Messagebox in separate thread

[Arie Verheul]

Mike, thank you for the example, but i think this is not the equivalent of the WinApi Messagebox.
The concerns that were brought forward were not about forwarding a string to the screen,
but rather about properly reading the return value by the main program when one of the buttons is clicked.

Michael, thanks for your reply.
It is clear to me that any operation that involves more than one instruction may be interrupted
by thread switching. From Pauls reply i learned that the operation A=B involves also two instructions.

Edwin, thanks. I will try that.

Paul, thanks. Your reply is very clear: the alignment issue is not present in PB.
But on the downside, the operation A = B does not involve one instruction, as i supposed, but two,
and may therefore be interrupted by thread switching.

Therefore it may be concluded that a 32 bit variable is not guaranteed put in place in one single
operation, as i supposed. This implies that synchronisation techniques are required at all times.

Arie Verheul

[Mike Doty]

Mike, thank you for the example, but i think this is not the equivalent of the WinApi Messagebox.

Just change the line with ? to whatever you want.

[Mike Doty]

Win32 Message box in the background

DECLARE FUNCTION MessageBox LIB "USER32.DLL" ALIAS "MessageBoxA" _
               (BYVAL hWnd           AS DWORD,     _
                    lpText           AS ASCIIZ,    _
                    lpCaption        AS ASCIIZ, _
                    BYVAL dwType     AS DWORD) AS LONG
TYPE MyUDT
  hWnd       AS DWORD
  lpText     AS ASCIIZ * 128
  lpCaption  AS ASCIIZ * 128
  dwType     AS DWORD
END TYPE
FUNCTION PBMAIN&
  mb 0,"How now brown cow","Title", %MB_ICONERROR
  ? "Click to exit"
END FUNCTION
SUB MB(hWnd AS DWORD, lpText AS ASCIIZ,lpCaption AS ASCIIZ,dwType AS DWORD)
  LOCAL x AS MyUDT, hThread AS DWORD
  x.hWnd       = hWnd
  x.lpText     = lpText
  x.lpCaption  = lpCaption
  x.dwType     = dwType
  THREAD CREATE MessageBoxThread(VARPTR(x)) TO hThread???
  SLEEP 50
  THREAD CLOSE hThread??? TO hThread???
END SUB
THREAD FUNCTION MessageBoxThread(BYVAL y AS DWORD) AS DWORD
  LOCAL x  AS MyUDT POINTER
  LOCAL hWnd       AS DWORD
  LOCAL lpText     AS ASCIIZ * 128
  LOCAL lpCaption  AS ASCIIZ * 128
  LOCAL dwType     AS DWORD
  x = y
  MessageBox @x.hWnd,@x.lpText,@x.lpCaption,@x.dwType
END FUNCTION

[Michael Mattias]

This implies that synchronisation techniques are required at all times [in multi-thread programs]

You know, it really does 'make my day' when one or more persons 'see the light' on one of these otherwise esoteric things about which I often post.

Thank you for letting me know.

MCM