Using multiple timers

[Tim Lakinir]

Hi All,
I need to use at least 3 timers to do a variety of different stuff in a program, I'm wondering if this below method is okay, am I doing correctly ?

' Multiple Timers.bas

#COMPILE EXE
#DIM ALL

    #INCLUDE "Win32Api.inc"

 %IDC_ATimer = 101
 %IDC_BTimer = 102
 %IDC_CTimer = 103
 %IDC_GDisplay  = 105

' handles for timers
 GLOBAL hAtim  , hBtim , hCtim AS DWORD



FUNCTION PBMAIN () AS LONG

  LOCAL hSpin AS DWORD
   DIALOG NEW PIXELS, 0 , "My Dialog", 100 ,50 , 300, 300,_
            %WS_SYSMENU, %WS_EX_TRANSPARENT TO hSpin

    CONTROL ADD GRAPHIC, hSpin, %IDC_GDisplay, "", _
             10, 10, 150, 150



     DIALOG SHOW MODAL  hSpin, CALL DlgSpProc()



END FUNCTION







   CALLBACK FUNCTION DlgSpProc() AS LONG


    SELECT CASE CB.MSG
        CASE %WM_INITDIALOG
            ' setup the timers
              hAtim = settimer(CB.HNDL, %IDC_ATimer, 15, 0)
              hBtim = settimer(CB.HNDL, %IDC_BTimer, 150, 0)
              hCtim = settimer(CB.HNDL, %IDC_CTimer, 200, 0)



      CASE %WM_TIMER
            IF hAtim THEN
                ' Do stuff A  --- this is a ONE time process  -- after this we kill the associated timer
                killtimer(CB.HNDL, %IDC_ATimer)
                hATim = 0​
            END IF

            IF hBtim THEN
                ' Do stuff B
            END IF
            IF hCtim THEN
                ' Do stuff C
            END IF




      CASE %WM_DESTROY
            ' clean up the timers
             IF hATim THEN
                killtimer(CB.HNDL, %IDC_ATimer)
                hATim = 0
             END IF
             IF hBTim THEN
                killtimer(CB.HNDL, %IDC_BTimer)
                hBTim = 0
             END IF
             IF hCTim THEN
                killtimer(CB.HNDL, %IDC_CTimer)
                hCTim = 0
             END IF



  END SELECT


 END FUNCTION




​

[Tim Lakinir]

That is like having a message block under CASE %WM_TIMER to run 3 different processes and all processes are to be done at different times intervals

[Michael Mattias]

Checking the ID you assigned to the timer under the WM_TIMER message is correct.

However, are you sure you need/want to use timers to accomplish whatever it is you wish to accomplish.

Is this it?

That is like having a message block under CASE %WM_TIMER to run 3 different processes and all processes are to be done at different times intervals

That is, is your application some kind if "supervisory" program?

If not, please describe that proposed application .

[Tim Lakinir]

Thanks Michael, yes it kinda of supervisory to ensure a graphics control is progressively updated , check the status of a spinner cursor and check whether a another external program's
computation has completed etc, looking at my skeleton code will it encounter problems later on?

[Jules Marchildon]

Tim-san, Just a suggestion, instead of the IF statements, use your ID's in a select case block like below.

CASE %WM_TIMER
    SELECT CASE CB.CTL
        CASE %ID_TIMER1
            '-ACTION JACKSON
        CASE %ID_TIMER2
            '-IS MY NAME!
        CASE %ID_TIMER3
            '-BOLD ADVENTURE
        CASE %ID_TIMER4
            '-IS MY GAME!
     END SELECT

@looking at my skeleton code will it encounter problems later on?
Keep in the back of your mind, the WM_TIMER message is a low priority messages.

[Michael Mattias]

looking at my skeleton code will it encounter problems later on?

Other than performance, no; looping to constantly check if something has happened is always less efficient than waiting for the something to happen.

However, maybe you could have the external program set an event, and your program could wait on it in another thread and when the wait is satisfied you could post a private message to your dialog. That way you never do a 'check for ...' which comes up "No" AND your dialog could continue to do something useful without a needless interruption. That's what I would have done. (Actually, it's what I have done.)

But I can guarantee using a timer and looping is easier to code and test.

You get what you pay for.

[Dale Yarker]

  CASE %WM_TIMER
    IF hAtim THEN​

Does not work because hAtim will always be true no matter which timer caused the %WM_TIMER message.

