Q34623: _remappalette(8,_GRAY) Does Not Work Correctly

Article: Q34623
Product(s): See article
Version(s): 5.10   | 5.10
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | bug | mspl13_c
Last Modified: 12-OCT-1988

_remappalette(pixel,color) maps the number "pixel" to the value
"color" and is suppose to return the previous color value. However,
when this function is invoked as _remappalette(8,_GRAY), the value
associated with _WHITE is returned.

Microsoft is researching this problem and will post new information as
it becomes available.

To demonstrate this problem, do the following:

1. cl the following source-code chunklet with /Od /Zi
   switches.

2. Go into CodeView.

3. Set N16 to look at the value err returned by _remappalette() in hex,
   then compare the value with values for the colors in graph.h. You
   may want to make a hardcopy of these values prior to cving. The
   correct value is returned on the zeroth pass, but then erroneous
   values are returned. This has been raided.

4. Use cv /S, where the S is for switching screen modes.

The following sample code demonstrates the problem:

         #include <stdio.h>
         #include <graph,h>
         main()
         {
            int i;
            long err;
            _setvideomode(_HRES16COLOR);
            for (i=0;i<16;i++)
            {
              err=_remappalette(8,_GRAY);
              printf("%x\n",err);
            }
            _setvideomode(_DEFAULTMODE);
         }

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