Q33685: "Illegal Function Call" Using SCREEN 0 Pages, then SCREEN 1

Article: Q33685
Product(s): See article
Version(s): 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | B_BasicCom buglist4.00 buglist4.00b fixlist4.50 | mspl13_basic
Last Modified: 5-DEC-1988

When invoking multiple video pages (as in SCREEN 0) and then switching
to a SCREEN that does not support multiple pages (SCREEN 1), the error
"Illegal function call" will occur on the second SCREEN statement, as
in the following example:

   SCREEN 0,,1,0
   SCREEN 1       'This gives "Illegal function call"

Microsoft has confirmed this to be a problem in QuickBASIC Versions
4.00 and 4.00b, and in the Microsoft BASIC Compiler Version 6.00 for
MS-DOS and MS OS/2 (buglist6.00). This problem was corrected in
QuickBASIC Version 4.50.

A workaround is to reset both pages to zero with another SCREEN
statement just before changing screen modes, as in the following code
example:

SCREEN 0,,1,0
SCREEN 0,,0,0  'Resets both pages to 0
SCREEN 1

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