in the help. It may provide enough function for your needs.
In other cases, the info at this link might also be useful:
http://clarionsharp.com/blog/tracking-down-those-pesky-gpfs/
In the next public build of C8 (it's presently Sept 27, 2012), the buttons on that exception display (shown at the link above) can be customized a bit.
Related
I have a script I'm trying to write to process a large amount of data. There are, of course, potential for errors. In the script I need to connect to databases. If the script encounters an error, the code never reaches the point where the connection to the database is terminated. I'd like to have something in my python code that will recognize an error occurs, not matter where, and if nothing else at least close those databases. Does something like this exist? I know I can use try/except, but that would only work if I know exactly where I could get the error? I'm basically looking for a catchall to close my databases in the event an error occurs in a location I didn't anticipate.
To run certain cleanup code even if there is an error, use the finally block:
try:
# do stuff, possible exception
except:
# run this if exception
finally:
# always run this, even if exception
Reference: https://docs.python.org/3/tutorial/errors.html#defining-clean-up-actions
checkmodel([Some Model]) opens the GUI "Dymola Messages", tab "Translation" and displays Errors, Warnings, and Messages.
Does anyone know how to write these infos to a logfile or get them as kind of return value of checkModel(). All I've found in the documentation was, that checkModel() only returns a success-boolean. Are these infos saved temporarily somewhere?
Note, that I only want to apply checkModel() but not actually translating the code.
I finally found a solution at least for Dymola 2016 and newer, so if someone is interested - here it is (it is not very user-friendly, but it works):
The key-command is getLastError() which not only returns the last error (as one could think...), but all errors that are detected by checkModel() as well as the overall statistics.
All informations are sampled in one string, in which the last lines looks like:
"[...]
Local classes checked, checking <[Some Path]>
ERROR: 2 errors were found
WARNING: 13 warnings were issued
= false
"
Following operations will return the number of actual errors (for warnings it is more or less the same):
b = checkmodel([Some Model])
s = getLastError()
ind1 = Modelica.Utilities.Strings.findLast(s,"ERROR:")
ind2 = Modelica.Utilities.Strings.findLast(s," errors were found")
nErrors = Modelica.Utilities.Strings.substring(s,ind1+6,ind2) //6 = len(ERROR:)
nErrors = Modelica.Utilities.Strings.replace(nErrors," ","")
nErrors
= "2"
Note:
I used findLast as I know, that the lines of interest are at the very end of the string. So this is significantly faster than using find
This only works, if the line "ERROR: ...." actually exists. Otherwise, the substring call will throw an error.
Of course this could be done in less lines, but maybe this version is easier to read.
NOTE: This will only works with Dymola 2016 and newer. The return-string of getLastError is of a different structure in Dymola 2015 and older.
The following should handle it:
clearlog(); // To start fresh
Advanced.TranslationInCommandLog=true;
checkModel(...);
savelog(...);
This is mentioned in the Dymola User Manual Volume 1, section "Parameter studies by running Dymola a number of time in “batch mode”" on pg 630 or so.
In Visual Basic I create an Application Object and start it:
gApp = New CANoe.Application
gMeasurement = gApp.Measurement
gApp.Open(arrArgs(0), False, False)
gMeasurement.Start()
Once the application finishes processing the data two possible scenarios may happen: (i) the data file was corrupt and (in normal circumstances) an allert window is raised and (ii) the data file was ok. In (ii) case I can quite the Application with gApp.Quit(). However in case (i) gApp.Quit() does not work, since the program expects input from the user (although often I do not see the window at all).
Question 1: how can I quite the process corresponding to gApp? Currently I am quiting this in this way:
For Each p As Process In Process.GetProcesses
If p.ProcessName = "CANoe32" Then
p.Kill()
End If
Next
In general this is a bad solution since more instances of CANoe32 may run (although in this particular case only one process of this binary may run on the system).
Question 2 what would be a more elegant solution to quit the gApp in case it has child windows?
Any comments are very helpful
A possible solution to the problem would to use something similar to this ticket:
how-do-i-get-the-process-id-from-a-created-excel-application-object
ok here is my code :
For i = 0 To 10
Dim tTemp As Threading.Thread = New Threading.Thread(AddressOf dwnld)
tTemp.IsBackground = True
'tTemp.Start(geturl)
lThreads.Add(tTemp)
'MsgBox(lThreads.Item(i).ThreadState)
Next
I create a list of threads with 10 threads, assign them a function, properties and add them to the list.
