## Presentation Device Driver Reference for OS/2

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### GreGetScreenChangeArea - Syntax

Simulation support:

This function is mandatory for display drivers that want to be DCAF-enabled .

Description GreGetScreenChangeArea takes an SCA handle and, for the identified SCA, adds its rectangles to the region pointed to by the phrgn field. The SCA is reset to NULL as a result of this call.

    #define INCL_GRE_SCREEN

    #include <os2.h>

    #include <pmddi.h>

    HDC      hdc;     /*  Any valid device context. */

    HSCA     hsca;    /*  Handle of the SCA to be queried. */

    PHRGN    phrgn;   /*  Pointer to a region handle. */

    PDC      pdcArg;  /*  Pointer to instance data. */

    ULONG    FunN;    /*  High-order word=Flags; Low-order word=NGreGetScreenArea. */

    LONG     rc;

    rc = GreGetScreenChangeArea(hdc, hsca, phrgn,

           pdcArg, FunN);