Threads

[Phil Myers]

I want to do some file processing from a PBDLL 60 program that will take a few minutes to process. But during that time, would like the user to be able to interact with the dialog (minimize it for example). I am guessing that creating a Thread to run the file processing is the answer. If so, can anyone point me to a program example of proper Thread processing?

Thanks.

[Daniel Modler]

While your loop or whatever processes the data, it could regularly process the messages in the message queue ... this would be a more simple solution.

Regards


-------------
Daniel
[email protected]

[Phil Myers]

What should I use to get messages? DIALOG DOEVENTS? Thanks a lot for your help Daniel - I'm new at this windows stuff.

[Semen Matusovski]

Phil --
as I understand, your problem is enough simple - you want to have alone "background" process and in reality you don't need seriously think about synñhronization of different tasks.
I think you can analyze an example from PB/DLL' Help ("THREAD").
Roughly speaking, you describe "file creation" in separate function and replace "CALL" by "THREAD CREATE".

[This message has been edited by Semen Matusovski (edited January 05, 2000).]

[Peter Stephensen]

Here is an example

#COMPILE EXE
#INCLUDE "win32api.inc"
 
GLOBAL Flag AS LONG
GLOBAL hDlg AS LONG
 
DECLARE CALLBACK FUNCTION DlgProc
 
FUNCTION PBMAIN
 
    DIALOG NEW 0, "Thread Example",,,200,100,%DS_CENTER OR %WS_SYSMENU OR %WS_MAXIMIZEBOX TO hDlg
    CONTROL ADD BUTTON, hDlg, 100, "Start Thread", 10,10,50,12
    CONTROL ADD LABEL, hdlg, 101, "", 10, 30, 100, 12
    DIALOG SHOW MODAL hDlg CALL DlgProc
 
END FUNCTION
 
CALLBACK FUNCTION DlgProc
 
    SELECT CASE CBMSG
    CASE %WM_COMMAND
        SELECT CASE LOWRD(CBWPARAM)
        CASE 100
            SELECT CASE Flag
            CASE 0 ' Thread not running : start it
                CONTROL SET TEXT CBHNDL, 100, "Stop Thread"
                Flag = 1
                THREAD CREATE ThreadProc(1) TO r&
            CASE 1 ' Thread running : stop it
                CONTROL SET TEXT CBHNDL, 100, "Start Thread"
                Flag = 0
 
            END SELECT
        END SELECT
    
    END SELECT
 
END FUNCTION
 
FUNCTION ThreadProc(x AS LONG) AS LONG
 
    LOCAL z AS LONG
 
    WHILE Flag
        SLEEP 100
        INCR z
        CONTROL SET TEXT hDlg, 101, FORMAT$(z)
    WEND
 
END FUNCTION

[James Moneypenny]

Phil,

I use the following WinMain function to start a program in which I wish the dialog to respond to messages. The main thread creates the dialog then spawns a thread that becomes my main worker thread. After creating the worker thread I let it fall into a DO-LOOP which performs a Dialog Doevents and then sleeps from 10 milliseconds then checks the value of End_Program. If End_Program is true then exit the DO_LOOP close the dialog.
I use this for utility programs that I use to process files which can take a few minutes or serveral hours The use of two threads lets me keep the dialogs responsive to user input.(As you indicated so that the user can minimize the dialog to execute another utility or whatever else needs to be done.)

FUNCTION WinMain (BYVAL hInstance     AS LONG, _
                  BYVAL hPrevInstance AS LONG, _
                  lpCmdLine           AS ASCIIZ PTR, _
                  BYVAL iCmdShow      AS LONG) AS LONG

   'Create dialog window and return handle to hDlg&

   'Create a new thread calling WinMain2 and pass the dialog handle (I also place the handle in a Global Var)
   'WinMain2 is the function that becomes my main thread for this program
   THREAD CREATE WinMain2(hDlg&) TO hThread&
   THREAD CLOSE hThread& TO Result& ' free the thread handle but leave the thread running

   'Loop till Global var End_Program=%true
   do
      'respond to messages
      DIALOG DOEVENTS      
      sleep 10

      'Exit loop if global var End_Program=%true
      IF End_Program=%true THEN
         EXIT DO
      end if
   loop

   DIALOG END hDlg&, 0


 END FUNCTION  ' WinMain

James

[This message has been edited by James Moneypenny (edited January 06, 2000).]

[Phil Myers]

Thanks everybody for your help, especially for the sample code.

Phil