topic Console painting over Quickwin window in Software Archive

Console painting over Quickwin window

mroczek — Tue, 09 Jan 2001 13:15:07 GMT

For convenience and safety I launch an old Fortran ?legacy? console program from my Quickwin application using the techniques previously discussed in this forum and in the samples (using createprocess etc). It all works very well except that if the user moves the console window about the desktop the Quickwin windows are painted over by the console window so that there appear to be numerous copies of the console window pasted all over the Quickwin windows. Once the console app terminates the Quickwin application releases the console handle for the process, the console window copies all disappear. However I can?t close the process handle prematurely (i.e as soon as the process is launched) as it needs to passed to ?waitforsingleobject? and ?getexitcodeprocess? routines. Any ideas of how to get around this?

Thanks for any assistance

Ed

Re: Console painting over Quickwin window

Jugoslav_Dujic — Tue, 09 Jan 2001 23:47:17 GMT

Well, you can't have'em both...
When you start the .exe using that mechanism, the calling
application gets blocked, which includes also updating its
window. These things tend to happen when an application
invokes a long-lasting process from its main thread... this
happens for example, to Word during a long AutoSave or
VisualStudio upon saving a large Workspace.

The "right" way to launch a long-lasting process is to create
it in a separate thread and to ensure that nothing harmful
may happen in the calling process (i.e. disable menus, mouse
actions which may affect the program state etc.), while keeping
the calling process unblocked.

Luckily, the QuickWin already has two threads: in the
"secondary", PROGRAM (and subroutines called from it) are
executed; in the "primary", mouse and menu clicks are
handled, along with window updating (and lot of other things
hidden beneath the surface). If you put CreateProcess...
in a, say, menu callback, you block the "primary" thread.
Instead, define a global flag called, say, "bExecProcess"
and put something like the following in the endless loop
at the PROGRAM end:

 
DO WHILE (.TRUE.) 
    IF (bExecProcess) THEN 
        !TODO Disable menus and whatever else necessary here 
        hProcess = CreateProcess... 
        iSt = WaitForSingleObject... 
        bExecProcess = .FALSE. 
    END IF 
END DO

and, in the menu callback subroutine, just set
the value of bExecProcess to .TRUE.

HTH

Jugoslav

Re: Console painting over Quickwin window

mroczek — Wed, 10 Jan 2001 07:53:36 GMT

Jugoslav, Yes that was the problem. I was calling Createprocess from a menu callback function. Now I only set up some parameters in the callback and call createprocess in the main program.

Your help was much appreciated.

Ed