  CASE %WM_TIMER
    SELECT CASE CB.CTL
        CASE %ID_TIMER1​

should be

  CASE %WM_TIMER
    SELECT CASE CB.WPARAM
        CASE %ID_TIMER1​

because the message is not %WM_COMMAND. CB.CTL happens to work for %WM_TIMER but is a bad habit to develope.
See - CB Callback functions in Help.

Cheers,

[Stuart McLachlan]

' Multiple Timers.bas
...
CALLBACK FUNCTION DlgSpProc() AS LONG
...
hAtim = settimer(CB.HNDL, %IDC_ATimer, 15, 0)
hBtim = settimer(CB.HNDL, %IDC_BTimer, 150, 0)
hCtim = settimer(CB.HNDL, %IDC_CTimer, 200, 0)
...
CASE %WM_TIMER
IF hAtim THEN
' Do stuff A --- this is a ONE time process -- after this we kill the associated timer
killtimer(CB.HNDL, %IDC_ATimer)
hATim = 0
END IF

IF hBtim THEN
' Do stuff B
END IF
IF hCtim THEN
' Do stuff C
END IF
[/CODE]

Another example of poor grasp of fundamental logic as opposed to lack of programming skills.

You will "Do stuff A" ,"Do stuff B" and "Do stuff "C" after 15 ms.

From then on, you will "Do stuff B" and "Do stuff C"
at 150,200,300,400,450,600 (twice),750, 800, 950 and 1000 milliseconds.

See if you can work out why!

[Michael Mattias]

You will "Do stuff A" ,"Do stuff B" and "Do stuff "C" after 15 ms.

Not if he checks the Timer ID on WM_TIMER.

Of course, the pseudo-code in post #1 is not getting the Atim Btim and CTim correctly ; it's wParam ("CB.WPARAM").

[Stuart McLachlan]

Not if he checks the Timer ID on WM_TIMER.

That was the whole point of my post which included his incorrect code. He doesn't!

Of course, the pseudo-code in post #1

What "pseudo-code" ? He posted actual PowerBASIC code, not "pseudocode".

s not getting the Atim Btim and CTim correctly

He IS "getting" them correctly, although he is not checking that they are valid
hAtim = settimer(CB.HNDL, %IDC_ATimer, 15, 0)will return %IDC_ATimer in hAtim (or 0 if it fails)
Of course there is real need to get them since he can just use %IDC_ATimer etc directly.

it's wParam ("CB.WPARAM").

He should be "checking" CB.WPARAM and comparing it to hAtim or %IDC_ATimer etc, but that's a different issue.

[Michael Mattias]

What "pseudo-code" ? He posted actual PowerBASIC code, not "pseudocode".

???? 'Do Stuff A' and 'Do Stuff B' (even though commented out) are hardly actual (syntactically correct) PB Code. And commented out as shown creates and IF .. END IF block missing "imperative statement" which is allowed in the block construction but not in the single-line format. Regardless an IF.. END IF with nothing do is, if not illegal, silly; so let's call it pseudocode to avoid embarrasing Mr. Lakinir.

You may well be borderline 'pedantic-retentive.'

[Dale Yarker]

In post 1 is not pseudocode..

[Stuart McLachlan]

???? 'Do Stuff A' and 'Do Stuff B' (even though commented out) are hardly actual (syntactically correct) PB Code. And commented out as shown creates and IF .. END IF block missing "imperative statement" which is allowed in the block construction but not in the single-line format. Regardless an IF.. END IF with nothing do is, if not illegal, silly; so let's call it pseudocode to avoid embarrasing Mr. Lakinir.

No lets call it "unfinished application code". To avoid embarrassing ourselves.

The posted code compiles with no error in PBWin, so it is obviously not "pseudocode" by any standard definition.

Pseduocode dees NOT use commented out lines to identify actions. Commented lines are a clear indication of actual code that is intended to be compiled..

Conditionals such as If...END with no current callable instructions and containing comments indicating as yet undeveloped functions or or-line code are commonly used by any competent developer.

Since you are apparently unaware of this practice, let me explain:
Such constrcuts are used as "placeholders" so that other parts of the application can be compiled and tested. To do otherwise means that you can't do progressive/ unit testing during your development cycle,

Do you really not use this paradigm when developing?

[Michael Mattias]

Do you really not use this paradigm when developing?

Yes I do (or maybe I should say "When I did" )... and always called it pseudocode!

[Stuart McLachlan]

Yes I do (or maybe I should say "When I did" )... and always called it pseudocode!

The correct term for that would be "skeleton code" or "dummy code". Pseudocode is something very different.

https://en.wikipedia.org/wiki/Pseudocode.

https://en.wikipedia.org/wiki/Skelet...er_programming)