This function queries available code pages.

#define INCL_WINCOUNTRY /* Or use INCL_WIN, INCL_PM, */
#include <os2.h>

HAB       hab;          /*  Anchor-block handle. */
ULONG     ulcount;      /*  Maximum number of code pages returned. */
PULONG    aulCodepage;  /*  Code page list. */
ULONG     ulTotCount;   /*  Total number of code pages available. */

ulTotCount = WinQueryCpList(hab, ulcount,
               aulCodepage);