Queries the code page currently used to display text data.

#define INCL_VIO
#include <os2.h>

ULONG      Reserved;    /*  Reserved.  Must be 0. */
PUSHORT    CodePageID;  /*  Code-page ID. */
HVIO       VioHandle;   /*  Presentation-space handle. */
APIRET     rc;          /*  Return code. */

rc = VioGetCp(Reserved, CodePageID, VioHandle);