WaitForSingleObject - pass what handle in WinMain?

[Mike Doty]

'Can't get WaitForSingleObject to work.
'What handle is passed in main thread?

'handle.bas
#DIM ALL
#COMPILE EXE
DECLARE FUNCTION wait(hThread AS DWORD) AS STRING
#INCLUDE "win32api.inc"
FUNCTION WINMAIN( _
            BYVAL  hInstance    AS DWORD, _
            BYVAL  hPrevInst    AS DWORD, _
            BYVAL  lpszCmdLine  AS ASCIIZ PTR, _
            BYVAL  nCmdShow     AS LONG ) AS LONG
 
  LOCAL zBuffer AS ASCIIZ * %MAX_PATH
  LOCAL s AS STRING
  LOCAL dw AS DWORD
  LOCAL h AS LONG
  LOCAL result AS LONG
 
  h = %HWND_DESKTOP
  dw = WaitForSingleObject(h, %INFINITE)
  result = GetLastError()
  FormatMessage %FORMAT_MESSAGE_FROM_SYSTEM, BYVAL %NULL, Result, %NULL, zBuffer, SIZEOF(zBuffer), BYVAL %NULL
  MSGBOX zBuffer
 
 
  'This works
  MSGBOX "Test MSGBOX"
  Result = GetLastError()
  FormatMessage %FORMAT_MESSAGE_FROM_SYSTEM, BYVAL %NULL, Result, %NULL, zBuffer, SIZEOF(zBuffer), BYVAL %NULL
  MSGBOX zBuffer
  FUNCTION = 1
 
END FUNCTION

[Peter Lameijn]

It's not very clear to me what you want WaitForSingleObject to do exactly... Wait on Windows desktop shutdown?

[Mike Doty]

Correct. It should not return 6.
What handle is passed to WaitForSingleObject?

[Peter Lameijn]

hDeskTop = GetDesktopWindow()

[Michael Mattias]

>Correct. It should not return 6.

%ERROR_INVALID_HANDLE            = 6

Yes, it should return "6" because you can't WFSO on a window handle, making "h" an "invalid handle" for this function.

If you want your program to "do something" on shutdown or logoff, you should intercept the WM_QUERYENDSESSION and/or WM_ENDSESSION notification messages and react to one and/or the other.

[Michael Mattias]

FWIW:

The WaitForSingleObject function can wait for the following objects:

• Change notification
• Console input
• Event
• Job
• Memory resource notification
• Mutex
• Process
• Semaphore
• Thread
• Waitable timer

Also FWIW, in PB/CC you can intercept a shutdown or logoff by using SetConsoleCtrlHandler and 'doing something' on either CTRL_SHUTDOWN_EVENT or CTRL_LOGOFF_EVENT

[Mike Doty]

This code works in batch files so output can be paused before exiting.
Why does command prompt come back instantly with SLEEP 4000?

#COMPILE EXE  "c:\misc\sleep.exe"   'in path
FUNCTION PBMAIN AS LONG
  SLEEP VAL(COMMAND$)
END FUNCTION

Never mind, Start/Wait 4000 works.