INF: What _getvideoconfig() Returns for Non-Standard Adapters

ID Number: Q66287

5.00 5.10 6.00 6.00a 6.00ax 7.00

MS-DOS

Summary:

In Microsoft C versions 5.0, 5.1, 6.0, 6.0a, 6.0ax, and C/C++ version

7.0, the _getvideoconfig() run-time library function returns, among

other things, the type of the current display adapter. The possible

return values are documented. However, what if 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.

Additional reference words: 5.00 5.10 6.00 6.00a 6.00ax 7.00