Stange Thing On Graphic Copy

[kunhock Koo]

I have a small program that read from clipboard buffer to a graphic window, code as below.

LOCAL GraphicWindow AS DWORD
LOCAL GraphicHandle AS DWORD , x AS LONG

CLIPBOARD GET BITMAP GraphicHandle, x
GRAPHIC WINDOW "Graphic window", 0, 0 , 800, 600 TO GraphicWindow
GRAPHIC ATTACH GraphicWindow, 0
GRAPHIC COPY GraphicHandle, 0
SLEEP 5000

The program work fine in debug mode, but the graphic window shows nothing when it is run in compiled mode.

Help is deeply appreciated !

Regards.

Kunhock

[Gösta H. Lovgren-2]

Deleted as Dave (below) found the answer.

=================================
"He who has a 'why' to live,
can bear with almost any 'how'."
Friedrich Nietzsche (1844-1900)
=================================

[Dave Biggs]

There does seem to be something odd going on here.
Try this test code (with something on the clipboard eg from Alt-Print Scrn)..

#Dim All 
#INCLUDE "WIN32API.INC"
 
FUNCTION PBMAIN()
 LOCAL X AS LONG                      ' Note different arrangements below
 LOCAL GraphicWindow AS DWORD
 LOCAL GraphicHandle AS DWORD
 
  CLIPBOARD GET BITMAP GraphicHandle, x
  GRAPHIC WINDOW "Graphic window", 0, 0 , 800, 600 TO GraphicWindow
  GRAPHIC ATTACH GraphicWindow, 0
  GRAPHIC COPY GraphicHandle, 0
 
  GRAPHIC ATTACH GraphicHandle, 0
  GRAPHIC BITMAP END
 
  SLEEP 5000
 
END FUNCTION
'------------------/PBMain
#IF 0
 LOCAL X AS LONG                      ' OK
 LOCAL GraphicWindow AS DWORD
 LOCAL GraphicHandle AS DWORD
 
 
 LOCAL GraphicWindow AS DWORD         ' Not OK
 LOCAL GraphicHandle AS DWORD
 LOCAL X AS LONG
 
 
 LOCAL GraphicWindow AS DWORD         ' OK   !
 STATIC GraphicHandle AS DWORD
 LOCAL X AS LONG
#ENDIF

I get different results just by repositioning the declaration of the 'X' variable. Using STATIC for the Bitmap handle also has some effect !!??
All variants work when run in debug mode.

[kunhock Koo]

Thanks ..

Thanks ..you saved my life ..

I like the static declaration. But .. still wonder why the pointer run away ..

Regards.

Kunhock

[Scott Slater]

Did you try adding #Register None before the declares? Can they be defined in any order with this added?

[Dave Biggs]

Good catch Scott. Indeed it does seem that the problem occurs when GraphicHandle is assigned as a register variable (unless told otherwise PB automatically classifies the first two integer variables as Register variables).

The 'cure' is to ensure that..
1. #Register None is applied. or
2. There are at least two other integer variables assigned ahead of GraphicHandle (at present only two integer variables are automatically classified as register variables - "may change in the future"). or
3. Declare GraphicHandle as a Static (or Global) variable.