## Presentation Device Driver Reference for OS/2

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### GreQueryClipRegion - Syntax

Simulation support:

This function is simulated by a handling routine in the graphics engine.

Description

GreQueryClipRegion returns the handle of the currently selected clip region , or NULL (if none exists).

This function can be hooked by the presentation driver.

    #define INCL_GRE_CLIP

    #include <os2.h>

    HDC      hdc;        /*  Device context handle. */

    PVOID    pInstance;  /*  Pointer to instance data. */

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

    HRGN     rc;         /*  This function returns the handle of the clip region: */

    rc = GreQueryClipRegion(hdc, pInstance, lFunction);