What _getvideoconfig() Returns for Non-Standard Adapters

MS-DOS                      | WINDOWS

The information in this article applies to:

• The C Run-time (CRT), included with:

      - Microsoft C for MS-DOS, versions 5.1, 6.0, 6.0a, and 6.0ax
      - Microsoft C/C++ for MS-DOS, version 7.0
      - Microsoft Visual C++ for Windows, versions 1.00 and 1.50
  

The _getvideoconfig() run-time library function returns, among other things, the type of the current display adapter. The possible return values are documented. Problems can occur when the adapter does not match any of the cards represented by the nine manifest constants defined in graph.h.

When the adapter is recognized as a "superset" of an adapter that is supported, the value of the supported adapter is returned. For example, if the adapter is a Super VGA card, the value _VGA is returned.

When the active adapter is completely unrecognized, the _getvideoconfig() function returns the least common denominator. If the adapter supports color, _CGA is returned; otherwise the return value is set to _MDPA.

A good programming strategy to reduce device dependencies is to use _MAXRESMODE or _MAXCOLORMODE when calling _setvideomode(), and using _getvideoconfig() to determine what mode was actually set. There is more information on these topics in the Microsoft Advisor online Help system that is included with your C compiler package.