Q59005: Returning to QuickC from PM May Corrupt Screen

Article: Q59005
Product(s): See article
Version(s): m2.00 2.01
Operating System(s): OS/2
Keyword(s): ENDUSER | buglist2.00 buglist2.01 | mspl13_c
Last Modified: 6-MAR-1990

If you are doing graphics in QuickC, returning to the DOS box from
Presentation Manager (PM) and then exiting Quick C may generate red
and white stripes on a flashing background in the DOS compatibility
box. Mouse support will be disabled for the DOS compatibility box.
This problem occurs when you exit from QuickC without returning the
video mode to _DEFAULTMODE. Restoring the video mode to default
prevents the problem.

The effect can be demonstrated by doing the following:

1. Execute the program (shown below) at the command line,

       QCL BOX.C GRAPHICS.LIB

2. Run the resulting .EXE either from the command line or in the
   environment.

3. Enter QuickC, as follows:

       QC  (no file required to demonstrate the problem)

4. Press CTRL+ESC to Presentation Manager.

5. Re-enter the DOS compatibility box.

6. Exit Quick C, as follows:

      ALT+F.Exit

Sample Code
-----------

#include <graph.h>
void main()
{
   _setvideomode(_VRES16COLOR);
/* _setvideomode(_DEFAULTMODE);  uncomment to correct behavior */
}

Microsoft has confirmed this to be a problem with QuickC Versions 2.00
and 2.01. We are researching this problem and will post new
information here as it becomes available.

This problem has been reproduced on a WYSE 386 with a FastWrite VGA
and on a WYSE 286 with a Genoa Super VGA board. It has not been
reproduced on a Compaq.

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