'While ListBox2.Items.Count > 0
For i = 0 To lThreads.Count - 1
If (lThreads.Item(i).ThreadState = 12) Then
If (ListBox2.Items.Count > 0) Then
lThreads.Item(i).Start(geturl)
If (i = lThreads.Count - 1) Then
i = 0
End If
Else
Exit For
End If
'MsgBox(lThreads.Item(i).ThreadState)
ElseIf (lThreads.Item(i).ThreadState = 16) Then
lThreads.RemoveAt(i)
Dim tTemp As Threading.Thread = New Threading.Thread(AddressOf dwnld)
tTemp.IsBackground = True
lThreads.Add(tTemp)
If (i = lThreads.Count - 1) Then
i = 0
End If
End If
Next
What's happening is, i see the threads stop after the function dwnld is completed. So i first check for the state (12 means background and unstarted). On case 12 start the thread and in case 16 (stopped) remove that particular thread and add a different thread like i add 10 above.
Also there is a check when the i counter reaches last number, restart the whole loop by assigning i=0.
The program downloads some web pages, the url is passed from the listbox2. The geturl will pass the url and remove it from the list. So when the listbox is empty, exit the for loop.
But the above code is running for only 11 times and it does not restart. I tried using a lable and goto but it simple hangs.
Can anyone tell me what to do?
What i want is to maintain 10 threads to keep downloading the web pages and when the list is empty, exit the function.
Trying to manually manage your own custom pool of threads is probably the wrong approach here. Use ThreadPool.QueueUserWorkItem or preferrably the new Task class. The thread pooling is managed for you which greatly simplifies the code. Completely scrap this code and start over using one of the techniques I just mentioned. If you run into problems implementing either of these techniques then post a more specific question.
Micro-management of threads is, well, just a really bad idea. The moment I see anyone trying to maintain a list of threads that are continually created, terminated and destroyed I just know they are doomed. I have seen experienced professionals trying to do it - it's fun looking on, waiting for the inevitable spectacular failure after months of trying to fix the unfixable.
Thread pools are, typically, nothing of the sort. They are usually a pool of tasks - task class instances on a producer-consumer queue - that several threads feed off as and when they are free to do work. The work threads auto-manage themselves by getting new tasks themselves when they have finished with the old one - no need for any higher-level micro management.
Listen to #Brian - forget managing lists of threads, checking their state and all that gunge. It'll just make you ill. Go with ThreadPool.QUWI or Tasks.
I'm currently trying to code an add-on the popular game World Of Warcraft for a friend. I don't understand too much about the game myself and debugging it within the game is difficult as he's having to do all the testing.
I'm pretty new to Lua, so this may be a very easy question to answer. But when a Lua error occurs in WoW it throws it on screen and gets in the way, this is very bad to a game player as it will stop their gameplay if it throws the exception at the wrong time. I'm looking for a way to cleanly handle the error being thrown. Here's my code so far for the function.
function GuildShoppingList:gslSlashProc()
-- Actions to be taken when command /gsl is procced.
BankTab = GetCurrentGuildBankTab()
BankInfo = GetGuildBankText(BankTab)
local Tabname, Tabicon, TabisViewable, TabcanDeposit, TabnumWithdrawals, remainingWithdrawals = GetGuildBankTabInfo(BankTab)
p1 = BankInfo:match('%-%- GSL %-%-%s+(.*)%s+%-%- ENDGSL %-%-')
if p1 == nil then
self:Print("GSL could not retrieve information, please open the guild bank and select the info tab allow data collection to be made")
else
self:Print("Returning info for: "..Tabname)
for id,qty in p1:gmatch('(%d+):(%d+)') do
--do something with those keys:
local sName, sLink, iRarity, iLevel, iMinLevel, sType, sSubType, iStackCount = GetItemInfo(id);
local iSum = qty/iStackCount
self:Print("We need "..sLink.." x"..qty.."("..iSum.." stacks of "..iStackCount..")")
end
end
end
The problem being when checking to see if p1 is nil, it still throws a Lua error about trying to call p1 as nil. It will be nil at times and this needs to be handled correctly.
What would be the correct most efficient way to go about this?
You might want to wrap your function in a pcall or xpcall which enables you to intercept any error thrown by Lua.
Aside of that, I personally find this construct easier to read:
p1=string.match(str,pat)
if p1 then
-- p1 is valid, eg not nil or false
else
-- handle the problems
end