## Virtual Device Driver Reference for OS/2

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### VDHMapPages Parameter - pvdhmtTargetRegion

pvdhmtTargetRegion (PVDHMAPTARGET) Target region definition. Pointer to VDHMAPTARGET structure.

VDHMAPTARGET is the target region definition for VDHMapPages with a data structure as follows:

    typedef struct VDHMapTarget_s {

        ULONG   vdhmt_laddr;     /* Address in V86-space to be      */

                                 /* mapped.                         */

                                 /* (0 <= vdhmt_laddr < 1MB+64KB)   */

        ULONG   vdhmt_cpg;       /* Count of pages to map.          */

        ULONG   vdhmt_hmap;      /* Mapping handle. Must be zero on */

                                 /* the first call to VDHMapPages   */

                                 /* for region.  Set by the service */

                                 /* to hold a handle used for       */

                                 /* remapping the region. The handle*/

                                 /* is reset each time it is used.  */

                                 /* vdhmt_hmap must be the value    */

                                 /* returned from the previous      */

                                 /* VDHMapPages call for the region */

                                 /* unless the pages are either     */

                                 /* already invalid or else are     */

                                 /* being made invalid.  If either  */

                                 /* the old or new mapping is       */

                                 /* invalid pages, vdhmt_hmap can   */

                                 /* be 0.                           */

                                 /* Making a region invalid restores*/

                                 /* pages in the region to their    */

                                 /* reserved state, and sets        */

                                 /* vdhmt_hmap to 0.                */

    } VDHMAPTARGET;

    typedef VDHMAPTARGET *PVDHMAPTARGET;