Q62270: Problem with SCREEN 0 Paging on CGA in QB.EXE & QBX.EXE

Article: Q62270
Product(s): See article
Version(s): 7.00 7.10
Operating System(s): MS-DOS
Keyword(s): ENDUSER | SR# S900517-177 B_QuickBas buglist7.00 buglist7.10 | mspl13_basic
Last Modified: 6-AUG-1990

Paging through the active and visible pages of SCREEN 0 does not work
correctly on a CGA monitor in the QBX.EXE or QB.EXE environment  This
problem occurs only when single-stepping through a program and setting
breakpoints to view the output of the various pages. Machines equipped
with EGA or VGA video adapters do not demonstrate this problem.

Microsoft has confirmed this to be a problem in the QB.EXE environment
QuickBASIC version 4.50 (buglist4.50) and in the QBX.EXE environment
of Microsoft BASIC Professional Development System (PDS) versions 7.00
and 7.10. We are researching this problem and will post new
information here as it becomes available.

This problem does not occur in QuickBASIC versions 4.00 and 4.00b.

The following code example demonstrates the problem in QB.EXE or
QBX.EXE. Step through the program using the F8 key. After the PRINT
statement, press the F4 function key to view the output screen. The
screen will not be updated on a CGA monitor.

Code Example
------------

   DEFINT A-Z
   DO UNTIL INKEY$ <> ""
      SCREEN 0, 0, x, x
      CLS
      PRINT "SCREEN MODE 0, PAGE"; x
      x = x + 1          ' Press F4 key to view the output screen
      IF x = 8 THEN x = 0
   LOOP

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