This example queries the disable-foreground attribute; if it is a valid attribute of the window, it is removed via WinRemovePresParam.

#define INCL_WINSYS
#include <OS2.H>

HWND  hwnd;
ULONG AttrFound;
ULONG AttrValue[32];
ULONG cbRetLen;

cbRetLen = WinQueryPresParam(hwnd,
                             PP_DISABLEDFOREGROUNDCOLORINDEX,
                             0,
                             &AttrFound,
                             sizeof(AttrValue),
                             &AttrValue,
                             QPF_ID1COLORINDEX | QPF_NOINHERIT);

if(PP_DISABLEDFOREGROUNDCOLORINDEX == AttrFound)

WinRemovePresParam(hwnd,
                   PP_DISABLEDFOREGROUNDCOLORINDEX);