## Presentation Device Driver Reference for OS/2

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### GreDeviceInvalidateVisRegion - Syntax

Simulation support:

This function is mandatory for display drivers. For other drivers, it is simulated by a handling routine in the graphics engine.

Description:

GreDeviceInvalidateVisRegion notifies the presentation driver that the visible region and DC region of one or more DCs has changed, and that the affected DCs must revalidate their visible regions before drawing in them.

    #define INCL_GRE_DEVMISC2

    #include <os2.h>

    HDC          hdc;        /*  The device context handle. */

    LONG         cArray;     /*  The number of elements in the array. */

    PDC_BLOCK    paBlock;

    PVOID        pInstance;  /*  A pointer to instance data. */

    ULONG        lFunction;  /*  High-order WORD=flags; low-order WORD=NGreDeath. */

    BOOL         fSuccess;   /*  Return codes. */

    fSuccess = GreDeviceInvalidateVisRegion(hdc,

                 cArray, paBlock, pInstance, lFunction);