win32 - How to interrupt execution

[NdotA]

Hi,
this seems to be a common task - but I have no idea how to set about, nor could I find any helpful information in the windows manuals.

When my code enters in a lengthy evaluation of data, I want to be able to abort the execution of this loop. I have a dialog with a progress bar and a cancel-Button. But I cannot click this button while the process is running - so I cannot interrupt or abort the process. Here is my code (I am using fortran, if there is a forum on this site better suited for my problem, please let me know):

            hProgress = CreateDialog(NULL, IDD_PROGRESS, hWnd,  loc(DN_PrgrsDlgProc)) 
            cRslt = 'Schneller Vorlauf 'C
            iRslt = SetDlgItemText (hProgress, IDC_PROGRESSTEXT, cRslt)
            iRslt = UpdateWindow (hProgress)
            hBar = GetDlgItem (hProgress, IDC_PROGRESSBAR)
            iNSteps = (iRunEnd - iiSimZeit) / iiTimeStep
            iCount = 0   
            hAbort= GetDlgItem(hProgress, IDCANCEL)       
            do 
                iiSimZeit = iiSimZeit + iiTimeStep
                if (iiSimZeit .gt. 0) iRslt = DN_Update()       ! t = 0 wird von InitSim gef?llt, daher 0 ?berspringen!
                if (iiSImZeit .gt. iRunEnd) exit
                iRslt = DN_SetLoad ()                           ! EEG-Erzeugungen bestimmen
                iRslt = DN_EuroDispo ()                         ! Strom-Verteilung in Europa                  
                iRslt = DN_AutoDispatch()                       ! Residuallast ausgleichen
                irslt = DN_Eval()                               ! Netzstr?me errechnen
                !iRslt = DN_Redispatch()                        ! Knotenlasten, d.h. Kraftwerke und Kreise an die Netzkapazit?ten anpassen  
                iRslt = DN_SumUp ()                             ! Daten zusammenstellen
                nRun = nRun + 1
                iRslt = DN_OutComes(nRun)                       ! Ergebnisse ausgeben
                iCount = iCount + 1
                iRslt = iCount * 100 / iNSteps
                iRslt = SendMessage (hBar, PBM_SETPOS, iRslt, 0)
            enddo
            lRslt = DestroyWindow (hProgress)

The loop runs for several minutes and I want to be able to stop it without stopping the application. I my mind this boils down to the question how I can make the cancel-button to react to mouse input. Once this is possible I may be able to check the state or process messages in my process-dialog-procedure.

[VictorN]

The usual way to work with a lengthy calculations etc. with the possibility to cancel it is putting these lengthy calculations in a worker thread.
Unfortunately I don't know if it's possible in FORTRAN (since I don't use it for about 30 years.)

[2kaud]

For an article on using worker threads with c, see:
http://www.flounder.com/workerthreads.htm

[NdotA]

Oh, I almost feared that this might not be as easy as it looks.
Thanks to you both, I will try my luck with threading

N.

[2kaud]

The 'cheat quick and dirty' way is to use PeekMessage() in the calculation loop and exit the calculation if required messages are in the message queue. This will slow down the calculation loop (probably substantially). But much better to do it 'properly' using a worker thread.

https://learn.microsoft.com/en-us/wi...r-peekmessagea

[NdotA]

The 'cheat quick and dirty' way is to use PeekMessage() in the calculation loop and exit the calculation if required messages are in the message queue. This will slow down the calculation loop (probably substantially). But much better to do it 'properly' using a worker thread.

https://learn.microsoft.com/en-us/wi...r-peekmessagea

That is an idea. I could set a counter to send this message once for say every 500 cycles, say for a time of about one second. This would be a reasonable reponse time without too much burden in performance.

Thanks

N.A

[ana025jones]

Hi there!

I understand the challenge you're facing with handling long-running tasks in Fortran. One effective approach to allow for user interaction, such as clicking the cancel button, is to implement a separate thread for your lengthy evaluations. By doing so, you can keep your GUI responsive while the processing occurs.

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